Document 93KXL8xL9y0JnzkVywrBRB2VD

Jan u a ry 2 0 , 1976 UNITED STATES DEPARTMENT OF COMMERCE National Bureau of Standards Washington. O.C. E0234 211.06 Phone: (301) 921-3121 D r. R obert C. O sthoff G en eral E l e c t r i c Company 100 Woodlawn Avenue P i t t s f i e l d , MA 01201 Dear Dr. O sthoff: Enclosed Is a d ra ft copy of the "cu rren t sta tu s" p o rtio n of our In su la tin g F luids R eport. Tour co n trib u tio n s were very h e lp fu l In pur p rep aratio n of t h i s s e c tio n and now we would a p p r e c ia te your f u r th e r h e lp in p ro v id in g a rev iew o f t h i s d r a f t to I d e n tif y any e r r o r s o f I n t e r p r e t a t i o n w hich may have crept In. S ince most o f th e p r o je c t team members a r e lo c a te d h e re , D r. M ille r h as s u g g e ste d you a d d re ss your comments to me. Comments re c e iv e d by F eb ru ary 2 w ill be a v a ila b le fo r c o n sid e ra tio n a t th e nex t d a y 's m eeting of th e team, b u t comments which a r r iv e l a t e r w i l l be e q u a lly welcome. S in c e re ly , F . RALPH KOTTER, P h y s ic is t High V oltage Measurements S ectio n E l e c t r i c i t y D iv is io n , IBS Enclosure GENP 006064 774713 yjMJTIQ* Draft Section 2 Status Table o f Contents 2.1 Introduction -- Askarel transform ers and c ap a c ito rs 2 .1 .1 Transformers 2 .1 .2 C apacitors 2.1 .3 References Page 1 1 2 ** 2.2 "A skarel-class" transform ers 2 .2 .1 2 .2 .2 2 .2 .3 2 .2 .k 2 .2 .5 2 .2 .6 D escription of the "ask arel-ciass" of transform ers Sources and consequences o f transform er tank rupture F u ll-u n it arc te stin g A lternatives to askarels in "ask arel-class" transform ers T est techniques and standards used by m anufacturers to ev alu ate flu id -fille d transform ers References 2 .3 "A s k a re l-c la s s " c a p a c ito rs 2.3.1 D escription-of the "ask arel-class" of capacitors 2 .3 .2 . P ro b a b ility and consequences o f ru p tu re 2 .3 - 3 Full capacitor arc te stin g 2 .3 - k E ffect of a lte rn a tiv e flu id s on design and te s tin g of the f u ll capacitor unit 2 .3 .5 Test techniques and standards used by m anufacturers and u sers to evaluate flu id -fille d cap acito rs and cables 2.3.6 References 5 5 3 13 15 18 23 2k 2k 25 .26 27 30 3^ 2.1* D ie le c tr ic and in s u la tin g f l u i d s 2.U .1 2.U .2 2.1*.3 2.U.U 2.1*.5 2.1*. 6 A vailable flu id s Test techniques and stan d ard s by which flu id m a te ria l p ro p e rtie s are evaluated Test techniques by which flu id flam m ability is ev alu ated Test techniques by which to x ic ity is evaluated Test techniques by which d e g ra d a b ility is evaluated References 2 .5 The scope and in flu e n c e o f government r e g u la tio n s 2 .5 .1 2 .5 .2 2.5*3 2.5.1 Environmental reg u latio n s Poisonous in g red ien ts in foods Occupational health T ra n sp o rta tio n 2 .6 The scope and in flu e n c e o f in s u ra n c e and f ir e - c o d e re q u ire m e n ts o 35 35 51 53 62 62 62 66 66 6 6i Ti V 2! 774714 o o ON o ON L/l 2.1 Introduction - Askarel transformers and capacitors 2.1.1 Transformers Electrical transformers are used to change voltage, current and impedance levels in a wide variety of applications in electrical apparatus. These trans formers range from the very smallest types in solid-state electronic circuitry to very large (1000MVA) 60-Hz power transformers. This study is concerned with the following restricted but important set of transformers: 1. "Network"-type distribution transformers, 500-2500 kVA, 12-3^ kV, used in heavily concentrated urban and industrial load areas. 2. Precipitation transformers, high-voltage, for electrostatic precipi tators which remove particulate pollutants from furnace exhaust gases. 3. Transformers for multiple-unit type electric railroad cars; these are located under the flat-bed of the car. These are all 1iquid-insulated and operate at the commercial power frequency. The liquid insulant has two duties, electrical insulation and cooling. Com pared with air insulation, the liquid allows much closer spacing (smaller size) for a given voltage, and compared with air or solid insulation ("dry-type"), the circulating liquid coolant leads to a much smaller size for a given power rating. Mineral oil was traditionally used for this purpose and is still used for most power transformer applications. Estimates are that as much as 98* of all liquidcooled power transformers use mineral oil, on an MVA or gaIlon-of-coolant basis. The particular set of applications described above have critical non flammability requirements, however, since the/ are generally located In heavily populated areas or are used in high-temperature or high fire-risk conditions. "Askarel" transformer liquid was developed, using blends of the polychlorinated biphenyls (PCB's), In the early 1930's to replace mineral oil in applications where non-flammability was an important requirement. The PCB's for these CifcNP 006066 774715 1 transformer askarels are manufactured by Monsanto Industrial Chemicals Company and are blended by Monsanto under the trade name "Aroclor." Two grades are used (showing percent chlorination and 197^ domestic sales in thousands of pounds.) Aroclor 12^2 (1*2%) 6207 Aroclor 125^ (5W 6185 Ten to twenty percent of this production goes into precipitator and railroad transformers; most of the remainder is used in the "network" transformers. Approximately 5000 askarel-fi11ed transformers are manufactured per year in the U. S., at a value of about $^5 million. While essentially all precipitator and railroad transformers are askarelfilled, only 10-153 of network transformers are the askarel-type. 2.1.2 Capac itors As in the case of transformers, there is also a wide range in types and sizes of capacitors which are used in electrical apparatus. These are used for electric energy storage, tuning and power factor correction purposes. Their ratings can go from a few picofarads to many microfarads, with voltages from a few volts to over one-hundred kilovolts. Although some high-frequency capacitors use air dielectric (air insulation), most capacitors are made up of multiple, thin layers of metal and solid insulation. To eliminate any weakening by the presence of air, these layer assemblies are then totally immersed in a liquid dielectric; often paper Is used as one part of the solid insulator, and this paper is Impregnated by the liquid. In addition to being a good electrical Insulator, the liquid should have a high permittivity (dielectric constant,c). The PCB's possess both of these features, and so grad* of capacitor askarels have been used in capacitors since the introduction of tf* askarels in the 1930's. Whereas only a small percentage of transformers conta 774 7 16 askarel, nearly one-hundred percent of capacitors use this type of liquid insulant. Because of the widespread use of PCB's in capacitors, Monsanto Tn 1971 introduced a more environmentally compatible formulation, Aroclor 1016, especially for capacitors. In 1974, Monsanto sold 21,955 thousand pounds of this fluid; the .capacitor market for PCB's is considerably greater than the transformer PCB demand. The market value for PCB-insulated capacitors is.in excess of $100 mi 11 ion per year. Askarel capacitors are often divided into two categories, "power" and "industrial." The power capacitors are high voltage units which generally contain several gallons of fluid. They are used for power factor correction, which in creases the efficiency of the electric power system. Without this efficiency improvement, approximately $1 billion in extra electric power plant and about 40M KWH in extra electric energy per year would be required to serve existing demand. "Industrial" capacitors are generally smaller units which serve a large number of purposes including motor start and run, fluorescent light ballasts, arc welders, and power supply filters. The industrial class of capacitors is estimated to use one-half to two-thirds of the demand for capacitor askarel. There is an important economic interdependence between the capacitor and trans former fluids markets which should not be overlooked in deciding on alternatives to PCB's. The capacitor ?nd transformer askarels have-different percentage contents of various PCB's, but they are both formulated from the same basic stock. They, therefore, aid each other In achieving the cost advantages of large scale production. Any shift of either market away from askarel would Influence the price of the askarel to the other use. This factor should not be overlooked in evaluating the relative cost advantages of substitutes for PCB's. GENP 006068 774717 3 I 2.1.3 References, Section 2.1 J Much of the material in this section was obtained through personal con versations with the manufacturers and users cited in the introduction. In addition to these personal communications, the following sources were found to be helpful: 1. In Re: Proposed Toxic Pollutant Effluent Standards, (EPA); testimony on behalf of: a. General Electric Co., Mr. George B. Farnsworth, March IA, 197A b. Westinghouse Electric Corp., Dr. James H. Wright, March 15, 197A 2. Statement of Electronics Industries Association, to EPA, concerning Proposed Toxic Pollutant Effluent Standards, in a letter to the Honorable Russell Train, Administrator, June 25, 1975. 3. R. H. Munch, "New Capacitor Imprgnants," IEEE, New York, Jan. 30, 1975- A. L. L. Jackson, "Industrial Organic Chemicals vs. Alternative Dielectric Fluids, IEEE Power Engineering Society, Winter Meeting, New York, Jan. 197A, Paper No. C7A 265-5. 5. "The Role of Polychlorinated Biphenyls in Electrical Equipment," General Electric Co., Schenectady, NY, Feb. A, 1972. 6. "Study of the potential impacts of the proposed Toxic Substances Control Act, as illustrated by Senate Bill S. 776," for Manufacturing Chemists Association, Washington, DC, by Foster D. Snell, Inc., June 26, 1975- 7. National Conference on Polychlorinated Biphenyls, sponsored by Environmental Protection Agency, Chicago, IL, Nov. 19-21, 1975. GENP OUbUov 774718 A 2.2 "Askarel-class." transformers 2.2,1 Description of the "askarel-class" of transformers The term "askarel" describes a broad class of fire-resistantJ Synthetic chlorinated hydrocarbon insulating liquids (polychlorinated biphenyls, "PCB's") which are used in certain special transformers, reactors and accessory electrical equipment where fire resistance is an important requirement. The askarel desig nation is used and defined more rigorously In the following standards and guidelines. IEEE Std. 76*1974 IEEE Guide for Acceptance and Maintenance of Transformer Askarel in Equipment ASTM D-2283-73 Chlorinated Aromatic Hydrocarbons (Askarels) for Trans formers (also see 0-2233*70) National Electric Code, 1975; Art. 100 (MDefinitions"), 450 (Transformers and Transformer Vaults), 460 (Capacitors). Askarel Is a fluid which is used both for insulation and for cooling. The transformer fluid must therefore exhibit proper electrical characteristics (particularly high breakdown strength and low electrical loss) and good thermal qualities (adequate viscosity, specific heat, and thermal stability). The transformer windings are completely immersed in the fluid, inside a tank which is sealed to prevent the fluid from escaping.^ The tank must be heavy walled to withstand the sudden pressure of a high current electrical fault '"Fire resistant" materials are difficult to Ignite, and when ignited burn at a slow rate. [2.2.1-- see references at end of section] 2 The high dielectric strength of the askarels. in fact allowed a reduction In the size of the transformer, compared with mineral oil. J3The amount of askarel fluid In such a transformer ranges from 40 to 500 gallons, depending on the size and rating of the transformer. GENP 006070 774719 5 within the tank. The tank is generally finned for convective heat transfer to the surrounding air, and it often has a pressure relief valve to bleed off any small but steady rise of gas pressure within the tank (as from occasional lowlevel arcing or corona). The fire-resistant character of this fluid, along with the high thermal stability and non-sludging qualities [2.2.2*1, has made it an attractive trans former insulant since.its Introduction in 1932. Its high cost relative to mineral oil has, however, restricted its use to a fairly well defined set of applications which we will call the "askarel-class" of transformers. It is for this set of uses, then, that alternative transformer fluids are being offered, and test methods and standards for these alternative fluids should therefore be responsive to these specific applications. The most Important application of transformer askarel is in network transformers, which are essential components of the electric power distribution system in high load GENFUuov density urban areas. These transformers deliver the electrical power directly e to large commercial buildings and so must be located in close proximity to the building, within, on, under or directly adjacent to the building. This close proximity to expensive, heavily-populated structures has led to the need for fire resistant electrical equipment, and askarel transformers are therefore specifically identified in the Nationat Electric Code and in many local fire codes and ordinances. The same type of fire-resistant transformer, of course, finds wide use also in non-urban applications such as industrial plants, apartment huiIdlngs. and shopping centers where the fire-resistant characteristic Is equally desirable. These transformers are generally in the 500 to 2000 KVA range, with primary voltages typically 12.8KV and secondary levels of 208V (three-phase, wye-connected). They are subject to high load and fault currents and so generally are fuse protected on their low voltage side. A fault developing within the *ReTerences, shown in brackets, are listed at thci end of each section. 774720 6 ;transformer tank itself will be cleared by the circuit-breakers at the substation. Two other special uses for askarel transformers deserve mention. These are In electric railroad and mass transit`traction equipment, and in electrostatic precipitation power supplies. The railroad application requires non-flammable equipment to prevent fire damage In case of accidents, but at the same time the electrical supply must be high-powered and compact, necessitating a liquid-cooled and Insulated transformer. ' Precipitators are used to remove particulate pollution from the flue gases In fossil-fueled electrTca! generating plants and other industrial furnace-type operations. The precipitator power supply and its power transformer must there fore be In close proximity to the furnace and the hot flue gas, and so again for fire protection purposes, askarel transformers are used. These two special uses are growing as mass transportation and air pollution control programs expand, and they now constitute ten to twenty percent of the askarel transformer demand. It Is evident from the above discussion that the "askarel-class" of trans formers can equally well be called the "fire-resistant class" of transformers. Both external fires and fires from electric arcs Internal to the transformer tank must be resisted. The askarets (polychlorinated biphenyls, PCB's) provide this resistance by generating hydrogen chloride which quenches any proximate flame. Their flash and fire points are also very high, making them difficult to ignite. These askarel fluids and the hydrogen chloride which they generate are highly corrosive materials, and so extensive special designing and Installation must be observed. Only particular, corrosion-resistant winding and tank coating materials can be used, "scavenger" materials must be present In the fluid to take up any small amounts of hydrogen chloride which are generated in normal operation and In addition the transformer room or vault must be adequately ventilated to prevent buildup of HC1 vapor. GENP w w / z 774721 7 Because of the toxicity and environmental problems of the PCB's, drains from askarel transformer Installations must also be adequately filtered so that small or large scale spilling of fluid, during filling^ testing, operation or catastrophic rupture, will be contained and not reach the ground water or navigable water systems. These special requirements of existing askarel-transformer designs and Installations are being Identified In order to have a clearer picture of the processes which will be involved In replacing the PCB fluid with an alternative. Eitner the new fluid will have to be compatible with ail of the characteristics of the existing askarel Installation, or new Installations will have to be de signed to accomodate the new fluid. These constraints will shape the requirements of testing procedures to evaluate and qualify new fluids and transformers filled with new fluids. 2.2.2 Sources and consequences of transformer tank rupture * If mineral oil or a new liquid Insulant such as silicone are to be used.as replacements for askarel In transformers, one can be sure that containment of this fluid will be a prime objective, for safety, environmental and economic reasons. In anticipation of requirements for containment tests and standards, It will be the purpose of this section to review the present state of standards, tests and understanding In the area of transformer fluid containment. Although the fluid is held in substantial drums or In the sealed transformer tank, loss of the fluid can still occasionally occur under several different circumstances: a. During transport of the fluid or of the filled transformer, b. During processing and handling of the fluid by the manufacturer or user, c. During in-service operation of the transformer, and i d. Upon disposal at the end of the unit's life. r k t r~iP i 774722 8 < Instructions for proper transport of the fluid and of the transformer are Included within the general procedures of the Department of Transportation [Reference 2.2.3; see also Section 2.5]. In addition, the following are cited as examples of the types of guidelines and standards which could be developed to prevent leakage during acceptance, maintenance, handling and disposal of transformer and fluids: a. "Guidelines for handling and disposal of capacitor and transformer grade askarels containing polychlorinated biphenyls," ANSI C107.1 * 1974; American National Standards Institute, 1430 Broadway, New York, NY 10018. b. "IEEE guide for acceptance and maintenance of transformer askarel in equipment," IEEE Std 76 - 197**, Institute of Electrical and Electronic Engineers, 3**5 E. **7 St., New York, NY 10017. These standards are discussed more fully In Section 2.2.5. The oil spill regulations developed and enforced by the Environmental Protection Agency [2.2.*+] also can serve as a model for judging the restrictions on other fluids leaking into the environment. These are .discussed In Section 2.5. A very rugged design is used for transformer tanks In order to maintain containment under most external or internal stresses. These tank designs are specified by industry standards published by ANSI [2.2.5] Tank dimensions, static pressure withstand capability and corrosion resistance are specified. These standards should be reviewed for applicability with new fluids. Rupture of a transformer tank while in service is most often due to arcing within the tank. This is a very complicated phenomenon which has been studied for many years. The following facts describe the phenomenon, Its effects, and possible controls as presented in three recent articles by Barkan et_. aj_. [2.2.6], Goodman and. Zupon [2.2.7], Nettleton [2.2.8], and Rlstuccia and Benton [2.2.91. a. The arc most often starts as a low-current, high-impedance arc between adjacent turns somewhere within the transformer windings, GENP 006074 774723 9 b. A "high proportion" [2.2.7] of transformer failures result from the gradual build up of pressure in the tank due to the gas evolved by the . low current arc. The pressure-relief valve present on most network transformers would avoid this as a cause of rupture in this important application of "askarel-class" transformers. Some users claim, however, that the pressure relief valve is more trouble than asset, and so avoid Its use. A fuse should also be used to clear these low-level faults [2.2.6]. c. The high impedance arc will grow with time to a high current fault as the arc eats away the insulation on more turns. Because the use of pressure relief valves generally prevents the type of tank rupture described in part b. above, the high current arc may be the most prevalent cause of tank failure in the network transformers. We presume that the final growth of current is rapid, so that a bubble of high pressure gas forms within the,fluid. The Barkan paper then shows that this bubble, as It expands, drives a "piston" of oil against the tank wall, momentarily overloading the wall and causing rupture. d. Techniques for calculating the peak tank wall pressure under arcing faults are presented in both the NettTeton [2.2.8] and the Barkan [2.2.6] articles, but both also point out the difficulty of this for actual tank t geometries. The static pressure relief valve is of no use here because of the rapid rate of pressure rise [2.2.3], and gas-flame venting techniques are also generally inapplicable for the same reason [2.2.81. There fs apparently a proposed revision to the ANSI transformer standard (C57.12.20-1971) for a standard transformer arc test to determine the necessary tank arc pressure withstand capability [2.2.91* GbMr w w < 774724 1 10 t. e. Further complicating the pressure calculation are the effects of energy release by burning of the fluid and of fluid products. This energy will buildup the pressure, and the pressure wave will have characteristics due to being flame - as well as arc-driven [2.2.8], f. One should not rely purely on tank withstand strength to prevent tank rupture under arcing, but rather this should be coordinated with a properly specified current-limiting fuse [2.2.6, 2.2.9], The peculiar 2 impedance characteristics of the arc prevent use of familiar I t types of fuse specifications; rather, the fuse manufacturers should recommend the proper fuse, based on the user's known voltage and fault-current levels. Protection against the high current arc is of great importance, not only because it may be the most prevalent source of "askarel-class" transformer failures but also because the arc is a high-temperature source which can Ignite the fluid or the decomposition products due to the arc. Thus, protective tests and standards must coordinate thi available temperature and energy (as for instance determined by a current limiting fuse) with the Ignition temperature and energy of the fluid and of flammable components created by the arc. The "full unit arc testing" discussed in the next section (Section 2.2.3) will explore this type of testing tn depth. It is worth noting at this point that an arc in an insulation fluid can cause a wide range of decomposition products, depending on the chemical nature of the fluid, the availability of reactant gases such as oxygen and nitrogen, and the intensity (temperature) of the arc. Products can be flammadle, explosive corrosive and toxic. As examples, arcs (or low level discharges such as corona) can decompose mineral oil Into hydrogen and hydrocarbon gases (and probably water), while askarels are said to break down to hydrogen chloride, nitrogen, carbon monoxide, carbon dioxide, and oxygen [2.2.10]. GENP 006076 774725 11 Not only can these products be directly harmful, but they can also weaken the dielectric strength of the insulating fluid and thereby set the stage for subsequent high current flashover and tank rupture. One should, therefore, seek standard procedures by which the fluid can be cleaned up at regular intervals, or after known arcing, in order to avoid future equipment failure. As guides in preparing such standards,, we should note the following procedures which are now regularly employed. a. "Scavenger" substances are mixed with askarels to take up the corrosive hydrogen chloride which is produced by occasional low level electrical discharges within the fluid. b. In spite of the presence of scavenger material, users are instructed to bubble nitrogen through the fluid immediately after known arcing in order to pick up hydrogen chloride before it can do corrosion damage. c. The IEEE standard 76--137^ suggests that moisture content and dielectric strength of askarel be regularly checked if arcing Is known to be occuring. Because of the combination of preventive measures outlined above, manufacturers and users report that present transformers of the network type experience about a .01 to .02% yearly rate of tank rupturing failures. Tests, standards, and guidelines must be prepared for new fluids in order that low failure rates will also be obtained for new transformer fluids. Even though a low rupture rate is experienced with transformers. It Is still Industry practice, generally backed by fire or environmental code en forcements, to place fluid-insulation transformers in vaults. Mineral oil units must be In fire-proof vaults [2.2.11]; askarel transformer vaults need not be fire-proof but must have adequate ventilation and drainage facilities so that spilled fluid is contained and toxic vapors do not accumulate [2.2.12]. tn u n n / I M H O 774726 * 12 2.2.3 Full-Unit Arc Testing In the early days of askarei usage a short-circuit test and an arcing test - were performed by Underwriters' Laboratories, Inc. on actual transformers filled with an askarei (General Electric "Pyranol")- Details of these tests are reported In the ULMH No. 2581 Report, dated September 29, 1934. More recently, catastrophic explosion (arc) tests with several Insulating fluids were performed by RTE Cor poration [2.2.13] 1. Underwriters' Laboratories Tests The transformers were rated 60 cycles, 5KVA, 2200-110 volts. One of these was short-circuited externally. The other was subjected, to an arcing test by being connected to a 12,000 KVA generator so as to apply 7,500 volts between the ungrounded 122-volt lead and ground, tn both cases, pressure-tight covers were provided with pressure-relief diaphragms designed tc rupture at not less than 10-12 psig. The results of the two tests were rather similar: no appreciable change in pressure was noted for approximately 2 minutes after current was supplied to the transformer. Thereafter, the pressure increased rather rapidly until the diaphragms ruptured. Large volumes of gases were liberated during the tests, but the gases did not Ignite upon application of a test flame. 2. RTE Arc Tests t Four Insulating fluids were tested:, mineral oil, Silicone DC-200 (Dow Corning), RTEMP (RTE Corporation), and an askarei (Westlnghouse Inerteen 70-30). Approximately four gallons of each fluid were used, preheated to 150C. The containers were sealed before the test, but the rupture pressure (pre sumably roughly the same In all four cases) was not specified. In each test the liquids were subjected to a massive arc discharge: 4660 to 4820 amps at GENF 006078 774727 *3 4800 volt open circuit. All four samples showed a violent flash initially, with .rupture of the container lid and wide spraying of liquids, but only mineral oil continued to burn. It is important to note that mineral oils used in transformers have flash points in the vicinity of 150C (146C minimum according to standard specifications) and fire points about 15C higher. Askarels, on the other hand, have no true flash point (so-called pseudo flash points do occur), and no fire point up to the boiling point. Silicone oils have very high flash points (about 300C)--see the section on flammability tests. RTEMP, being a high hydrocarbon fraction, presumably also has a high flash point. Thus the tests were conducted with initial fluid temperature near the flash and fire points of mineral oil, but substantially below flash points of other fluids. 3. Reaction from Industry and Insurance 4 The consensus appears to be that both sets of tests (lIL and RTE) show askarels to have very low flammability. The UL rating of 2-3 on the scale of 100 for flammable fluids reflects this consensus. Furthermore, the Factory Mutual representatives appear satisfied that the RTE tests show also the silicone fluids and RTEMP to have flammabilities in the same, generally acceptable, range as askarels. UL representatives have not consented on the RTE tests. On the other hand, the nature of the initial flash in RTE tests and of the observed pseudo flashes in flash point testing of askarels does no% appear to be understood, so some concern remains. Intense heating of the decomposition products by the arc may lead to some reaction of these products with air. Contributors have also suggested that Tn arc explosion tests of askarels the fluid Is elect rically heated to decomposition temperatures, and that decomposition itself is ftl O Q O O JKi'ar^ exothermic. As a result, several representatives from industry and insurance business have commented that a carefully standardized arcing test should be developed. Manufacturers, users, and testing laboratory personnel have Indicated a willingness to cooperate in developing such a test. 774728 14 2.2.A Alternatives to askarets in "askarel-class" transformers; influence on total transformer tests and standards We must emphasize again that the purpose of this study is not to evaluate alternatives to askarels but rather to survey the status of tests and standards by which such alternatives may be judged. The characteristics of the available alternatives must be explored, however, to the extent that unique characteristics will influence the definitions of tests and standards. This section will emphasize the effect of alternatives on the total unit, while the next section will look at standards for the fluids themselves. Many concepts originally brought up in Section 2.2.2 ("Sources and consequences of transformer tank rupture") will be revisited in terms of the goals of this section. The characteristics of available alternative fluids are presented in detail in Section 2.4 and so need not be repeated here. It is important to note, how ever, that these represent a wide range of density., viscosity, operating temper ature, corrosiveness, volatility, hydrolytic stability, flammability, etc. Because of the divers!veness of these values, we wi'11 see that universal performance specifications will be difficult to write without taking into account the unique characteristics of each particular Tnsulant. This will be equally true in establishing universal performance standards for the total transformer assembly. The important fluid characteristics which must be accounted for in any future transformer standards and specifications are listed below: a. Material compatibility. The chemical activities of the available Insulation fluids differ in kind and degree. Tests must, therefore, be devised to measure adequacy of the materials used for protective coating on inside of the tank walls,.for insulation on the wire used for the transformer windings, and for miscellaneous other components such as disconnects and fuses which might be in contact with the fluid. u c n r uuouou 7 7 4 7 29 15 b. Temperature. If the particular insulating Fluid requires an unusually high operating temperature, all materials used to construct the trans former nust be compatible with this temperature, and in addition the location of the operating transformer must be selected to be acceptable to this higher operating temperature. Existing standards such as: ,(General Principles for Temperature Limits in the Rating of Electric Equipment," IEEE Std 1-1969 are probably adequate for this purpose. Standard sampling techniques may also be desired to insure the stability of the fluids at high operating temperatures. c. Cooling. The fluid in a transformer is used as both an insulating and coaling medium. An economically competitive transformer must have its coaling system design closely matched to the characteristics of the coolant fluid, and so new fluids will undoubtedly require some redesign of the transformer. This may necessitate new standards on transformer tanks, cooling surfaces, circulating equipment, etc., and the user may demand more thorough cooling specifications on transformers with new coolant fluids. d. Hydrolytic stability. Water is generally a problem in transformer fluid, but the degree of difficulty will probably change from one fluid to another. Sealing against moisture entry, and processes for removal of water should, therefore, be specified for each new insulant. e. Containment. The different fluids will have different densities and required volumes for any given kVA and kV class of transformer, so space and supporting structure specifications must be made up for each new fluid. The types of seals will also have to be correlated with GENP 006081 774730 16 ` each fluid, since difference fluids have difference leakage character istics. Since rigorous containment of any fluid may be the goal of future regulations, standards and tests for evaluating containment of each tank/fluid combination will be of increasing importance. Standards for external protection should be coordinated with the particular class of transformers, the fluid and the level of tank containment security. By external protection, we mean secondary protection provisions, beyond the tank -itself. This Includes both vaults, for extra containment in case of tank failure and protective circuit elements (such as circuit breakers and fuses) to prevent tank rupturing arcs from occurring. Much as an electrical system has Its various power and protective elements coordinated with one another, so also might the Industry consider more quantitative coordination of the levels of transformer containment. -One might, for instance, consider that increased speed and redun dancy of circuit breaker and fuse protections could allow a less cumbersome and - * ., expansive vault structure. Extensive probability analyses of actual operating experience would be required before such a coordination plan could be.acceptable for fire codes and insurance purposes. Although no new standards or tests may be required, we Include, for com pleteness, a mention of two other available alternatives, namely dry-type and gas-cooTed transformers. These transformers depend on ambient air or special gas insulation. The dry types are available now and are being used extensively In place of askarel transformers. Relative reliability and overload capability have been questioned by some users but are quite acceptable to others, which may mean that standardized tests on these characteristics should be available to clear up such disagreements. Gas cooled transformers are not yet as readily available for substitution. Tests may be required to establish the harmlessness or the need for containing GENP 006082 774731 IT products- of arcing within the Insulation gas. Development of these tests should be guided by the extensive existing work on entire gas-insulated substations. 2.2.5 Test techniques and standards used by manufacturers and users to evaluate fluid filled transformers The transformer manufacturer and user have the following standards documents available for guidance In selecting and handling the Insulating fluid. 1. ASTM D 2283-74 "Standard Specification for Chlorinated Aromatic * Hydrocarbons (Askarels) for Transformers." This document gives detaileu specifications of the physical, chemical and electrical properties of six askarels which have, or are being used In transformers and Identifies specific test methods. 2. ASTM D 3146-75 "Standard Specification for Oxidation - Inhibited Mineral Insulating Oil for Use In Transformers and Circuit Breakers." This document gives detailed specifications of the physical, chemical and electrical properties of the oil together with approved test methods. 3. ASTM D 1040-73 "Standard Specification for Uninhibited Mineral Insulating Oil for Use In Transformers and in Oil Circuit Breakers." This document gives detailed specifications qf the physical, chemical and electrical properties of the oil together with approved test methods. 4. ANSI C 59*131-1971 "Guide for Acceptance and Maintenance of Insulating 011 In Equipment" [Also issued as IEEE (institute of Electrical and Electronics Engineers) Std. 64-1569.] The purpose of this Guide Is to assist In evaluating the serviceability of oil received fn equipment; oil as received from the refiner for filling new equipment at the Installation site, and as processed Into such equipment. It also Is Intended to assist the operator In maintaining his oil In serviceable condition. The Guide recommends standard oil GENP 006083 774 732 18 tests and evaluation procedures, methods of reconditioning and reclaiming, the level5 at which these become necessary, and the routines for re storing oxidation resistance where required by the addition of Inhibitors. 5. IEEE Std. 76-197** "Guide for Acceptance and Maintenance of Transformer Askarel in Equipment." This guide assists Tn evaluating askarel as received in transformers, reactors, and accessory equipment operated at power frequencies and Tn efforts to maintain askarel in serviceable condition. It recommends standardized tests and evaluation procedures. Methods are outlines for reconditioning and reclaiming askarel whenever necessary. 6. ANSI (American National Standards Institute) C 107.1-197**. "Guidelines for Handling and Disposal of Capacitor- and Transformer-Grade Askarels Containing Polychlorinated Biphenyls." This document gives typical physical, chemical and electrical properties of askarels used In Insulating fluids In transformer construction, details methods of shipping and handling, spells out necessary safety precautions, recommends labeling practices and.details approved dis posal techniques. It also lists organizations having facilities for analysis and for disposal and details an analytical procedure for the determination of airborne PCB's. 7. IEEE Draft "Specification for New, Unused Transformer-type Askarels." This specification covers bulk shipment In tank cars and drums of new, synthetic, nonflammable electrical insulating liquids of the chlorinated aromatic type known as askarels which are used as insulating and cooling media In liquid-filled transformers. While this specification is intendec to cover the composition and characteristics of askarels for purchase only and does not apply to liquids In apparatus, a number of discontinued types are included for purposes of Identification and historical signifies frQnonn riwqn 774733 19 8. IEEE Std. 283*1968 "Guide for Installation of Oil-Immersed Distribution i Transformers." This document suggests procedures to be followed in filling with oil those large transformers which are customarily shipped to the point of Installation without the oil. 9. A NEMA Standards Document titled "Proposal for American National Standards on Mineral Insulating 011 for Use In Electrical Apparatus" Is In the final stages of preparation. It Is Intended "to provide a functional industry standard that will assure a continuing supply of a single mineral Insulating oil that adequately meets the needs of equip ment manufacturers and oil refiners." It sets functional limits for the essential physical, electrical, and chemical properties and specifies the ASTM test methods to be used. Presumably it will ultimately replace Items 2 and 3 above. 10. Federal Specification VV-l-530a "Insulating Oil, Electrical (For Trans formers, Switches and Circuit Breakers." This standard specifies the physical properties required, establishes quality assurance provisions, and gives instructions for testing. It Identifies several ASTM docu ments as forming a part of the specification. 11. Federal Specification VV-- 1-1219 "Insulating Fluid, Electrical (Non combustible)" This standard applies to "liquid of the chlorinated aromatic hydrocarbon type (askarels) with coverage similar to that of W-1-530a. The following standards relate to the specification and performance of the transformer itself: 1. ANSI C57.12.00-1973 (also IEEE M6 2 ) "General Requirements for Distri bution, Power, and Regulating Transformers." GENP 006085 774734 20 This standard specifies (1) service conditions; (2) preferred ratings; (3) insulation classes and dielectric tests; (4) tolerances on losses, impedance, ratio, regulation and temperature rise; (5) tests; (6) such construction details as bushing class, marking of terminals, nameplate data, etc.; and (7) short circuit characteristics. 2. ANSI C57.12.90 (also IEEE 262) 'Test Code for Distribution, Power, and Regulating Transformers." This standard prescribes methods for performing the tests specified in C57.12.00-1973 (above) and in the separate transformer standards of the C57.12 series. .The test methods covered are: (1) resistance measurements; (2) dielectric Insulation; (3) losses and impedance; (4) ratio and reg ulation; (S) temperature rise; (6) Insulation power factor; (7) polarity and phase relation; and (8) short circuit calculations. C57-98, an Appendix to C57.12.90, covers Impulse tests. 3. C57.12.903-197^ (also IEEE 262A) (Draft Standard) "Distribution am. Power Transformer Short-Circuit Test Code." This code defines a procedure by which the mechanical capability of a transformer to withstand short-circuit stresses may be demonstrated. Other standards and guides In the ANSI C57 series (there are about 30) Include such documents as; C57.12.20-197^ "Requirements for Overhead-Type Distribution Transformers 67.000 Volts and Below" C57-12.21-1969 "Requirements for Pad-mounted Compartmental-Type Single-Phase Distribution Transformers" C57.12.40-1967 "Secondary Network Transformers, Subway and Vault Type (Liquid Immersed)" C57.100-197* 'Thermal Evaluation of Oil-Immersed Distribution Transformers" G E N F UUbUO 774735 21 C57.93 (also NEMA TR--5" l956) "Guide for the Installation and Maintenance of Oil-Immersed Transformers" C57-92 "Guide for Loading Oil-Immersed Distribution and Power Transformers" 4. NEMA TRl-1974 'Transformers, Regulators and Reactors" This document Identifies the ANSI transformer standards which have been approved as NEMA standards and Includes more detailed specifications regarding such characteristics as audible sound levels, external clearances between live parts, accessories, and some test procedures. 5. NEMA TRll-1967 "Small Power Transformers with 65C Average Winding Rise and Distribution Characteristics." This covers electrical characteristics and mechanical features of this class of transformers. The above are representative of about ten NEMA standards dealing with various classes of transformers. 6. UL (Underwriters Laboratories) 506 "Specialty Transformers" This standard covers requirements for air-cooled transformers and reactors for general use but does not cover oil-filled units. 7. AAR (Association of American Railroads) SM262 "Specifications for Impulse Transformer for Coded Systems Control" 8. AAR SMI65 "Specifications for Transformer, Oil-Immersed, Self-Cooled" 9. FM (Factory Mutual) 5"27 "Fire Prevention Transformers" 10. FM 5-275 "Arc-Furnace Transformers". 11. FM 14-8 "Inspection and Maintenance of Transformers" (Note: Items 7-11 above are not In hand and thus no further description Is available.) Section 2.4.2 should be consulted for designation of the standards and techniques used for specifying and measuring the various fluid material prop erties Identified In the above transformer standards. 774736 22 GENP 006087 2.2.6* References, Section 2.2 Much of the material in this section was obtained through personal con versations with the manufacturers and users cited In the introduction. In addition, the following articles are referenced In the text: 2.2.1 'Transformer askarel Inspection and maintenance guide," Monsanto Company Bulletin Mo. IC/FF-38R, revised March, 1975. 2.2.2 R. N. Sillars, Electrical Insulating Materials, IEE Monograph 14, 1973; Section 10.2.1. 2.2.3 49CFR 100-199, revised October l, 1974. 2.2.4 "Oil Pollution Prevention," Environmental Protection Agency, 38FR 34164, December 11, 1973. 2.2.5 C57.12.40; American National Standards Institute. 2.2.6. 'P. Barkan, et_. aj_., "Overpressure phenomena in distribution transformers with Tow impedance faults: experiment and theory," F 75 464-8, IEEE PES Summer Meeting, San Francisco, July 1975. 2.2.7 E. A. Goodman, L. Zupon, discussion to Barkan paper (F 75 464-8). 2.2.8 M. A. Nettleton, "Explosions due to faults In electrical equipment," Electrical Review, 25 July 1975, pp. 16-119- 2.2.9 0. J- Rlstuccia, R. E. Benton, 'Ten most-asked questions on violent transformer failure." Transmission and Distribution, January, 1975, PP. 30-31. 2.2.10 A. E. Knowlton, editor-in-chief, Standard Handbook for Electrical Engineers, Ninth Edition, McGraw-Hill Book Co., New York, 1557. 4-56T,'TF570. 2.2.11 National Electric Code, 1975; Sec. 450-24, "011-insuTated Trans formers installed indoors," NFPA, Boston, (also see Ref. 2.2.8, Sections 15-102, 4-572, 14-300). 2.2.12 National Electric Code, 1975; Sec. 450-23, "Askarel-insulated transformers installed indoors," NFPA, Boston. 2.2.13 0. A. Duckett, "Catastrophic explosion tests In Insulating fluids," RTE Corporation, Wankesha, Wl 53186, November 9* 1974. 774737 GENP 006088 2.3 "Askarel-class" capacitors 2.3.1 Description of the "askarel-class" of capacitors In Section 2.1.2, descriptions were given of the important uses of askarel- Impregnated capacitors, namely "large" ones for power factor correction on elec tric power systems and "small" industrial ones for fluorescent tube ballasts and for motor starting. These are generally constructed by winding alternate sheets of metal foil and paper and/or film dielectric In round or flattened rolls. One or more of these rolls are connected together inside a closed metal housing which is then filled with the askarel. The paper dielectric materia! has a high permittivity (c.-B), but It is dried before assembly into the capacitor, and it contains a large volume per centage of open air space. The askarel impregnates the paper, filling the air space voids. Askarel is uniquely suited to this dielectric application because its high permittivity (ep-) reasonably matches the paper, and therefore causes less nonuniformity in electrical stress. The net high permittivity and the high dielectric strength of askarel also allow for a smaller capacitor per KVA or Kilojoule rating. This combination of high dielectric constant (permittivity) and high di electric strength would be sufficient to make askarel a favorable imprgnant for capacitors. Its stabil1ty and nonflammability are additional characteristics which capacitor users have come to accept and depend upon through the many years that askarel has been essentially the exclusive capacitor imprgnant. The com ment Is occasionally made that capacitors, particularly the large power factor correction types, are generally out-of-doors or in vaults and so flammability is not an Issue as with transformer fluids. But this is definitely a minority view point, and the majority of manufacturers and users indicate that they depend on GENP 006089 774738 2k the nonflammability of askarel capacitors. More will be said about this flammability Issue In Section 2.3.3- In considering test techniques for alternate capacitor fluids, then, we can at this time Identify the following factors: dielectric constant (permit tivity, e), dielectric strength, Impregnability, flammability, and stability. Toxicity, environmental degradability and compatibility with other capacitor materials will also be added to the list In subsequent sections. 2.-3.2 Probability and consequences of rupture The rate at which the small Industrial capacitors experience a tank- rupturing failure is very low; and when one of these small capacitors fails, it there is little loss of fluid. The total amount of fluid In all small Indus trial capacitors is, however, large, as shown In -Section 2.1. In the case of the larger, power-type of capacitor, again failure rate Is low; the tank-rupturing type of failure Is estimated to occur to .1% or less of the capacitors In service per year. Generally, a capacitor will fail by an Internal arc short-circuiting the unit. Each power capacitor Is generally Individually protected by acurrent-1lmiting fuse, and this fuse will blow when the capacitor fails, leaving the capacitor-fuse unit open-circuited. Often, power capacitors are used In parallel-series connected groups, or banks, and upon failure of one capacitor In the bank, all parallel tapacftors will try to discharge through the failed unit. The current-limiting fuse limits this "In rush" current so that the other capacitors In the bank are not damaged. ** NEKA standards exist for Identifying the proper fuse to use to protect any given capacitor. These are somewhat out of date, however, so a manufacturer* GENP 006090 *ln a capacitor containing paper Insulation, 80% of the fluid Is absorbed and so will not spill out even if the can does rupture. *CP 1-1371, "Shunt Capacitors," National Electrical Manufacturers Association, New York. See also ANSI CSS-.1-1968 (IEEE No. 18), "Shunt Power Capacitors." *7 7 4 7 3 9 25 will generally provide the necessary information for his capacitors. There Is need, therefore, for a newly created set of industry-wide standards for pro tection of new capacitor designs with new types of imprgnant dielectric fluids. 2.3.3 full capacitor arc testing We have established in Section 2.2 that flammability is an important characteristic of naskarel-c1ass" transformers and that the insulating fluid has been in the past and should continue to be qualified by full transformer arc testing. We have also recognized the importance of nonflammability of.capacitors, but it must be reported that there is little documented experience or interest In arc or flame testing of capacitors. The apparent justifications for this lack of testing are the low rate of capacitor failure and the small amount of fluid in any one capacitor. Fuse protection as described in Section 2.3*2 also reduces concern for rupture and fire. In evaluating the need for full unit flanvnabi11ty testing of capacitors, * one should also keep in mind the following factors: a. New capacitor dielectric fluids generally are more flammable than askarels. b. The paper and film, which make up a large percentage of the bulk material within a capacitor,, are generally flammable. c. Power factor correction capacitors are generally used not singly but rather in large multiple-unit banks. The flame'from a single unit might be unconsequenta1, but it could lead to a dangerous, full-bank f Ire. d. Use of many capacitors in large, closely spaced banks also has another risk. Unless each capacitor is properly fused, all parallel branches of a bank can discharge through a single unit which develops an internal a m short-circuit fault. The sudden release of this large stored energy might lead to significant damage and fire. 774740 26 O OON O Manufacturers of fluids and capacitors have privately run occasional arc tests on capacitors to study flammability effects after a bank-rupturing fault. No definitely recommended format for such testing has been brought to our attention-, however, and the indication is that considerable design and testing would be required before a quantitatively Interpretable and repeatable test could be devised. Several parties involved in the manufacture and use of capacitors did feel rather strongly that such a test should be developed, however, particularly in light of the increased flammability of the new fluids. 2.3*4 Effect of alternative fluids on design and testing of the full capacitor unit. The dielectric fluid must be compatible with all other materials with which the fluid makes contact inside the capacitor casing. As In the transformer situation, the inside coating of the metal, capacitor tank must be non-reactive with the fluid. Since the fluid permeates directly to the metal foil electrodes,' either the metal and fluid must be compatible or the metal must be treated with a protective coating. In capacitors, the most serious material coordination problem is between the fluid and the insulating sheets which separate the foil electrodes. If this Is a paper, then the fluid must be able to completely impregnate the paper, leaving no voids In which corona discharges can be initiated. Although certain fluid characteristics such as molecular weight and viscosity will help to screen out obviously improper fluids, adequacy of impregnation is best evaluated finally by testing the Impregnant fluid In a true film-electrode capacitor geometry. One should be on the watch not only for immediate corona from Inadequate impregnation, but also for weakening of the dielectric strength of the fluid, which can result from the fluid dissolving impurities out of the solid insulation material. 760000 rTW3r> 774741 27 Incompatibility of a new fluid with the existing film and paper may be solved by going to new paper and film rather than by rejecting the new fluid. Thus, tests must be devised so that combinations of fluid and solid films can be evaluated on a controllable and comparative basis, and criteria for inter preting these tests must be devised so that new fluids are not rejected merely because of Inadequacies In the paper or film. The best practical combinations of fluid and solid must be compared. In the previous paragraph, we sought the best combination of impregnant and paper from a materials compatibility standpoint. It Is important, however, to also coordinate dielectric characteristics. Severely mismatched dielectric constants will cause very uneven electric stress which can lead to corona and flashover In the more highly stressed member. Thus, askarel was a good fluid to use with paper since both have relatively high dielectric constants. The plastic films which are now In use In capacitors, such as polypropylene, have lower dielectric constants and so lower e fluids can be used. Using lower dielectric constant materials means that the capacitance per unit area of electrode is less for a given electrode separation, larger area (larger capacitor size) is needed for a given capacitance, and larger voltage or size are needed for the same energy storage. Regardless of what material Is selected, -Its dielectric constant should be accurately known under actual operating conditions, and so its e should be measured with the material in the true operating electric field. This may suggest that an extension be made In the ASTM standard test for dielectric constant (0924). The size of the capacitor is Influenced not only by the fluid dielectric constant, for a given- capacitance, but also by the dielectric strength, for-a given voltage. Decreased capacitance and energy storage because of decreased dielectric constant can potentially be regained by higher dielectric strength d^ 3 0 774742 28 < materials which allow higher fields and voltages. The design of the capacitor Is, therefore, influenced by the dielectric strength (breakdown strength) of the fluid. The breakdown strength of the fluid Itself may be measured by standard test procedures, as described In Section 2.A.2. Final capacitor designs, and test capacitor geometries can be evaluated by methods outlined in Section 2.3.5* The maximum operating voltage of a capacitor is generally set by Its corona inception and extinction levels, rather than by the flashover voltage. The low current, but continuous corona discharge causes damage to solid and liquid dielectric material and therefore leads to short life and failure of capacitors even though the operating voltage may be well below the breakdown level. Detection and measurement-of corona and particularly of Its Inception extinction points are therefore extremely important in order to specify the maximum safe voltage for long life. These corona levels are not characteristic of just the insulating fluid, Itself, however, but rather of the fluid In the actual electrode config uration, Including the electrode material, the macroscopic surface conditions, and purity of the electrode/fluid Interface. An absolute measure of corona Inception for a pure, Isolated fluid is therefore of little value, and one must instead determine the inception level for the whole electrode/insulator config uration, assembled according to routines which would be followed in manufacture. Corona measurement techniques are spec Ifed Tn ASTM D 1868-73* In addition to corona, losses In capacitors result from resistive and di electric properties of the fluid. These can generally be evaluated for the pure. Isolated liquid as described In Section 2.A.2. The measurement should duplicate operating conditions (frequency, temperature, electric field) as closely as possible. Generally, higher dielectric constant materials exhibit higher loss, because of the large and rapid molecular polarization changes required by high permittivity materials In a-c fields. GENP uuoim 774743 29 A final Important character!Stic of the capacitor dielectric fluid Is Its stabllTty. It must show little change in dielectric, chemical or physical characteristics under actual electrical and thermal operating conditions over the many years expected life time of the capacitors. Frequent comments from fluids manufacturers, capacitor manufacturers and users brought out (1) the Importance of this characteristic, (2) the difficulty in defining and measuring stability, and (3) the Importance of the measurement being in as realistic an environment as possible, i.e., In a test capacitor configuration. In conclusion, this section nas shown that the particular dielectric fluid chosen for a capacitor has a major effect on the total capacitor design. Con sequently, and of more major importance to this study, we can further conclude that all aspects of hew capacitor dielectric fluids-final1y need to be evaluated In the true, operational capacitor environment. 2.3.5 Test techniques and standards used by manufacturers and users to evaluate fluid-filled capacitors and cables. * The capacitor manufacturers and users have the following standards documents available for guidance Tn selecting and handling the Insulating fluid. 1. ANSI C 59 :H (also American Society for Testing Materials (ASTM)) 02233-7*+ "Standard Specification for Chlorinated Aromatic Hydrocarbons (Askarels) for Capacitors." This document gives detailed specifications of the physical, chemical and electrical properties of four askarels which have been used as capacitor Imprgnants and details test methods. This document provides detailed specifications of the physical chemical and electrical properties of the oil. 774744 O O oOS 'O L/i 30 3. ANSI C 59-122-1970 (also ASTM D2296) "Standard Specification for Continuity of Quality of Electrical Insulating Polybutene Oil for Capacitors." This document provides detailed specifications of the physical, chemical and electrical properties of the oil and details test methods. k. ANSI C 107-1-1974 "Guidelines for Handling and Disposal of Capacitor- and Transformer-Grade AskareIs Containing Polychlorinated Biphenyls." This document gives the typical physical, chemical and electrical properties of askarels used as capacitor impregnatns, details methods of shipping and handling, spells out necessary safety precautions, reconnends labeling practices and details approved disposal techniques. It also 11sts organizations having facilities for analysis and for disposal and details an analytical procedure for the determination of airborne PCB's. 5. IEEE Draf: "Specification for .New, Unused Transformer-type Askarels" This specification covers bulk shipment In tank cars and drums of new, synthetic, nonflammable electrical insulating liquids of the chlorinated aromatic type known as askarels which are used as insulating and cooling media In.11quid-f11led transformers. While this specification is in tended to cover the composition and characteristics of askarels for purchase only and does not apply to liquids in apparaturs, a number of discontinued types are included for purposes of identification and historical significance. The following standards relate to the specification and performance of the capacitor Itself: vjciNr uuouyo 774745 31 1. ANSI C-55.1-1968 (IEEE No. 18) "Shunt Power Capacitors" Definition of terms, ratings, tolerance, operation, production and design testing, fusing. Such characteristics as stability, corona start, radio influence voltage, overvoltage, capacitance, leakage, loss and dielectric withstand are identified, but the specific detailed test technique is not described, nor are appropriate ASTM procedures cited. This standard is for shunt power capacitors without reference to the dielectric fluid; with non-askarel fluids, certain specified values and limits might possibly have to change, and specific test procedures may not be the same as have been traditionally used for askarel capacitors. 2. ANSI C 55.2-1973 "Series Capacitors for Transmission and Distribution line Compensation" This standard includes requirements for safety, rating, and gap settings; functional requirements for protective equipment, alarm devices, servicing, type, and routine tests and a guide for operation. 3. NEMA CPI-1971 "Shunt Capacitors" This standard is similar in coverage- to ANSI C 55.1. 4. EIA RS-392 "Fixed Paper Dielectric Capacitors for Alternating Current Applications." This standard covers the requirements for oil-paper dielectric capa citors hermetically sealed in metal cases for general purpose application on AC voltages. It specifies (1) standard designations, (2) standard test conditions, (3) marking, (A) quality assurance test programs, (5) tests, and (6) applications suggestions. Although the term "oil" Is used, this standard Is meant to apply to askarel-fI lied capacitors. '-J.tlJN JK u u o u y / 7 ?4746. 32 5. EIA RS-392-1 (ANSI 083.673-197*0 "Fixed Paper Dielectric Capacitors with Non-PCB Impregnant for Alternating Current Application" This standard applies to capacitors with paper dielectric impregnated with non-PCB fluid. Note that there Is no existing EIA standard covering. non-PCB capacitor fluids with plastic film dielectric. 6. EIA RS-*tOl "Paper, Paper/Film, Film Dielectric Capacitors for Power Semiconductor Applications." The coverage of this standard Is similar to RS-392 above. 7. UL (Underwriters Laboratories) 10 "Power Factor Correction Capacitors" (600V). Cables AEIC (Association of Edison Illuminating Companies) 1-68 "Solid-Type Impregnat'ed-Paper-lnsulated Lead-Covered Cable Specifications" This standard specifies rated voltages, preferred sizes, construction, and assembly details and tests. AEIC 2-67 "Specificatlons for Impregnated-Paper-Insulated Cable, HighPressure Pipe-Type". The coverage of this standard is similar to 1-68 above. IPCEA (Insulated Power Cable Engineers Association) 5~67~**01 (also NEMA WC2-1967) "Metallic and Associated Coverings for ImpregnatedPaper-lnsulated Cables" This covers materials, constructions, and requirements for metallic and associated coverings for normal use with oil-impregnated, papertnsulated power cables. This is the only IPCEA standard not related to solid insulation. Note: There are also several ANSI Standards In this area. 33 GENP 006098 2,3*6 References, Section 2.3 Huch of the material In this section was obtained through personal con versations with the manufacturers and users cited In the Introduction. In addition to these personal communicat Ions, the following publications and reports were found to be helpful: 1. R. H. Hunch, "Hew Capacitor Imprgnants,11 IEEE, New York, Jan. 30, 1975* 2. B. H. Goldy, W. 0. Solbert, "A New Liquid Dielectric for Capacitors," Insulaton/crcuts, Jan., 1975. 3* John Lapp, "Concepts In Systems Testing of Dielectrics In Capacitors," IEEE PES Summer Meeting, July, 1974, T 74 450-3. 4. J. H. Wright, "Comments of Westinghouse Electric Corporation," hearings regarding "Preposed Toxic Pollutant Effluent Standards Mar. 35, 1971*. 5* L. L. Jackson, "Industrial Organic Chemicals as Alternative Dielectric Fluids," IEEE PES Winter Meeting, New York, Jan., 1974, C74 265-5. GENP 0 0 6 0 yy 774748 34 2.1 Dielectric, and Insulating Fluids 2.1*.l A vailable F luids . In t h i s s e c tio n ve s h a ll t r e a t a few o f th e m ajor m a te ria ls used a t th e p re se n t tim e in th e e le c tr i c power in d u stry as tra n sfo rm e r and c a p a c ito r f lu i d s . The power in d u stry in g en eral has viewed w ith re lu c ta n c e any change from th e use o f a sk a re ls in tran sfo rm ers and cap acito rs not out o f p re ju d ic e o r in d iffe re n c e to th e environment o r p eo p le's sa fe ty , but because th e ask arels possessed outstanding e le c tric a l c h a r a c te r is tic s . Furtherm ore, th e a sk a re ls have low flam m ab ility , and, w hile not in ex p en siv e, t h e i r co st has b e e n .a t a le v e l th e in d u stry could manage. I t must be em phasized t h a t th e r e i s no o th e r f l u i d now a v a ila b le which has q u ite so b ro ad a ra n g e o f a p p lic a tio n and u sefu ln ess in th e e le c tr i c power in d u stry . I f i t is decided th a t th e a sk a re ls are not to be used in tran sfo rm ers and c a p a c ito rs , th en i t w ill be f a ir ly c e r ta in t h a t two c la s s e s o f compounds, one fo r c a p a c ito rs , th e o th e r fo r tra n s fo rm e rs , w ill be required. In a d d itio n to the high v e r s a til ity o f th e a sk a re ls, th e re is th e fa c t th a t th e m a te ria ls a re cheap, although th ey c o s t more than m ineral o i l s . The prime s u p p lie r o f a s k a re ls i s a major chem ical company o f high p ro d u ctiv e c a p a c ity which has kept th e p ric e o f th e m a te ria l a t a re a so n a b le le v e l. The g e n eral a p p lic a b ili ty , as w ell as th e r e l a t i v e l y low c o st w ill be l o s t in any sw itch away from a s k a r e l s , sin c e v i r t u a l l y a l l proposed s u b s titu te s w ill be more expensive. At le a s t one o f th e prom ising s u b s titu te transform er flu id s discu ssed below is a t p resen t being o ffe re d a t a re b a te , presum ably in o rd e r to e s ta b lis h a m a rk e t. I t i s n o t known w h eth er t h i s low er r e b a te p ric e could be m aintained fo r any g re a t len g th o f tim e. The m a te ria ls discussed b r ie f ly below c o n s titu te by no means a l l o f th e e x is tin g p ro m isin g f lu i d s proposed as s u b s t i t u t e s f o r th e a s k a r e ls . Any such l i s t would be immensely long and would prove to be an encumbrance to t h i s re p o rt which is designed to provide a view o f the adequacy o f p re se n t t e s t methods r a th e r th an a view o f a l l p o ssib ilities. 774749 The major flu id s proposed as s u b s titu te s for th e a sk a re ls in power tran sfo rm er and cap acito r ap p licatio n are for transform ers: (a) silic o n e o ils , (b) m ineral o i l s , U n j N r nvoiuu (c). h ig h ly sa tu ra te d p a ra ffin o i l s . For c a p a c ito rs , th e flu id s a re (d) long ch ain e ste rs of ph th alic acid and (e) d ia ry l sulfones o f a v a rie ty of types. There are o th er m inor f lu id s v h ic h w i l l be in c lu d e d a t th e c lo s e o f th e d is c u s s io n . However a t th e present tim e, th ese m aterials are e ith e r not so d e sira b le e le c tr ic a lly as the above fiv e f lu id s o r th e y a re an o rd e r o f m agnitude (o r two I) more ex p en siv e. B efore pro ceed in g to th e c o n s id e ra tio n o f th e n o n -a sk a re l flu id s a few rem arks on th e a s k a r e ls them selves may n o t be a m iss. GENP 006101 774750 36 The A sk arels (p o ly ch lo ro b ip h en y ls) The a s k a re ls a re p ro p rie ta ry m ix tu res o f c h lo rin a te d b ip h e n y ls and c h lo rin a te d benzenes, th e e m p iric a l form ulas o f which a r e C^ ^ o - n ^v^e r e -- may 111X1 fro 1 to 10)and Cg Hg n Cl^ (where 11 may ru n from 1 to 6) r e s p e c tiv e ly . These compounds may be re p re s e n te d by th e s t r u c t u r a l form ulas o f a s in g le example o f each . Cl Cl GENP 006102 2 , 2 1, U, U* - te tra c h lo ro b ip h e n y l 1 , 3,. 5 - trich lo ro b en z en e The p ro p rie ta ry m ixtures m entioned above u su a lly are desig n ated as having an e f f e c t i v e p e rc e n ta g e of* c h lo rin e and t h i s p e rc e n ta g e u s u a lly ap p ears somewhere in t h e i r tra d e num erical d e sig n a tio n . The s in g ly c h lo rin a te d b ip h en y ls a re l i g h t o i l s and th e com pletely c h lo rin a te d (n - 10) b ip henyls u su a lly assume th e c h a ra c te r o f a r e s in o r wax. A lthough f i r s t sy n th esized n e a rly a cen tu ry ago [ l ] , i t was not u n t i l th e t h i r d and fo u rth decades o f th is cen tu ry th a t th ey were produced in c o n s id e ra b le .q u a n titie s [ I t was d u rin g th e se decades th a t th e su p e rio r e l e c t r i c a l p ro p e rtie s o f th e s e m a te ria ls became a p p a re n t. W ithin a few y e a rs , la r g e s c a le m anufacture o f th e p o ly c h lo ro b ip h e n y ls was u n d e rta k e n [ 3 ] . B esides th e e x c e lle n t e l e c t r i c a l p r o p e r tie s and th e low flam m ab ili * o f th e p o ly c h lo ro b ip h e n y ls i t was observed th a t w ith th e -somewhat h ig h e r d i e l e c t r i c co n stan t over, say, transform er o i l s , th e cap acito r siz e could be reduced [U], The a sk a re l flu id s have been suggested as being s u ita b le in a wide v a rie ty o f a p p lic a tio n s o u tsid e th e e le c tr ic power in d u stry , m ostly as heat tr a n s f e r f lu id s , a d d itiv e s to petroleum o i l s , in t e x t i l e co atin g s and in su rfa c e c o a tin g s and p a in ts f5 A p p licatio n s to se a lin g compounds, p rin tin g inks and p ap ers, and c a s tin g waxes a re a l l w ell a tte ste d [5 ]. 774751 The v a rie ty and su cc e ssfu ln e ss o f a p p lic a tio n o f th e a sk a re l m ixtures has le d to widespread use and unfortunately to th e ir widespread occurrence in the environment. 37 Most o f th e a re a s where th e p o ly ch lo ro b ip h en y ls o ccu r In th e environm ent a r e , o f c o u rs e , a ss o c ia te d w ith em inently in ten se in d u s tr ia l a c ti v ity . However, th e high chem ical s ta b ility o f th e ask arels insures th e ir p e rsiste n c e wherever they are tran sp o rted . The r e s u l t i s t h a t th e y a re found a t some p o llu tin g le v e l in a g r e a t many p la c e s around th e w orld. The p o ly chlorobiphenyls have been documented as e x is tin g in Worth and South America in both marine and fresh w ater environm ents [6 -1 0 ]. A d e ta ile d d is c u s s io n o f th e s e fin d in g s may be found in K im brough's com prehensive rev iew p ap er [ l l ] . There would seem to be l i t t l e p o in t e x p a tia tin g upon th e t o x ic ity o f th e polychlorobiphenyls in th is b rie f resume sin ce th is re p o rt concerns th e adequacy o f t e s t s o f p ro s p e c tiv e replacem ents fo r th e s e v e ry f l u i d s . S u f fic e i t to s a y , in summing up, th a t th e polychlorobiphenyls accum ulate, p e r s is t, and re d e stru c tiv e to animal tis s u e s . Evidence fo r th e ir p ro sp e ctiv e condemnation u n fo rtu n a te ly mounts [ l2 - l6 ] . K im brough's review [ l l ] p ro v id es d e t a i l s on to x ic e f f e c t s in an im als and human b e in g s o f polychlorobiphenyls and should be co n su lted by th e in te re s te d re a d e r. 774752 g e n p 0001 Silicone Oils P robably th e forem ost c o n ten d e rs among th e s i l i c o n e o i l s as a s u b s t i t u t e fo r th e. a s k a r e ls a re m ix tu res o f th e d im eth y l s ilo x a n e polym ers. These m ix tu res can be made up in a v a r ie ty o f v i s c o s i t i e s . One o f th e most im p o rta n t p r o p e r tie s o f th e d im e th y lsilic o n e o ils is th e ir low tem perature c o e f fic ie n t o f v is c o s ity [1 7 ]. They a r e a ls o m ech a n ic ally r e s i s t a n t to h ig h s h e a r r a t e s [1 8 , 19] These compounds a re g e n erally in e rt and a re re s is tiv e to o x id a tiv e and therm al degradation [20, 2 l] , The d im e th y ls ilic o n e o i l s may be compounded to have v i s c o s i t i e s ru n n ing from 1 to w e ll beyond 30,000 c e n tis to k e s . The d i e l e c t r i c c o n s ta n ts f o r a l l such m ix tu res rem ain in th e neighborhood o f 2 .7 o v e r many o rd e rs o f m agnitude in freq u en cy [2 and over a broad range o f v o ltag es [2 5 ]. The flam m ab ility o f th e v ario u s m ixtures e x h ib itin g t h i s v i s c o s i t y range may be gauged by th e ran g e o f th e open cup f l a s h p o in t o f about 37 bC fo r a 1 -c e n tis to k e f l u i d to about 320 C f o r a 2 0 0 -c e n tis to k e f l u i d [2 2 , The s o l i d - l i q u i d t r a n s i t i o n s fo r th e m ethyl silo x a n e o i l s t h a t i n t e r e s t us h e r e , o c cu r f o r th e most p a r t in th e neighborhood o f -8 0 to -Uo C [2 2 ]. The d i e l e c t r i c s tr e n g th o f th e s e f l u i d s i s in th e neighborhood o f bO kV /0.1 in . [2 2 ]. The d i s s i p a t i o n f a c to r i s about 0.0003 a t 100 Hz. A ll in a l l , th e s e f l u i d s a re n e a r ly id e a l a s power tra n s fo rm e r f l u i d s . They do n o t slu d g e o r o x id iz e e a s i l y and w ith p ro p e r d e sig n one o b ta in s good heat tr a n s f e r . They o f f e r good re s is ta n c e to a cid and a lk a lin e contam inants in a tra n s fo rm e r. O f f s e ttin g th e s e v ir t u e s somewhat i s th e fa c t t h a t when th e s e f lu i d s a re s u b je c te d to a r c s t h e i r d i e l e c t r i c s tr e n g th may be reduced by th e fo rm atio n o f s o lid SiOg fila m e n ta ry b rid g in g . .In a d d itio n th e re seems to be a p o s s ib ility o f s ilic o n c a rb id e , SiC, being formed a t an arc in th ese o i l s . S ilic o n carb id e is conductive, and re fra c to ry , and provides an o th er impediment to th e s e l f healing of the d ie le c tric liq u id [2b]. These drawbacks a r e much more d e trim e n ta l to a p p lic a tio n s in c a p a c ito r s th a n in tra n s fo rm e rs and e x p la in why th e o i l s a re proposed m o stly f o r tra n s fo rm e r u se. GENP006J04 774753 39 Since th e breakdown products o f th e s ilic o n e s resem ble th e p ro d u cts from vhich they are sy n th esized , a fev words should be added here about th e chem istry o f s ilic o n e o i l s . What i s g iv en below i s n o t meant to r e p r e s e n t c u r r e n t p r o p r ie ta r y methods o f silic o n e o il production but to give elem entary background m aterial fo r discussions elsewhere inthe re p o rt. E a rly e x p ec ta tio n s th a t s ilic o n would form an org an ic chem istry analogous to carbon organic chem istry were never f u l f i l l e d . S a tu ra te d s ilic o n ch ain s analogous to th e p a ra ffin s can indeed be formed but th e s ilic o n - s ilic o n bond is r e la tiv e ly weak. At th e b e g in n in g o f th e c e n tu ry A lfre d S tock p re p a re d th e f i r s t few members' o f th e s ilic o n h y d rid e s e r ie s by dropping [see 26] a c id on magnesium s i l i c i d e : MggSI + H Cl - SiHu + Si2 Hg + Si3HQ + . . . + MgClg . He found t h a t th e h y d rid e s were u n s ta b le and he was n o t a b le t o p re p a re any compound in pure s t a t e h ig h e r th an Si^H^g [see 2 6 ]. The modern s ilic o n compounds v h ich a re o f i n t e r e s t h e re do n o t r e ly on th e S i-S i bond which i s s u b je c t to o x id a tio n b u t upon th e s t a b l e S i-O -S i bond. From t h i s bond tr u e polym ers may be c o n s tru c te d as was ev id en ced by th e thorough in v e s tig a tio n o f compounds o f t h i s c la s s by K ipping in th e f i r s t h a l f o f th e c e n tu ry [se e f o r in s ta n c e , 2 7 ]. We m ight p u rsu e one p o s s ib le p a th to s y n th e s is o f a d im e th y l s i l i c o n e . I f we t r e a t sand ('SiOg) a t about 1000 C w ith c h lo r in e gas and a red u cin g agent (carbon) an Im portant product would be s ilic o n te tr a c h lo r id e , a c o rro s iv e liq u id a t room tem p eratu re (S iC l^ ). Use o f a m ethyl G rignard re a g e n t (CH^MgCl) w i l l allo w attach m en t o f m ethyl groups to th e s i l i c o n atom: S iC lu + 2 CH^MgCl -* (CH3 )2 S iC lg + 2 MgClg . The d im e th y l s i l i c o n d ic h lo r id e i s most u s e f u l b ecau se we sim ply allo w i t t o r e a c t Vth w a te r: 774754 GENP 006105 CH3 CH3 Cl - S i - Cl + 2H2 0 + HO - S i - OH + 2 HC1 ch3 ch3 This product is c a lle d dimethyl d isH a n o i and w ill undergo a dehydrative condensation, th u s : ch3 ch3 ch3 ch3 HO C - OH + HOS i - OH -* HO r S i - 0 - S i - OH + H20 CH3 CH3 .CH3 CH3 giving us a p rim itiv e dim ethyl s ilic o n . A glance a t th e equation v i l l suggest to th e re a d e r th a t lo n g er ch ain s and c y c lic compounds can be b u ilt up from o u r sim ple s ilic o n e , and such i s th e c a s e . The l a s t r e a c tio n may be re v e rs e d under a l t e r e d c irc u m s ta n c e s , i . e . , may y ie ld s i l a n o l s from s i l i c o n e s , a p o in t o f i n t e r e s t in av o id an ce o f dumping to x ic m a te ria ls onto th e land and in to waterways o f th is country. These compounds a re non-flammable in th e sense th a t th e y have no tr u e com bustion p o in ts . The h e at su p p lie d to th e compound must be s u f f ic ie n t to cau se d e p o ly m e riz a tio n i f th e combustion is to be su stain ed ; only th e sh o rt chain polymers r e a lly burn [25, 2 8 ], GENP006I06 774755 Ul Mineral Oils Most o f th e o i l s used as tra n s fo rm e r f l u i d s a re complex m ix tu re s o f p a r a f f in ic compounds o f m in e ra l o r ig i n . Many o f th e s e p a r a f f i n i c compounds a r e b o th s a tu r a te d and c y c lic . Such compounds a re d e sig n a te d as "n ap h th en ic" by th e petroleum in d u s try . The o i l s a re n e a rly always th e r e s u l t o f a p ro c e ss v h ere th e r e f in in g method i s ta ilo r e d to th e f in a l use o f th e p ro d u ct. The arom atic c o n ten t o f th e o il must be c o n tro lle d in order to prevent sludging or o x id atio n o f th e p a ra ffin components; but some a ro m a tic s a re added as o x id a tio n i n h i b i t o r s . A t y p i c a l a d d itiv e which i s compounded w ith th e o i l as an a n tio x id a n t i s d i t e r t i a r y b u ty l p a r a c r e s o l (DTBF) which fr e q u e n tly i s added a t th e 0,2% le v e l [2U]. Such a n tio x id a n ts a r e l a r g e l y c o n fin e d to d i s t r i b u t i o n tra n sfo rm e r a p p lic a tio n s . The use o f such compounds i s la r g e ly avoided in power tran sfo rm ers where th e flu id i s h e rm e tic a lly sealed in to th e tran sfo rm er under a b la n k e t o f n itro g e n g as. The a d d itio n o f aro m atic compounds i s a ls o designed to i n h i b i t .ssin g in an o i l under th e o p e ra tin g c o n d itio n s o f a tra n s fo rm e r. However such a d d itio n s may .prove a tw o-edged sword s in c e ohe and 'th e same c l a s s o f compounds can cause sludging and oxidation of th e p a ra ffin o i l . The low c o st and s e lf -h e a lin g p ro p e rtie s o f m in eral o i l s coupled w ith th e ir s a tis fa c to ry e le c tric a l p ro p erties have contributed to th e ir widespread use. These o ils have a d ie le c tr ic con stan t of about 2 . The d is s ip a tio n f a c to r i s about 0.001 a t 60 Hz. The d i e l e c t r i c s tr e n g th o f m in e ra l o i l s i s g e n e r a lly g r e a te r th a n 30 kV /0.25 cm,, aid 10^2cm i s a ty p ic a l value fo r th e r e s i s t i v i t y o f a f t e s h o i l . The t o x i c i t y o f o i l s composed e n tir e ly o f sa tu ra te d p a ra ffin s i s v ery low. H ighly s a tu ra te d o i l s fin d p e re n n ia l u se in cosm etic p ro d u c ts . Some o f th e h ig h ly r e f in e d o i l s a re pharm acopoeal. The p re se n c e o r a d d itio n o f aro m atic i n h i b i t o r s in c r e a s e s th e t o x i c i t y o f th e o i l s . The degradation o f a pure o i l in a normal atm osphere probably follow s the course of o x id a tio n of alkanes to , u ltim a te ly , carbon dioxide and w ater. Such a process ould req u ire high-energy ra d ia tio n (u ltra v io le t) fo r in itia tio n o f the reactio n . GENP 006107 774755 - U2 The mechanism o f th is process is not y e t c le a rly understood because o f th e p a u city o f knowledge o f slow r e a c t i o n s .[3 1 ] A ll p a r a f f in s a re to some s l i g h t e x te n t s o lu b le in w a ter and can th e r e f o r e in tim e r e a c t w ith compounds p re s e n t in n a tu r a l w a te rs. F u rth erm o re , v o l a t i l e f r a c tio n s o f an o i l may escap e in to th e atm osphere where i f th e y a r e e x c ite d by e n e r g e tic r a d i a t i o n th e y may form f r e e r a d i c a l s which r e a d ily re a c t w ith atm ospheric components. Whatever th e d e ta ils o f th e case , i t is b eliev ed th a t th e d eg ra d atio n p roducts w hether produced by p h y s ic a l o r b io lo g ic a l means a re not h ig h ly damaging to th e environm ent. The flam m ability o f the m ineral o ils is considered high since they are hydrocarbons w ith no quenching atoms (su ch as h a l i d e s ) . I f th e o i l i s to be s u i t a b l e fo r tra n sfo rm e r use i t must be both in s u la tin g and non-viscous a t o p eratin g tem p eratu res s in c e i t w i l l be used as a c o n v e c tiv e h e a t t r a n s f e r f l u i d . However in a rough and re a d y way o f s p e a k in g ,th e le s s v isc o u s an o i l , th e c lo s e r i t i s to i t s f l a s h p o in t so t h a t a compromise between hazard o f f i r e and e ffic ie n c y as a h eat exchanger is re q u ire d . These c o n sid e ra tio n s have lead power companies to th e use o f o i l in tran sfo rm ers and c a p a c ito rs almost ex clu siv ely in e x te rio r in s ta lla tio n s , and even th e re a fire w a ll may be re q u ire d (a s n e a r a wooded a r e a , f o r example) o r a d v is a b le . I f a tra n s fo rm e r can be made to o p e ra te a t a te m p e ra tu re rem ote from i t s f la s h p o in t th e h azard from f i r e would seem to be more rem ote th a n ' in th e u s u a l s i t u a t i o n . There i s some advocacy (se e f o r example D uckett RTE C o rp ., [3 0 ]) o f u sin g h ig h - p u r ity h ig h - f la s h - p o in t p a r a f f in o i l s in in s id e i n s t a l l a t i o n s , much as a s k a r e lJ a re used a t p re s e n t. The t e s t used .to su g g est th e s u i t a b i l i t y o f such o i l s is d iscu ssed in th e next section. GENP 006108 774757 1*3 Hydrogenated P a ra ffin O ils One su g g ested f lu i d f o r tra n s fo rm e r u se i s a p ro d u c t which th e RTE C orporation of Waukesha, W isconsin i s o ffe rin g as a s u b s titu te fo r a sk a re ls in tran sfo rm ers In locations proxim ate to or in s id e b u ild in g s. The firm m ain tain s th a t th e high fla s h p o in t and consequent low flam m ab ility of t h i s o i l so much reduces hazard from f i r e in p ro x im ate i n s t a l l a t i o n s th a t th a t flu id should q u alify fo r serv ice in such in s ta lla tio n s . T h is f l u i d i s n o t produced by th e RTE C o rp o ra tio n i t s e l f . The s u p p lie r i s a la r g e o i l company [29] and th e f l u i d was d e sig n e d , o r expected to be u sed , in h ig h -te m p e ra tu re tra n s fo rm e rs . The p ro d u c t i s m arketed as RTemp. The co m position does n o t appear to be a n y th in g u n u su al in th e way o f p etro leu m o i l s . I t i s a h ig h -v isc o sity 800 cs (25C), h ig h -fla s h -p o in t (296C) o i l w ith a d i e l e c t r i c s tr e n g th o f ab o u t 37 kV /0.25 cm, (ASTM D 877), and high r e s i s t i v i t y , 1013 ohm-cm. The o i l I s a p etro leu m p ro d u c t tw ice s u b je c te d to a hydrogenation process, thereby acquiring i t s satu rated p a ra ffin ic p r o p e r tie s . RTemp i s th e r e f o r e a h ig h ly s ta b l e m in e ra l o i l which i s claim ed to be of food grade [30]. I t Is presumed th a t th e environm ental c h a r a c te r is tic s of th is h ig h ly sa tu ra te d o i l would be s im ila r to th e pharmacopoeal m ineral o i l s [3 0 ]. That i s , they form " sa fe " combustion and d eg rad atio n p ro d u cts. RTemp o i l i s b ein g te s te d by power companies in th e Chicago a re a as noted elsew here in th is re p o rt [29]. The g en eral p h y sica l and e le c tr ic a l p ro p e rtie s of th is o i l resem ble the ordinary tran sfo rm er o i l s . The flam m ability p ro p e rtie s o f R Temp tra n s fo rm e r o i l a re b e t t e r than most tra n s fo rm e r o i l s as would be in d ic a te d by I t s high fla s h p o in t. The expected low er flam m ab ility is confirm ed in a g e n e ra l way by th e s u r g e - c e ll t e s t s conducted a t RTE C o rp o ra tio n by D uckett ejt a l [3 0 ]. The su rg e o f e l e c t r i c en ergy In to th e o i l caused GENP 006109 774758 Uk v a p o riz a tio n o f th e o i l and d is p e r s a l o f th e o i l o u ts id e th e t e s t a p p a ra tu s . No f i r e r e s u l t e d , however, b ecau se th e te m p e ra tu re o f th e l i q u i d o i l was w ell below th e combustion p o in t. This behavior was In marked c o n tra s t to an o rd in a ry tra n s fo rm e r o i l s u b je c te d to th e same t e s t wh4ch I g n ite d Im m ediately and did no t e x tin g u ish p o ssib ly because o i l was I n i t i a l l y c lo s e r to i t s f la s h p o in t th a n th e RTemp and c o n s id e ra b le l e s s energy was re q u ire d to b rin g the tran sfo rm er o i l to combustion tem perature. O ils o f the highly sa tu ra te d type a re used in cable and underground a p p lic a tio n s . The high v is c o s ity o f such o i l s makes them a c c e p ta b le a t th e common o p e ra tin g tem p eratu res o f tra n s fo rm e rs In tem p erate o r even m o d e ra tely cold w eather. But In the sev erest cold these o ils req u ire the p ro te c tio n o f e n c lo s u re d r b u r ia l to m a in ta in t h e i r f l u i d i t y . A lthough th e RTE s u rg e t e s t s show,, and th e com bustion d a ta p r e d i c t th a t th e s e h ig h ly s a tu r a te d o ils are probably safer than ordinary transform er o ils , the N ational E le c tr ic a l Code Committee w i l l need Independent t e s t i n g b e fo re e x p l i c i t a c c e p ta n c e o f this fluid. 0^900 774759 1*5 M ixtures Containing D iaryl Sulfone These compounds a re proposed by one of th e m ajor chem ical companies o f th e country as s u b s titu te s fo r th e a s k a re ls . The b a sic chem ical s tru c tu re Is: vhere the R Is an a lk y l group w ith probably 1 - 8 carbon atom s, n runs from 1 to 3 and Ar I s a phenyl, n aphthyl o r indan group. A ll th e se compounds a re halogen f r e e [35]. The a c tu a l p ro d u ct Is presum ably a p ro p rie ta ry m ix tu re o f such compounds and o th e r I n g r e d ie n ts such as n o n -c h lo rin a te d b ip h e n y ls . C ite d as example In German and U .S. P a te n t d is c lo s u r e s [35] Is a m ixture of to ly l x ylyl su lfo n e, isopropylblphenyl and m inor In g red ie n ts. I t Is presumed th a t In use f u r th e r In g re d ie n ts w i l l be added to th e se compounds as antioxidants. The m ix tu re s as proposed have a d i e l e c t r i c c o n s ta n t o f ab o u t 6. No d ie le c tric strength figures are available at present, but lif e - te s ts of cap acito rs are co n tin u ally being run by th e m anufacturer of the' flu id [3 6 ]. The f l u i d Is te s te d in b a l l a s t - c a p a c i t o r u se a t 1000 v o l t s a t 90C w orking te m p e ra tu re . The f la s h p o in t o f th e m ix tu re s now ad v o cated by th e m anufacturer Is about 150C, combustion is su sta in e d a t about 1654C and the f l u i d w i l l a u t o - l g n l t e in th e re g io n o f 450C. No p o u r-p o in t f ig u r e I s a v a ila b le b u t th e c a p a c ito rs fu n c tio n w e ll a t -50*C [3 6 ]. Some t o x i c i t y s tu d ie s have been conducted by th e m a n u fa ctu rer. These s tu d ie s In d ic a te th a t I r r i t a t i o n can be Induced by In te n s e o r prolonged c o n ta c t of th e m ixture w ith eye or s k in o f ro d e n ts . The m a n u fa c tu re r recommends t h a t normal 774760 U6 \ l\900 In d u s tria l hygienic precautions be taken (a tta in a b le , In the main, w ith soap and w ater) In order to assure s a fe handling. These m a te r ia ls when fe d to ro d e n ts seem to b re a k down in to e x c r e ta b le m etab o lites according to s tu d ie s conducted by, or on o rd er o f, th e m anufacturer. Folychlorobiphenyls fed under s im ila r co n d itio n s p e r s is t In the animal body a f t e r th e sulfo n e m ixtures in th e tis s u e have become u n d e te c ta b le .* * 774761 G B t t P 006 H 2 The P h th a la te E ste rs The p h th a la te s can be o ffere d Im m ediately a s a product f o r use In th e high v o ltag e c a p a c ito r In dustry because they a re alread y supplied by the petroleum Industry as p la stic iz e rs fo r polyvinyl chloride p la s tic s In tonnage q u a n t i t i e s . In 1972, about 1 b i l l i o n pounds o f some 20 d i f f e r e n t p h th a la te e s te rs were manufactured [32]. The su p e rio r e le c tr ic a l c h a r a c te ris tic s o f th e e s te rs of p h th a llc acid make them n a t u r a l c a n d id a te s as s u b s t i t u t e s f o r th e a s k a r e ls in pow erc a p a c ito r use should the s u b s titu tio n become n ecessary . The p h th a llc anhydride ty p ic a lly Is m anufactured from naphthalene which Is o x idized in the presence of vanadium oxide to p h th a llc anhydride o r a l t e r n a t i v e l y from o-xylene by a s im ila r o x id a tio n p ro c e ss to th e same end product GENP 006113 The p h th a la te e s te rs supplied as high v o lta g e In s u la tin g liq u id s a re m ostly d lls o n o n y l p h th a la te (DINF) and d lo c ty l p h th a la te (DOP) [3 3 ]. One m ajor m a n u fa ctu rer p r e f e r s DIN? over DOP becau se o f th e expected r e s i s t a n c e to h y d ro ly sis bestowed by s t e r l c h in d ran ce. The chem ical and petroleum companies use v a rio u s methods fo r producing th e a lc o h o ls from which DOP and D10P a re form ed, a l l o f which s t a r t from petro leu m r e f i n e r y p ro d u c ts . They may be t y p i f i e d by th e one r e a c tio n fo r 774762 1*8 2. e th y l-h e x a ra l which begins v le h propylene to from a aldehade which In tu r n by a ld o l cond en satio n y ie ld s a ald eh y d e. The Cg ald eh y d e Is hydrogenated to 2 ethyl-hexanol. a ld o l aldehyde c o n d e n sa tio n * Cfl aldehyde H 2 2 ethylhexanol. The 2-ethylhexanol then e s te r lf le s the p h th a llc acid 0 p ro d u c in g th e w ell-know p l a s t i c i z e r 2 e th y lh e x a n o l. The o c ta n o ls and iso n o n an o ls used In th e m anufacture of I n s u la tin g f lu i d s w ill use the same o r s im ila r re a ctio n s In th e ir preparation. The arom atic d ib a sic p h th a la te e s te r s ty p ifie d by d ilso n o n y l and d io c ty l p h th a la te have s p e c if ic r e s i s t a n c e s In th e neighborhood o f 1012 ohm-cm. In ap p licatio n s as capacitor flu id s they o ffe r a d ie le c tric constant of about 5 which Is considerably higher than th a t o ffered by the a s k a re ls , and should th e re fo re allow fo r more compact d e sig n o f c a p a c ito rs than th e a s k a te ls . The v o lta g e breakdown p o in t o c cu rs a t around 30 k v /.2 5 cm. The b o ilin g p o in t a t reduced p re s s u re (5 mm Hg) I s ab o u t 250*0, and y e t th e po u r p ^ ln t I s In th e neighborhood o f -5 0 aC. The fla s h p o in t as d eterm in ed by th e C lev elan d Open Cup Method f o r th e s e f l u i d s I s In th e neighborhood o f 220C and th e same d e te rm in a tio n s show t h a t com bustion i s s u s ta in e d a t 250C or thereabout [34]. GENP 006114 774763 1*9 The d ib a sic p h th a la te e s te rs a re a v a ila b le on th e market ap p aren tly In any q u a n tity d e s ir e d and a re m arketed by a t l e a s t two m ajor chem ical companies* At le a s t one high v o lta g e equipment m anufacturer has m odified the design of h is power c a p a c ito rs to accomodate th e p h th a la te s as capacitor flu id s [33]. A lkyalated Chlorodiphenyl Oxides (This sec tio n is s t i l l In p rep aratio n - - w ill be forwarded to review ers at a la te r date.) GENP 006115 ,7 7 4 ^ 4 50 21{.*2 Tost techniques and standards by which fluid material properties are evaluated I n s u la tin g f l u i d s f o r tra n s fo rm e rs and c a p a c ito r s a re commonly t e s t e d and ev alu ated in accord w ith one o f th e follow ing: 1 . ANSI C 59-2 ( a ls o ASTM D117) " S ta n d a rd Methods o f T e s tin g E l e c t r i c a l Insulating O ils" 2. ANSI C 59-62 ( a ls o ASTM D901) " S ta n d a rd M ethods o f T e s tin g A sk a re ls " 3- ANSI C 5 9 -118 ( a ls o ASTM D2225) " S ta n d a rd M ethods o f T e s tin g S ilic o n e F lu id s for E lec tric a l Insulation" The t e s t p ro ced u res c a lle d out in th e s e documents a re ta b u la te d below.. A cid ity , Approximate A cid ity , Approximate, and P olar Contam ination C o e ffic ie n t o f Thermal Expan sion C o lo r C hlorides, Inorganic C hlorine Compounds, H ydro ly zab le D ie le c tric Constant D ie le c tric S tren g th Using M etal Disk E lectro d es D ie le c tric S tren g th Using VDE E le c tro d e s 2 ,6 -D itertiary-B utyl Para- C resol Content Exam ination, V isual Flash Point F ire Point Gas C ontent Gas C ontent (.N onacidic) Inorganic C hlorides and- S u lfa te s In te rfa c ia l Tension N e u tra liz a tio n Value ( N e u tr a liz a tio n Number) O xidation S ta b ility P eroxide Number Pour Point ASKABELS (D901) D971* D1903 D2129 D1821 D120, D2U1*1 D92U D877 D92 D97b, D6U D97 ELECT. INS. OILS (D117) D153U D1902 D1903 D1500 D878 SILICONE FLUIDS (D2225) D2129 D87T D l8l6 D1U73 D1524 D92 D83I DI827 D873 D971 D66U, D971* D2UhO# D1563 P97 N10O D92U. D92 D971* D97 51 (JtlJN K W OI lu ASKARELS ELECT. INS. OILS SILICONE - FLUIDS Power F acto r R efractiv e Index (and S p ecific O ptical D ispersion) R esistivity Sam pling S a p o n if ic a tio n Humber Scavenger Content Sediment and Soluble Sludge Sludge Specific G ravity Specific R esistance S u lfu r, Corrosive rhermal S ta b ility V iscosity ' V isual Examination Volume o f O il H ater Content D92U D1807 D119 D923 D1701 D1810 D1936 D88, DUU5 D1702 D108 D1533 D92U D1807 D1169 D923 D91* D1698 D1313, D1311* D129S D1275 D88, DU1*5, D 2l6l D1315, D1533 D92U D1807 D129S D II69 DUU5, D2I61 * D2112 a ls o d e a ls w ith o x id a tio n s t a b i l i t y and i s c a ll e d o u t in D31^6, " S ta n d a rd S p e c if ic a tio n f o r O x id a tio n -in h ib ite d M ineral O il f o r Use in T ran sfo rm ers and C ircuit Breakers" rhe fo llo w in g ASTM S ta n d a rd s have r e c e n tly a p p ea re d : 03300 "S tan d ard Method o f T est fo r D ie le c tr ic Breakdown V oltage o f I n s u la tin g O ils o f F etrolium O rigin Under Im pulse C onditions" 03303 "S ta n d a rd Method f o r Rapid Gas C hrom atographic E stim a tio n o f H igher B o ilin g Homologues o f C h lo rin a te d B iphenyls f o r C ap acito r A sk arels" 033OU "S ta n d a rd Method f o r A n a ly sis o f E n v iro n m en tal M a te ria ls f o r P o ly c h lo r in a te d B ip h e n y ls" (T h is document i s a m o d ifie d v e rs io n o f Appendix B o f ANSI -C107-1-197*0. GENP 006117 774766 52 1 2.4.3 Test techniques by which fluid flammability Is evaluated. Host would agree Chat the concepts of combustion and flammability of a mater ial are qualitatively clear and easily understood. The quantitative definitions of flammability of the material, that is, whether It will ignite and then continue to burn under specified temperature, pressure and ambient atmosphere conditions Is not, however, as easily achieved. What Is required Is a flammability test In which all relevant parameters are rigorously controlled and in which the results are unequivocally Interpretable, and this has been difficult to develop to every one's satisfaction. The various tests which are recognized anu in common use are described below, along with comments on their applicability and shortcomings: a. Flash and fire points The only test specified by the standard-setting agencies (ASTH, ANSI, NFPA, IEEE) for insulating fluids, mineral oils and askarels. Is the Cleveland Open Cup test for flash and fire points (ASTH D--92). The specifications are: Mineral oil: flash point of 146C (In some areas 130C); Askarel: no fire point up to boiling point. Beside the D-92 test, ASTH recognizes several other variants for deter mining the flash point, which, however, are not prescribed for Insulat ing fluids: the Tag Open Cup tester (D-1310), the Tag Closed Tester (D-56) 1 and the Pensky-Martens Closed Tester (D-93). In all experimental arrangements the flash point Is determined by slowly Increasing the temperature of the cup containing the liquid sample. An Ignition source, placed above the surface of the liquid, is actuated at specified Inter vals. The flash point, by definition, Is the lowest temperature of the cup at which the vapors above the liquid surface flash. The flashes are transient, because only the vapor phqse burns, not the liquid. In 774767 9TTQ00 rIM30 addition to the determination of the flash point, the D-92 test specifies the procedure of increasing the temperature beyond the flash point up to the temperature at which transient application of the Ignition source causes continued burning of the liquid. The lowest temperature at which this happens Is the fire point. Determinations of flash and fire points give valuable indications of flammability hazards, and should continue to be used. However, it must be recognized that developments in recent years have prog ressed significantly beyond the stage at which the standards for insulating fluids were set, and also beyond the state-of-the-art prescribed by officially adopted ASTM standards. The following items should be considered before flash, and fire point standards are recommended for replacement fluids: (1) There has been a general trend toward closed-cup methods (e.g., 0-93)- In particular, Underwriters' Laboratories have favored closed-cup tests for some time now. These generally give lower flash points than the open-cup variants. For example, the flash points of the Dow Corning 50CS (silicone) fluid are 30*tC and 277*C as determined by D-92 and D-93 tests respectively. (2) The ASTM Flash Point Committee is moving toward recommending International adoption of an "equilibrium" method. Equilib rium methods specify Flash-No. Flash determination at a series of constant (rather than continually increasing) temperatures. Since In equilibrium methods the entire system, sample and container, Is at the same temperature, complications assoc iated with heat transfer between the sample and the container are eliminated. Therefore sample size Is arbitrary and much GENP 006119 774768 5U smaller samples can be used. In addition, these methods do not depend on viscosity because convective currents within the sample are also eliminated. (3) Scientific analyses of fire-point determination are poorly . developed. Therefore, the significance of the test Is not clearly understood. This point will*be further discussed in connection with the Oxygen Index test. b. The Oxygen Index Test In the Oxygen Index (Ot) test the test sample Is placed inside a tube containing a mixture of oxygen and nitrogen gases. The gas mixture, normaliy at room temperature, flows gently upward. The sample Is ignited and the percentage of oxygen In the gas mixture Is decreased. 01, by definition, Is the percentage of oxygen in the oxygen/nitrogen mixture at which extinction occurs. e The specified ASTM 01 technique applies to solid samples only (0-2863). Various laboratories have, made their own modifications of the test to apply it also to itquids, and have reported the resulting data, but there is no uniformity of procedure. Sharply divided opinions exist as to the value of the 01 test toward a definition of flammability. For example, a limited polling of the Industrial opinions In this survey shows that some manufacturers use tie test for practical purposes, while others consider It "worthless." The reasons for this division are not difficult to see. On one hand, it Is recognized that the burning of a small laboratory sample (grams) In room-temperature environments In no way simulates the behavior of large amounts of combustible materials In a w e 11-developed fire. On the GENP 006120 774769 55 other hand, there are reasons why the 01 test should not be discounted in the context of this survey. Fundamentally, the test Is the proto type of extinction of a diffusion flame, and It bears roughly the same relationship to practical fire-point determinations that the fundamental flammability-limit data do to practical flash-point determinations. As i was discussed earlier, both flash and fire points are specified standards for definition of flammability of Insulating fluids. The problem is, however, that fundamentally meaningful fire-point, or 01, tests are more difficult to design than the meaningful flash-point tests. To obtain consistent extinction data one would have to develop an Ot test for liquids and a fire-point tester in such a way that an 01 value of 21 (i.e., air) is obtained at tho experimental fire point. Recent work at the NBS Center for Fire Research shows that such development would require very careful design of the test geometry. Therefore, an * 01 test for Insulating fluids should be recommended only after some additional study, allowing specifications of the testing arrangement. c. Spray Flammability Tests The ASTM Hist Spray Flammability of Hydraulic Fluids test (D-3H9-72T) could be applied also to electric insulating fluids, but we have no evidence that anyone has done that. The test Is a very severe one, entailing the spraying of a preheated atomized mist into an open flame. UnderwrIters1 laboratories consider It too severe and use one of their own variants In Its stead (UL File HH 01466, p. Tl-6). The UL test consists of applying drops of the liquid to the surface of a heated steel plate, and observing the "behavior." 774770 56 GENP 006121 Factory Mutual Research Corporation has Its own spray flammbl1Ity test, akin to D-3119. It Is also a very severe one. Host hydraulic fluids do not pass It. Inasmuch as our survey of actual or potential accidents (admittedly a very limited one so far) has revealed no practical circumstances which would be simulated by any of these droplet-combustIon tests, there Is no reason why they should be recommended for replacement fluids. Further survey of accidents may give ground for a firmer recommendation. Autoignition Temperature (AIT) Several techniques exist for the heating of liquids in air until they Ignite. ASTM 0-2155 Is a specified procedure for liquid petroleum products. Underwriters' Laboratories use a similar test of their awn. As one should expect, autoIgnition temperatures of electric insulating fluids are quite high. Some reported values are: 332C for a mineral oil and 393C for Dow Corning 50CS fluid, both by the D-2155 test; 662-670C for askarels by the UL test. As in the case of the spray flammability tests, operational conditions, normal or abnormal, are unlikely to give rise to these temperatures In the case of Insulating fluids. The AIT test, therefore, does ^iot appear particularly pertinent. (At this point, It should be mentioned that Underwriters' Laboratories do not evaluate liquids only on the basis of tests which simulate some aspects of actual operations, but also on the basis of the total Information about stability and flammability of the liquid. If this philosophy is adopted, then of course the AIT test and any other reproducible test which can be tied to some property of the liquid, becomes pertinent. In fact, UL did use the AIT test among others, to arrive at a numerical flammability rating of askarels). 774771 57 t t nfkft / N J 3 0 e. Energy-Release Tests Hazards tests designed to evaluate the amount of explosive energy released in an accident apparently have not been used in connection with Insulating fluids, but there are good reasons why they should be. Such tests almost Invariably give a measure of energy release by the effect on the surroundings: damage to a target, displacement of a target, or generation of a blast wave in air. Since the hazard of an arc-initiated fire In a transformer or capacitor tank may be due to the blastwave damage as well as the subsequent fire, a measure of the explosive energy release capability of an insulating fluid would appear to be useful. Such a test would be particularly important if it could be shown to be a useful screening mechanism before going to the more expensive, full-unit tests suggested in Sections 2.2.3 and 2.3*3> Direct measurement of the blastwave intensity may be the most valid energy release test, as described more fully*Tn Section 3* The accompanying Table summarizes presently accepted flammability data on several insulating fluids. GENP 006123 774772 58 FLAMMABILITY DATA (I) Info; Source Liauid D escription F lash (C) F ire (C) AIT 01 ASTM S tand. Bu Mine Dow Corning 1974 IEEE M ineral O il Min. O il, p a r a f f in ic (deep waxed) Transformer O il (ASTM D92) " D2155 " D2S63 (Mod) 146 (130) 196 150 -- 221 165 371 332 15. J ASTM S tan d . UL (c lo s e d cup) Bu Mine Dow C orning 1973 Doble A skarel No f i r e p t . up to b .p . A roclor 1016 174 -- A roclor 1242 (T rich lo ro d ip h en y l) A ro clo r 1254 (T etra- ) 177 193 334 None A skarels "have no crue fla s h p o in t." 670 Dow C orning 1 9 7 4 .IEEE UL Dow C orning 1973 Doble Bu Mine S ilic o n e s 50 CS (P o lydim ethyl) Dow C 50CS c lo s e d cup XF-1-4701 Phenylmethyl (Si) Dimethyl (h i v is e .) " (low v is e .) Methyl phenyl Polymethyl (low v is e .) 304 277 304 319 138 271 124 360 393 445 138 GENP 006124 - 774773 59 FLAMMABILITY DATA (II) 1. UL C la s s if ie d Prod. Index a ls o g iv e s in f o , on combust i b i l i t y in a i r . Dow Corning 50CS: M oderate in a i r 257C XF-1-4701: " " " 256C Compare fla s h -o p e n : 304C, c lo s e d : 277C A ro clo r 1016: M oderate in a i r 144C 2. Dow C orning, 1974 IEEE Paper Transf. O il 50CS Burning ra te (gm/sc) M ist Spray (D3119) 0.0267 V iolent 0.0060 Spasmodic 5 Z l 9 0 ci H a o 774774 60 Fluid flammabllIty measurement, by whatever test procedure Is adopted, should be carried out under conditions as closely approaching operation as reasonably possible. In particular, pressure and temperature condttons are known and should be duplicated. Thus, power transformers of the "askarel class" have a temperature Increase of about 65*C under full load, so that bulk fluid temperatures will probably not exceed 100C even on hot days. Local temperatures near the transformer winding may be ten to twenty degrees higher. Host utilities operate their transformers with a pressure relief valve as pre scribed by the National Electrical Code (Section *50-23); the relief pressure * Is usually only a few psl. Power capacitor tanks rupture at low (a few psi) pressures but small Industrial type capacitors generally are sealed to *0-50 psi. The fluid temperatures within capacitors would not be much above the ambient, which Itself might vary widely depending on location. For a new fluid, with different loss and heat transfer characteristics, these typical values may have to be revised. GENP 006126 774775 6l 2.U.1* T e?t te c h n iq u e s by v h ich t o x i c i t y i s e v a lu a te d (T his sec tio n is s t i l l in p rep aratio n --w ill be forwarded to review ers at a la te r date). 2.U.5 Test techniques by vhich d e g ra d a b ility is evaluated (This sectio n is s t i l l in p rep aratio n --w ill be forwarded to review ers at a la te r date). GENP 006127 774776 62 2 .4 .6 References fo r Secclon 2.4 2 .4 .1 Schmidt, H ., and S ch u ltze, G .v (L ie b ig 's ) Annalen, 1881, 207, 238. 2 .4 .2 Penning, C. H ., In d . Eng. Chem. 1930, 22, 1180. 2 .4 .3 C la rk , F. M., In d . Sag. Chen. 1937, 2 9 , 698. 2 .4 .4 C lark, F. M., T rans. E lectro ch en . Soc. 1934, 65, 59. 2 .4 .5 B ro a d h u rst, H. G ., E n v iro n . H e a lth . P e rs p e c t. 1972, 81. 2 .4 .6 H olden, A. V ., N a tu re , 1970, 228, 1220. 2 .4 .7 Koeman, J . H ., Ten Noever De Brauw, M. C ., and D evos, R. H ., N a tu re , 1969, 221, 1126. 2 .4 .8 Je n s e n , S ., J o h n e ls , A. G ., O lsso n , M ., and O t t e r l l n d , G ., N a tu re , 1963, 224, 247. 2 .4 .9 Z ltk o , V ., B u ll. Environ. Contam. T o x ico l. 1970, , 464. 2 .4 .1 0 V e lth , G. D ., E nv iro n . H e a lth P e rs p e c t. 1972, 1 , 50. 2 .4 .1 1 Kimbrough, R ., CRC Reviews o f T oxicology 1974, J a n . , 448, Chemical Rubber Company, C lev elan d . 2 .4 .1 2 S ta llin g s , 0. L ., and Mayer, F. L ., Environ. H ealth P e rsp e c t. 1972, b 159. 2 .4 .1 3 Hansen, D. J . , P a r r is h , P. R ., Love, J . J . , W ilson, A. J . , J r . , and W ilson, P. D ., B u ll. E nviron. Contam. T o x ico l. 1971, , i f 3. 2 .4 .1 4 Vos, J . G ., and Koeman, J . H ., T o x ic o l. Appl. P harm acol. 1970, ^Z* 636. 2 .4 .1 5 F e a k a ll, D. B ., B u ll. E n v iro n . Contam. T o x ic o l. 1971, J6, 100. 2 .4 .1 6 T reon, J . F . , C le v ela n d , F. P . , C appel, S. W., and A tc h ie y , R. W., Am. In d . Hyg. Qu. 1956, 1 7 , 204. 2 .4 .1 7 Dauppi, T. A ., and C u rrie , C. C ., P ro d u ct E n g in e e rin g , 1949, 20, 108. 2 .4 .1 8 C u rrie , C. C ., and Sm ith, B. F . , In d . Eng. Chem. 1950, _42, 2457. GENP 006128 774777 63 2 .4 .1 9 Fitzsim m ons, V. G ., P i c k e t t , 0 . L . , M i l i t z , R. 0 . , and Zisman, V. A ., T rans. A.S.H.E. (1946), 68, 365. 2 .4 .2 0 S c o tt, D. t f . , J . Am. Chem. Soc. 1946, 68, 356. 2 .4 .2 1 P atn o d e, W,, and H llc o c k , D. F . , I b i d . , 358. 2 .4 .2 2 Ford ham, S . , The S ilic o n e s . The P h ilo s o p h ic a l L ib r a r y , New York, 1961. (See a ls o i n d u s t r i a l l i t e r a t u r e su ch as B u lle tin 22-053 Dov C om ing Company, M idland, M ichigan, 1972, and 2 .4 .2 3 ASTM S tandard Method D92-4, Annual Book o f S ta n d a rd Methods P a r t 40 American S ociety of T estin g M a te ria ls , P h ila d e lp h ia , P a ., 1975. 2 .4 .2 4 1975 In s u la tln g /C irc u lts Desk Manual, 21, No. 7, 1975, Lake P u b lish in g Company, L l b e r t y v l l l e , I l l i n o i s . 2 .4 .2 5 See f o r example " D ie l e c tr ic P r o p e r tie s o f Dov C orning S ilic o n e L iq u id s " , is su e d by Dov C orning C o rp o ra tio n , M idland, M ichigan. 2 .4 .2 6 S to c k , A.., and S om leskl, C ., B er. 1916, 49, 111. 2.4..27 K ipping, F. S ., P roc. Roy. Soc. 1937, 159A, 131. 2 .4 .2 8 McGregor, R. R ., S ilic o n e s and T h e ir U ses, M cG rav-H lll Book C o ., New York,r 1954. 2 .4 .2 9 L ink, E ., ETE C o rp o ra tio n -- p e rs o n a l com m unication. 2 .4 .3 0 D u c k ett, D. A ., Paper b e fo re th e G en eral M eeting o f Che Edison E l e c t r i c Z n s tltu te , Transm ission and D is trib u tio n Committee, M inneapolis, M innesota, May 8, 1975. 2 .4 .3 1 M orrison, R. T ., and Boyd, R. N ., O rganic C h em istry , A lly n & Bacon, Nev York, 1966. G E N P 006129 774778 2 . U .32 Graham, P .R ., E nviron. H e a lth P e r s p e c t 1973* 3,* 3* 2.1*.-33 F o r s t e r , E. 0 . , p e rso n a l com m unication. 2.U-3U R utkoV ski, A. J . , and F o r s t e r , E. 0 . , p re s e n te d a t American Power S o c ie ty [IEE) W in ter Power M eeting, New Y ork, 19T5* -also P ro c . V II I n t . Conf. on E l e c t r i zal I n s u la tin g M a te r ia ls , I n s t . E le c . Eng. Tokyo, J a p a n , 197** GENF WO uv 774779 65 2.5 The Scope and Influence of Government Regulations The purpose of this section Is to identify the several government agencies which have potential regulatory power over new Insulating fluids, to describe the particular area of concern over which each exercises regulatory power, and to define what criteria and procedures are used to determine whether a new fluid falls within the purview of each particular agency or regulation. The emphasis will, therefore," be on the regulations themselves; criteria and testing procedures which support or are cited in these regulations will be briefly Identified, jn SectIon these test techniques are more thoroughly explored. 2.5*1 Environmental Regulations Environmental protection regulations are developed and enforced by the Environmental Protection Agency (EPA) and by the various state depart ments of natural resources. The state agencies generally follow the Federal regulations, and they may in fact have operational responsibility for enforcing the Federal environmental regulations. Being more closely In touch with the local Issues and being under less complex operating constraints, the states can often act more rapidly than the Federal enforcement agencies. It is important, therefore, that the state and Federal environment regulatory bodies act under rigorous, quantitatively definable criteria In establishing and enforcing their regulations. We will review the existing and pending Federal regulations, recognizing that these will also probably be reflected in any state acts. Insulating and dielectric fluids are typically very stable compounds which have low vapor pressures and which, therefore, do not represent a GENP 006131 774780 66 c\ significant air pollution problem. The primary environmental effect Is In water, and so the primary source of environmental regulation of such fluids Is: Public Law 92-500 (86 Stat. 816) "Federal Water Pollution Control Act Amendments of 1972" Three sections in this act are of particular Importance for evaluating the Impact of regulations: 1. Sec. 307a 'Toxic effluents" A proposed list and a final list of toxic substarces were published by EPA In the Federal Register on 7/6/73 (38FR18o MO~ and on 9/7/73 (38FR24342), respectively. Criteria for selecting these substances were tncluded, thereby Indicating the standards by which new substances can be evaluated. The toxic substance list Is not enfor ceable, however, until standards for allowable levels of these toxic substances are finally promulgated. Although standards were proposed oh 9/7/73 these have not yet reached final legal status. 2. Sec. 311 "Oil and Hazardous Substance Liability" (Spills, leakage, pouring hazardous substances Into navigable waters of the U.S.)i On 9/22/7*+, proposed rules were Issued: "De signation and determination of removability of hazardous sub stances from water" (39FR30466). A list of hazardous sub stances and selection criteria were Included. This never reached the final promulgation stage and is In fact now being rewritten. The existing oil spills regulation (38FR3*+16*0 may serve as a guide for the new proposal. GENP 006132 *See Section 2.5.3 "Occupational health," for air quality criteria In the working place. Federal Register (FR), vol. 38, page 81801+11, July 6, 1973. 774781 67 3. Sec. 402 "Pollution discharge permits" This section empowers the regional offices of EPA to Issue permits limiting the allowable levels of pollutants In effluent discharges. Limitations.on polychlorinated biphenyls have already been Included In several permits. "Pollutanti1Is defined (in Sec. 302) as effluents which "would Interfere with the attainment or maintenance of that water quality In a specific portion of the navigable waters which shall assure protection of public water supplies, agricultural and Industrial uses, and the protection and propagations of a balanced population of shellfish, fish and wildlife, and allow recreational activities In and on the . water,....11 In addition to the existing legislation cited above, Congress Is in the process of working on a~Tox!c Substances Control Act, which would give EPA more direct control on production and use of Identified toxic substances. 2.3.2 Poisonous Ingredients In Foods The Food and Drug Administration (FDA), an agency of the Federal Department of Health, Education and Welfare, has the responsibility for administering the consumer protection standards established by the Federal Food, Drug, and Cosmetics Act of 1338 with amendments (FFDCA) (lL S. Code, Title 21). The various state departments of public health cooperate In maintaining proper food standards, under authority of state public health legislation. Whereas FDA enforcement authority concerns only foods involved In Interstate commerce (Sec. 703 and 704 of FFDCA), the state may, of course, take local action. GENP 006133 774782 68 "Poisonous substances" Include all substances documented to be harmful to human health. Thus, they may be specifically Identified In FDA regulations' (as in the case of PCB's; see 38FR18096, July 6, 1973) or known to be poisonous from other reliable sources such as "The Toxic Substances List" published by the National Institute for Occupational Safety and Health (see Sections 2.9*3 below). Likewise, tolerance levels are not specifically Identified by FDA for each known poison, but rather this is judged on a case-by-case basis, as specified In Sec. 406 of FFDCA. Any new insulating or dielectric fluid which Is identified by any Federal agency to be poisonous would thus come within FDA jurisdiction. In relation to this, It should be noted that the FDA regulations on PCB's (38FRI8096) specifically exempts PCB transformers and capacitors; being in sealed containers was an influential factor In this decision. In enforcing Its regulations, FDA can request a manufacturer to recall an adulterated product, under threat of prosecution. .It can, under court authority, seize a shipment of adulterated food. And it can legally prosecute manufacturers of Illegally adulterated foods. Actions are reported in: "FDA Weekly report of seizures, prosecutions, injunctions, field corrections and recalls," published weekly by the FDA Press Office, Rockville, HD 20892. 2.5*3 Occupational Health The Occupational Safety and Health Administration (OSHA), a part of the Department of Labor, has the responsibility "to assure so far as possible every working man and woman in the Nation safe and healthful working conditions as stipulated In: 77478 3 69 Public Law 91-596 (84 Stat. 1590) "Occupational* Safety and Health Act of 1970" Dielectric and Insulating fluids could come within the scope of OSHA regulations In two ways: 1. During processing of the material by the capacttor and trans former manufacturers 2. By use of the capacitors and transformers In or closely adjacent to work areas. In the Act cited above, the following responsibilities are defined: 1. The Secretary of Labor (l.e., OSHA) Is to promulgate standards for toxic substances (Sec. 6). 2. The Secretary of Labor (OSHA) also Is empowered to Inspect ./orking places (Sec. 8) and to enforce the standards (Sec. 10, 17)* 3* The Secretary of Health, Education and Welfare, through its agency. The National Institute of Occupational Safety and Health (NIOSH) Is to carry out research, develop criteria, and carry on training concerning health and safety In the working place (Sec. 20, 21, 22). Thus, NIOSH has the job of establishing standards, while OSHA prom ulgates and enforces these standards. The following publications and standards have resulted regarding toxic substances: "The Toxic Substance List-- 197** Edition" NIOSH, Rockville,*MD 20852 June 197**. In this publication, a large number of toxic substances are listed, along with toxic dose levels, and the reference sources for these toxic doses. Four PCB's are included.. A new Issue of this Is now In preparation. 774784 TO "Occupational Safety and Health Standards," 39FR23502, June 27, 1974. Sec. 1916-93 (CFR Title 29 - Labor) Table G1 lists contaminants, including chlorodI phenyl (42% Cl); skin 8-hour time weighted average exposure not to exceed 1.0 mg/m^, and chtordlphenyl (54%), 8-hour time weighted average skin exposure 3 not to exceed 0.5 mg/m . The source of these standards Is 41 CFR 50-204.50 which cites: threshold Limit Values of Airborne Contaminants for 1968," Amer. Conf. of Govn. Industr. Hygienists. The National Electrical Code (NEC) - 1971 (ANSI Cl-1971) has been Incorporated within 0SHA regulations (29CFR 1910.308; see 39FR23502, June 27, 1974). Dielectric fluids for transformers and capacitors therefore Fall within 0SHA regulations Insofar as these fluids are effected by the NEC. (See Section 2.6 of this report for further discussion of the NEC.) GENP 006136 774785 71 2.5.** Transportation The Department of Transportation (DOT) Is Involved In both the use and the control of Insulating fluids In these two ways: 1. Use. High speed mass transit systems employ electric traction. The electric transformer is, therefore, a rather key item. It must be small because of the size limitations on the transit cars and fireproof In the event of an accident. Askarel transformers are, therefore, universally used in present ground electric .transit systems.* DOT may, therefore, be a significant participant in the move toward both safe and reliable techniques for continued use of PCB's and for substitutional use of new insulating fluids. There Is little documentation which has yet come to our attention on work by DOT cn improved.transformers. 2. Control. The transportation of hazardous materials falls within DOT'S regulatory power, as Identified In: *9CFR Parts 100-199 Transportation; revised as of October I, 1975. The following sections are particularly pertinent to the insulating fluids question: 1. List of Hazardous Materials; sec. 172.5 a. Hone of the PCB's, by any of their chemical or trades names, Is on the list. b. Any substance which qualifies for the list under definitions given In other sections must be treated as if on the list. The Japanese retained askarel In their electric rail cars even after their otherwise complete ban on PCB's; they apparently are now experimenting with a silicone substitute. GENP 006137 774786 72 2. Dielectric and insulating fluids would be identified as Class B poisons if they were found to be toxic. (See Sec. 173.3*3) 3- Class B poison ("less dangerous") sec. 173-3*3 1iquld~ or.solTd substance "known to be so toxic to man as to afford a hazard to health during transport, or which, in the absence of data on human toxicity...fal1 within any one of the following categories: 1) Oral Toxicity: produce death within *8 hours in half or more of a group of 10 or more white lab oratory rats weighing 200 to 300 grams at a single dose of 50 milligrams or less per kilogram of body weight when administered orally. 2) Toxicity on inhalation: those which produce death within *8 hours in half or more than half of a group of 10 or more white laboratory rats weighing 200 to 300 grams, when inhaled continuously for a period of one hour or less at a concentration of 2 milligrams or less per liter of vapor, mist, or dust, provided such concentration is likely to be encountered by man when the chemical product is used In any reason able foreseeable manner. 3) Toxicity by skin absorption: those which produce death within *8 hours in half or more than half of a group of 10 or more rabbits tested at a dosage of 200 milligrams or less per kilogram body weight, when administered by continuous contact with the bare skin for 2* hours or less. The foregoing categories shall not apply if the physical characteristics of the probable hazards ' to humans as shown by experience indicate that the substances will not cause serious sickness or death. Neither the display of danger or warning labels pertaining to use nor the toxicity tests set forth above shall prejudice or prohibit the exemption of any substances from the provisions of Parts 170-189 of this chapter. (29 FR 18753, Dec. 29, 1988, as amended by Arndt. 1.73"3, 33 FR 1*922, Oct. *, 1968; 33 FR 19823, Dec. 27, 1968.) GENP 006138 774787 73 4. Effect of ITst Proper procedures for the transport of hazard ous materials are stated in the following sections: Pt. 173 Shippers 173>34*t Packing for class B poisons, liquid a) Closing and cushioning. All containers must be tightly and securely closed. Inside containers must be cushioned as prescribed, or in any case when necessary to prevent breakage or leakage. b) Outage. Outage for containers of liquid poison for transportation by carriers by rail freight, rail express, highway, or water must be as follows: 1) Containers must not be entirely filled. Sufficient Interior space must be left vacant to prevent leakage or distortion of containers due to the expansion of the contents from increase of temp erature during transit. 2) The proper vacant space (outage) in a tank car or other shipping container depends on the co efficient of expansion of the liquid and the maximum increase of temperature to which it will be subjected in transit. Outage must be cal culated to the total capacity of the container. 3) Liquid poison must not be loaded into domes of tank cars. 4) In tank cars* outage must be calculated to percentage of the total capacity of the tank, l.e., shell and dome capacity combined. If the dome of the tank car does not provide sufficient outage, then vacant space must be left*for the shell to make up the required outage. 5) The outage for tank cars must not be less than 1 percent. 6) No cargo tank or compartment thereof used for the transportation of any liquid poison shall be com pletely filled; sufficient space shall be left vacant in every case to prevent leakage from or distortion of any such cargo tank by expansion of the contents due to rise in temperature in transit, and such free space (outage) shall be sufficient in every case so that such cargo tank shall not become entirely filled with the 1Iquld at 130F. GENP 006139 774788 TL 173-3^5 Exemptions for poisonous liquids, Class B. a) Poisonous liquids, class B, as defined In 173.3*0, except those for which no exemptions are provided as Indicated by the "No exemption" statement In 172.5 of this chapter, or as provided for in 173.359(c), in tightly closed inside containers, securely cushioned when necessary to prevent breakage and packed as follows, are exempt from specification packaging, marking, and labeling requirements, except that marking name of contents on outside container Is required for shipments via carrier by water. Shipments for transportation by highway carriers are exempt also from Part 177 of this chapter, except 177-817 and Part 397 of this title. 1) In glass or earthenware containers not over 1 quart capacity each, or In metal containers or poly ethylene bottles not over 1 gallon capacity each, packed in strong outside wooden boxes or barrels. 2) In glass or earthenware containers not over 1 pint capacity each, or In metal or polyethylene containers not over 1 quart capacity each, packed Tn strong outside flberboard boxes. 173 .414 Po sons material labels Pt. 174 174.532 174.538 174.586 Rail Freight Loading other hazardous materials Rail freight; loading and storage chart of hazardous material Handling hazardous materials, by carriers by rail freight. Pt. 175 Carriers by Rail Express Pt. 176 Rail Carriers in Baggage Service 176.702 Hazardous materials , Pt. 177 177.821 177.841 177.848 177.860 Public highway carriers Hazardous materials forbidden or limited for transportation Loading; poisons Loading and storage chart of hazardous materials Accidents or leakage; poisons Pt. 178 Shipping container specifications Pt. 179 Specifications for Tank Cars GENP 006140 774789 T5 2.6 The scope and influence of insurance and fire code requirements. In addition to the various federal and state governmental regulations which might restrict the use of fluids in electrical equipment, one must also make sure that such equipment does not conflict with insurance and fire code regulations. The two are closely related and therefore can be most easily discussed together. The National Electrical Code (NEC) is one part (volume 6, 1975) of the National Fire Codes, issued by the National Fire Protection Association (NFPA). This code is developed and continually updated by a set of committees which is sponsored by NFPA and is composed of representatives from manufacturers, users, fire insurance companies, independent testing laboratories, and municipal and state fire safety and regulatory agencies. As such, it is an authoritative work universally recognized as a standard statement of safe electrical fire practice. Although the NEC is not In Itself law, it is usually adopted with various levels of modification as the legal electrical building code. Equipment to be legally installed within the jurisdiction of such a code must therefore conform to NEC. As presently written, the NEC specifically recognizes mineral oil and askarel as insulating fluids. Since no more general descriptions or definitions are given, one is led to infer that other fluids are excluded unless specifically Identified in future editions. To get a new material listed in the NEC, the manufacturer must propose the desired inclusion to the Electrical Coordinating Committee of NEC, along with evidence substantiating the fire safety of the material. Before approval, however, the.committee would probably require testing and safety verification by an independent laboratory such as Underwriters Laboratory (UL) or Factory Mutual Engineering and Research (FMER). GE^P 006141 774790 76 UL Is an independent not-for-profit testing laboratory which carries out tests on products for manufacturers and makes "listing" or "classification" judgement based on these tests: "listing" The product is deemed to meet the requirements of the NEC. "classification" A material will be given a flammability class ification, based on a scale between 0 (water) and 100 (diethyl ether) ;* the procedure is outlined in: "Tests for comparative flammability of liquids," UL Standard No. 3^0. Whereas NEC is an installation guide, local ordinances will often look to the UL listing to verify.that the product meets NEC standards and therefore can be installed as directed by the code. FMER is a service arm of the factory Mutual System of insurance companies. It carries out testing of equipment and issues "approvals'1' or "acceptances" based on these tests: "approval" The product is deemed to be safe and suitable for general applications. "acceptance"* A particular installation of equipment and materials meets fire safety standards. Such a safety test could be initiated upon request by a manufacturer or by one of the FR insurance companies. An Installation of electrical equipment must not only meet fire ordinances but also must be covered by fire insurance. The Insurance rates are generally set by the State Insurance Commission, but an insurance company must have veri fication of the safety of the installation before agreeing to write insurance coverage. The insurance Inspector will therefore generally look to UL or FH ENP 006142 774791 77 acceptance, or to some other indication that the installation meets NEC requirements. The inspector might also base his decisions on his company's rating of the requesting company and possibly on the users or manufacturer's own tests. An experimental unit with a new insulating fluid might for instance be accepted for further field testing under this latter situation. If one unit within a larger installation does not meet standards, temporary approval may be granted with the understanding that the substandard unit be upgraded to an accept able level within a specified period.' It should be noted that utilities are often self insured and are granted exclusion from the local codes based on NEC. It is the general practice of utilities tc comply with NEC, however, and they often work closely with local fire protection people to make electrical installations safe. When utility owned equipment is installed in users buildings, often tiie local code or insurance requirements would necessitate that NEC practice be ro 'lowed. / A further note on the NEC Is that it has been adopted in toto by OSHA ("Occupational Safety and Health Standards," 2SCFR 1910.308 - See 3SFR23502, June 27, 197M and it therefore has a very broad legal importance in industrial facilities. OSHA regulations are discussed more extensively in Section 2.5.3. tM900 dMHO 774792 78