Document X75Z6vpB19rm5pwGwJjD6NdqJ

sill. JUN 1 |9?6 BULLETIN NO. IC/FF-ttW (RviMd March, 1975) TRANSFORMER Inspection & Maintenance Guide Monsanto j TOWOLDMON0038371 WATER_PCB-00022840 SECTION A TRANSFORMER ASKARELS...........................................1 I. Introduction ...........................................................l II. History of Trade Name Types..............................1 Table I - The Composition of Transformer Askarels .......................................... 2 III. Interchangeability ................................................2 IV. Table II --Official Transformer Askarel Shipping Specifications........................................3 V. Ordering Instructions .......................................... 2 VI. Stability..................................................................2 VII. Precautions When Handling Drums, Tank Cars and When Opening Transformers........................ 2 A. Keep Dry During Handling ...........................2 Table III - Handling and Pumping Temperatures.................................. 4 B. Use Ordinary Personal Precautions ..............4 C. Precautions on Opening an Askarel Transformer........................................5 VIII. Avoid Environmental Pollution...........................5 1. Labeling Askarel Transformers............. . 6 2. Disposal of Liquid and Solid Wastes ........... 6 3. Conditioning of New or Recycled Askarel .6 4. Teardown of Transformers for Repair or Scrap ........................................7 5. Transformer Disposal..................................... 7 IX. Expected Service Life.......................................... 7 X. General Characteristics of Transformer Askarel Fluid.......................................................... 7 XI. Sampling Transformer Aritarel Fluid ................ 8 XII. Evaluation of Askarel Received in New Equipment ............................................... 8 XIII. Dielectric Breakdown Voltage -- Moisture Relationship.......................................... 9 Table IV - Relation of Dielectric Breakdown Voltage to Amount of Dissolved Water in Askarel and Mineral Oil........................................9 Table V - Approximate Solubility of Water in Transformer Askarel and Mineral Oil .... 10 XIV. Turbidity ............................................................. 10 XV. Check Points for Maintaining Askarel Insulation ..............................................10 A. General Considerations.................................10 B. Modern Sealing Procedures .........................11 C. The Older Sealing Arrangements................. 12 XVI. Periodic Fluid Inspection and What Checkpoints Mean ................................... 12 A. Visual Inspection........................................... 13 8. Dielectric Breakdown Voltage ....................13 XVII. Inspection Checklist ...........................................13 XVIII. Contamination in Transformers.......................... 14 Table VI - Effect of Common Insulation Materials on Power Factor and Dielectric Strength..............................................14 Table VII - Effect of Common Insulation Materials on Volume Resistivity of Askarel............................................................. 14 XIX. ASTM Method for Investigating the Compatibility of Transformer Insulation and Construction Materials in Askarels............15 XX. Refining Askarel for Re-Use..............................15 A. F iltering Through Dry Blotter Paper to Remove Moisture and Extraneous Particles......................................15 XXI. XXU. TaOle VIII - Water Removal by Filtering Askarel Through a Paper Press ......................... 16 B. Disposal of Solid Wastes ..............................16 C. Solid insulation Requiring Drying . . . 16 D. Earth Treatment for Maximum Improvement of Power Factor and Volume Resistivity ................................... 16 Table IX - Effect of Power Factor and Volume Resistivity ......................... 17 Cleaning Arced Transformers...................... 17 Sampling Askarel ..................................... 17 SECTION B ASKAREL FILLED SWITCHES AND TERMINAL CHAMBERS ......................................19 I. Introduction................................................. 19 II. Sources of Contamination..................... 19 III. Sealing Switches and Terminal Chambers 20 IV. Askarel Used Under Mild Arcing Conditions 20 V. Maintenance for Askarel F illed Switches 20 VI. Askarel Under Excessive Temperature or Fault Conditions ...........................................21 SECTION C TOXICITY AND SAFE HANDLING.............................. 21 I. Inhalation.................................................. 21 II. Skin Contact........................................................ 21 SECTION D ANALYTICAL SERVICES ON TRANSFORMER ASKAREL AVAILABLE FROM MONSANTO . Types of Analyses Available: .......... 1} Routine Maintenance Check . . . 2) Complete Analysis..................... 31 Analysis After Earth Refinement 22 22 22 22 22 SECTION E APPENDICES..................................................................... 23 Appendix A - Askarel Stability and Composition of Arc Formed Gas...................................23 Appendix 6 - Solubility of Gas in Transformer Askarels .....................................................23 Appendix C - Effect of Temperature on Dielectric Breakdown Voltage of Askarel................... 23 Appendix D - Comparison of the Approximate Viscosity in Saybolt Universal Seconds of Transformer Askarels and Mineral Oil........................... 24 Appendix E - The Density of Inerteen 54201 KA 7336-9 and Transformer Pyranol A13B3B-3.......................................................... 24 Appendix F - Thermal Conductivity Values of Transformer Pyranol A1 3B3B-3................................ 24 Appendix G - Heat Capacity .......................................... 24 Appendix H - Coefficient of Expansion........................ 24 Appendix I - Fire Resistance.......................................... 24 Appendix J - Seals, Properties and Procurement .............................................................25 Appendix K - Caution Label .................. 25 NOTICE "Nothing contained herein is to be construed as a recommendation to use any product n conflict with any patent. MONSANTO MAKES NO WARRANTIES AS TO THE FITNESS FOR A PARTICULAR PURPOSE OR MERCHANTABILITY OF ANY PRODUCT REFERRED TO, no guarantee of satisfactory results from reliance up on contained information or recommendations, and cm claims all liability for any resulting loss or damage.'' | , I | | ; 0614191 TOWOLDMON0038372 WATER_PCB-00022841 Transformer Askarel I. Introduction The term "askarel" as defined by IEEE, ASTM and the National Electrical Code generally describes a broad class of fire-resistant* synthetic chlorinated hydrocarbon insulating liquids widely used m transformers, reactors and accessory equipment operated at power frequencies. Askarels of various compositional types are in use (For the general properties and types see ASTM D-2283.) Under arcing conditions the gases produced, while consisting of predominantly non-combustible hydrogen chloride, can contain varying amounts of combustible gases depending upon the askarel type. This manual describes the operating characteristics of transformer askarel liquid insulation as manufactured by Monsanto and how it differs from mineral oil. Appropriate handling and disposal procedures for both scrap askarel liquid and impregnated solid materials are given in accordance with the guidelines recommended by the American National Standards Institute. The information is based on facts gathered by Monsanto over 40 years as a producer of askarel, plus knowledge gained from the experience of transformer manufacturers and users. This guide outlines the maintenance required for askarel fluid in "modern" transformers ana offers suggestions for sealing and maintaining askarel in old units. By following this guide, we believe users will obtain maximum service from askarel insulation with a reasonable minimum of maintenance If questions arise relating to the designing and building of transformers, these should be referred to regular transformer suppliers. Monsanto gratefully acknowledges the assistance, guidance ana tne contributions of certain data by the following; Edward L Raab - General Electric Dr. T. K, Sloat -- Westinghouse Electric II. History of Trade Name Types "Askarel" is the generic name tor the fire-resistant liquid msuiat on and coolant first used by General Electric Company in 1932 for their Pyranol1 brand name fire-resistant transformers, Westinghouse Electric Corporation uses their brand name, Inerteen.2 Whatever the trademarked brand, the askarel contains cnonnatea biphenyl - one of the best liquid insulations developed by science. This inert material is chemically stable, fire-resistant, heat such.non-corrosive, and has high dielectric strength under the operating conditions encountered In transformers. In addition to manufacturing Aroclor (chlorinated biphenyi Monsanto also mixes this dielectric fluid with chlorobenzenes ip produce the presently used Inerteen and Pyranol blends descnuea n Table I. "NOTE. Materials designated 'fire resistant' generally are more J s ignue, or once ignited, burn at a slower rate than corresponding convent ..-.j materials. This term does not mean that fire rasittam materials wm not ovn However, whan properly used, Monsento'i fire resistant ASKAREL FluiDS d>e useful <n helping customers meet their fire safety requirements." ^Trademark of General Electric Company trademark of Westinghouse Electric Corporation Registered trademark of Monunto Company o&myz ^ | TOWOLDMON0038373 WATER_PCB-00022842 Table I Tha Competition of Typical Transformer Aikareli Method ASTM 02283 Type D Type E Type G Trade Names Inerteen 70-30 Inerteen 100-42 Pyranol A13B3B3 Ingredient! (% by wt.) Aroclor 1254, chlorinated biphenyl (64% chlorine by weight) Aroclor 1242, chlorinated biphenyl (42% chlorine by weight) 70 Trichlorobentene 30 Phenoxypropene oxide icavenger Oiepoxide icavenger 0.1B to 0.22 100 0.18 to 0.22 60 40 0.115 to 0.135 ASTM Method D-2283, titled "Chlorinated Aromatic Hydrocarbons (Askire/s) For Transformers", alto lifts the composition of all transformer atkarels used at various times since 1932. Monsanto manufactures similar transformer askarel fluids in England where the trade name Pyroclor is used. - III. interchangeability In general all transformer askarels are interchangeable. However, it is suggested that the transformer manufacturer be consulted prior to mixing in significant proportions or total substitution. IV. Transformer Askarel Specifications Specifications for the three modern transformer askarel fluids are shown in Table II. ' V. Ordering instructions Monsanto's current policy is to sell askerel transformer fluids only to transformer manufacturers. Others interested in these fluids should contact the manufacturers of askerel transformers and not Monsanto. The transformer name plate indicates the transformer maker and usually gives sufficient data to identify the specific askarel fluids used. VI. Contamination Askarel insulation must never be mixed with mineral oil. Over two percent of mineral oil by volume in askarel begins to lower its fire resistance. In modern transformers, the principal "enemy'' of askarel is contamination by water. Keeping askarel water-free will insure long-time service. Askarel is heavier than water. If water gets into askarel insulation, only a tiny amount (approximately 125 ppm) dissolves - the rest floats on top. Askarel is very insoluble in water, only about 200 parts per billion of askarel dissolve in water, at normal temperatures. VII. Precautions When Handling Drums, Tank Cars, and When Opening Transformers The following ere significant precautions: A, Keep Dry During Handling: In handling, storing, sampling and inspecting askarel - and in 06U193 TOWOLDMON0038374 WATER_PCB-00022843 Specification Properties1 Color, APHA Condition Water content, ppm (ASTM D1533-60) Acidity. mg KOH/g (ASTM 0974 55) Dielectric Strength, 25*C, 0.1 in. gap (ASTM 0877 49) Dielectric Constant, I00"C, 60 Hz (ASTM D924-49) Volume Resistivity, 100"C, ` , 500 volts DC 0.1 inch gap, 10s ohm-cm : (ASTM D1169) Inorganic chlorides, ppm (ASTM D1821 and G.E. Method E4C418) Refractive index, 25C (ASTM D1807I Viscosity at 37 8C (ASTM 088-56) Saybolt Universal Seconds Pour Po.nt C (ASTM D 97 57) Specific gravity 25/15.5*0 (ASTM D1810) Burn point (ASTM 092) Distillation range (ASTM D20 56) corrected for stem and barometric pressure Table Transformer Asfcard Specifications (New Fluid) General Electric Co. Transformer Pyranol A13B3B-3 ASTM D2283 Type G 150 max. Clear 30 max. 0.014 max 35 KV, min. 4.2 to 4.6 Westinghouse Transformer Inerteen 70-30* ASTM D2283 Type D 150 max. Clear 30 max. 0.014 max. 35 KV, min. 4.2 to 4.5 100 0.10 max. 1.6110 to 1.6120 44 to 48 38 or lower 1.495 to 1.510 None to boiling 1st drop 200C min. 40% max. below 270*0 90% 379 to 394 100 0.10 max. 1.6153 to 1.6173 56 to 61 30 or lower 1.518 to 1.528 None to boiling 1st drop 200C mm. 35% below 270C 90% 379 to 394 Weetinghouse Transformer Inerteen 100-42* ASTM D2283 Type E 60 max. Clear 35 max. 0.01 max. 35 KV. min 4 7 to 4 9 100 0.05 max. 1.6240 to 16260 82 to 92 -17 or lower 1.381 to 1.392 None to boiling 10% 325*C min. 90% 360 max. F ixed chlor me 56 4 4 o 5% 55.6% mm 43 + 0 5% Corrosion lest Color. APHA Acidity, mg KOH/g Inorganic chlorides ppm Condition Scavenger content Typical Properties^ After heatmq with aluminum for 6 hrs. at 200 to 220C, the aluminum must not be corroded on either visual or weight inspection and the askarel should meet the following specifications: 200 max 200 max. 200 max. 0.014 max. 0.014 max 0 01 max 0.15 max. Clear 2.0 max. Clear 0 15 max. Clear 0.115 to 0 135% 0 18 to 0.22% 0 18 to 0.22% Diepoxide phtnoxypropene oxide phenoxypropene oxide Coefficient of Thermal Expansion 0 0007 0.0007 0 00068 (ASTM D 190Ji. cm7/cm?/C Arc formed gusi's 'WeMniyhi'UM .< : li'tn Diivoit' nuiiitm it.eneen i4?01K 1.. i;.priwr 70 30 iirirt the i pnvate numb*. ` >4 .`01 CM Iq. Lie.leer. 100 42 Askd'els ol various compos.l>onal types an; gs?<1 Under arcing condiiions the gases produced, while consisting piedonMnjnily ol non combustible hydrogen chlonde can include varying amounts of combustible gases depending upon ihe askarel type Insulation systems m< o< porafrxj these askarels <md cellulos* or other organic materials may wit diced pr<xlu<f gasi-ons mixtures wh'lh jie moderately flammable As a precauiion. such gases should be irc:i.jvi'j tiom in.- jskji. i bv bubbling u>y .. .. itii uugl> tin <n. i jiJ flushing tfie ! u<'' ailh dr y n.ti o.j, i. Q * Theit- ...j,'! > I .r.a I lei spt-t it., jiinni only IO I Ilf- ten; that they com. i0e wit*' Monsanto's publ- shed '.pecificalrOm 06U19<t idles i iiiloiAskaieiri'.'i TOWOLDMON0038375 WATER_PCB-00022844 operating askarel transformers - take every precaution to guard the askarel insulation from exposure to high humidity and moisture contamination. Keep 5 or 55 gallon drums of askarel dry; lay stored drums on their tides with the bung at the highest point from floor to keep water off the drum head (which can be sucked into the askarel by the drum "breathing"). This precaution is not necessary when drums are stored incoors, which is the preferred place for storage. To avoid leakage the drums used for askarel are of heavy construction. Sixteen gauge metal is used, with special rim seal and bung construction. The drums, should be drained as completely as possible and then flushed twice with kerosene type solvent to remove all of the askarel. Accumulated liquids and washings should be collected and should be incinerated at high temperatures, e.g., about 200Q*F, to destroy the polychlorinated biphenyls (PCBs). See Section A, VIII. Tank cars used to transport askarels are in exclusive service and not used interchangeably for other products. All cars must be unloaded through the top (dome fitting) either by pumping or with controlled pressure using dry air or dry nitrogen. If nitrogen has been used for unloading it is necessary to advise the shipper so that when the car returns the nitrogen can be replaced with dry air before any one may enter the car, If the car is to be unloadea by pumping it will be necessary to use a dryer on the air intake line to remove moisture. All tank cars are fitted with steam coils, which are available for unloading under extreme low temperature conditions. ' Convenient handling and pumping temperatures are given m Table III. 6. Use Ordinary Personal Precautions: Transformer askarel has bean made, handled, and used for over 40 years. It can be handled safely with recommended orecautions. If accidentally spilled on hands, no serious skin irritation will occur. However, liquid askarel has a solvent action (similar to paint Table III Handling and Pumping Temperatures Product Unloading, Handling and Pumping Temperature C Pyranol A13B38-3 Inerteen 70-30 Inerteen 100-42 20- 56 20 55 35 - 75 thinner) on the fats and oils of the skin and prolonged contact may lead to drying and chapping of the skin. In case of contact, wash the skin with soap and water; remove and dry clean saturated clothing. Clean up spills with rags, sawdust and absorbent clay. Eye contact may result in painful irritation but no permanent damage to tissues. If askarel gets in the eyes, flush with large amounts of water. As with all eye first aid, refer to a physician, To relieve irritation, physicians have used an opthalmic anesthetic solution as well as opthalmic cortisone acetate solution, or castor oil. infrequent exposure to askarel vapors will not cause ill effects. However, prolonged exposure to high vapor concentrations should be avoided. If hot askarel must be handled in a closed or confined area, provide the area with mechanical exhaust ventilation - or 41 r\ r\ 06195 TOWOLDMON0038376 WATER_PCB-00022845 wear an organic cartridge respirator approved by the U.S. Bureau of Mines. C. Precautions On Opening an Askarel Transformer: Askarels of various compositional types are used. Under arcing conditions the gases produced, while consisting of predominantly non-combustible hydrogen chloride, can yield varying amounts of combustible gases depending upon the askarel type. Insulation systems incorporating these askarels anp cellulose or Other organic materials may, when arced, produce gaseous mixtures which are moderately flammable. As a precaution, such gases should be removed from the askarel by bubbling dry nitrogen through the askarel and flushing the gas soace with dry nitrogen before any work is performed on the apparatus. The American Institute of Electrical and Electronic Engineers Guide No. 76, March, 1974 gives more detailed instructions and guidance "For Acceptance and Maintenance of Transformer Askarel In Equip ment". This guide is published by the Institute of Electrical & Elec tronics Engineers, Inc., 345 East 47th Street, New York. New York 10017. We recommend that users of askarel transformers refer to this IEEE document. VIII. Avoid Environmental Pollution Transformer askarels contain polychlorinated biphenyls (PCBsi which have been used in the United States and elsewhere over the oast 40 years for many industrial and consumer applications. Dur ng pe past several years evidence has accumulated to indicate that RGBs are widely dispersed throughout the environment and that they can have adverse ecological and toxicological effects, The United States Government's Interdepartmental Task ^orce on PCBs, Com-72-104 19, in their March 20, 1972 report t tied, '`Polychlorinated 8ipheny/s and the Environment", recommended restricting PCBs to use in capacitors and transformers. This report is distributed by the National Technical information Service, U.S. Department of Commerce, Springfield, Virginia 22151. A document titled, "Guidelines for Handling and Disposal of Capacitor and Transformer Grade Askarels, Containing Polychlorinated Biphenyls", has been prepared and is available from the American National Standards Institute, Committee C107, 1430 8roadwav, New York, New York 10018. The scope, objectives and the composition of this committee are ANSI Committee C107 Scope: Procedures and guides,for safe use, maintenance and disposal of askarel and askarel-soaked materials used in electrical equipment. Objectives: 1. Source of technical information and advice for Feceni. State, local authorities and all others concerned. 2. Encourage development of suitable disposal tacii-t^s rd keep all concerned informed. 3. Serve as the advisory group for United States partiopat international organizat'onj: CEE, lEC, CIGR6. n Composition: Organizations active in or represented by this ANSI comm.t-ea include: National Electrical Manufacturers Association, Eect'c-c Industries Association, Institute of Electrical and Electric Engineers, American Society for Testing and Materials. E..... c Light and Power Association; Certified Ballast Manufactures Association; Environmental Protection Agency, Office of Environmental Affairs; General Services Administration, National 06UISO c-JJ | TOWOLDMON0038377 WATER_PCB-00022846 Bureau of Standards; Department of the Army; Rural Electrification Administration; Division of Environmental Research, TVA; American Public Power Association, Water Pollution Control Federation; Food end Drug Administration; National Fire Protection Association; Underwriters Laboratories; end several sections of the U.S. Depertmentof Interior. The following are oertinent excerpts taken from the ANSI Guidelines for askerel transformers: 1. LABELING ASKAREL TRANSFORMERS <Pg. 16) 4.2.2.1 New Transformers. AH new transformers that contain PCBs shall have a label of adequate durability. permanent// and prominently attached to the tank by the manufacturer, given adequate warning and instructions. A suggested label includes the following: CAUTION: The insulating liquid in this transformer contains polychlorinated biphenyls (PCBsh Care should be taken to prevent entry into the environment, in case of malfunction or leaks, consult the instruction manual or the manufacturer. 4.2.22 In-Service Transformers. The transformer manu facturer should make available suitable labels with a similar warning as shown in 4.2.2.1 tor use on existing transformers. 2. DISPOSAL OF LIQUID AND SOLID WASTES (Pg. 15) 4.1.6.5.1 General. Disposal of askarels and askarel-soaked materials should be accomplished by means in which there is no significant release of eskaral to the environment. At present, disposal is accomplished by carefully controlled incineration of liquids and soaked software, and by con trolled landfill burial of apparatus and other hardware from which askarel has bean previously drained and washed. Present knowledge indicates that proper incineration must involve a suitable balance between dwell time and temperature in the incineration plus oxygen availability and, finally, suitable scrubbers to remove the HCI that will be formed; for example, 2-second dwell time at 2000F and excess oxygen in stack gas, or f.5-second dwell time at 270CPF and 2% oxygen in stack gas. These facilities should meet the applicable requirements of the state in which they are located and should control effluents within the limits set forth in this standard. Controlled landfill or deep-well disposal can be used where permitted by federal, state, and local regulations. The ANSI Guide lists the locations of facilities that conform with the above requirements. Monsanto has such an incin erator at the W. G. Krummrich Plant, Department 831, Sauget, Illinois 62201, where arrangements can be made for scrap askarel liquid disposal for a modest fee. For disposal of solid scrap a controlled dry land-fill can be used where permitted by Federal, State and local regulations. 3. CONDITIONING OF NEW OR RECYCLED ASKAREL (Pg. 16) 4.2.1.3.1. Askarel Conditioning Equipment. The condi tioning unit should be located either in the storage tank area or in the main transformer manufacturing area for filling with askaref 4.2.1.3.2 Fuller's Earth. Conditioning of new askarel or recycled askarel requires fuller's earth treatment. The spent fuller's earth in cartridges or bags, v/ten replaced, should be allowed to drain thoroughly over drip pans to remove as much liquid askarel as possible. The cartridge units of steel mesh construction should be placed in the "STEEL CON TAMINATED WITH ASKAREL" container for disposition. Cloth bags tilled with fuller's earth should be placed in the "SCRAP BURNABLE ASKAREL WASTE" container for disposition. 06UL9! TOWOLDMON0038378 WATER_PCB-00022847 4. TEARDOWN OF TRANSFORMERS FOR REPAIR OR SCRAP (Pg. 16) 4.2.14.} Drain all askarel from (ha unit either into a holding tank or reuse or into the drum labeled "SCRAP ASKAREL" for disposition, end then allow sufficient time for all of the askarel to drain from the core and coils. 4.2.1.4.2 Remove the core and coil assembly from the transformer. Sufficient absorbent material should be placed on the floor to absorb any askarel fluid that still drips from the transformer. 4.2.1.4.3 Place all materials in the appropriate salvage containers during the dismantling for later disposition. 4.2.1.4.4 AH used materials, including rags, sawdust, tape, etc, regardless of Quantity, shall be put into the . ' appropriate containers for disposition. 5. TRANSFORMER DISPOSAL {Pg. 17) 4.2.3.6 The ultimate disposal of an askarel-filled trans former may be accomplished in either of two ways: (II Complete drainage and dismantling with the proper disposal of the askarel and askarel-soaked components as described in 4.1.5. (21 Disposition of askarel transformers by means of /unk or scrap dealers. This should be avoided unless a transformer is first drained, followed by soaking the interior with a suitable solvent. Accumulated liquids and washings are to be disposed of as described in 4.1.6. IX. Expected Service Life Manufacturers indicate that properly designed and installed askarel transformers are expected to give trouble-free service for at least 30 years. Smce their introduction in 1932, the manufacturers reooa finding the overall failure rate to be less than 0.5% for all units under test and service conditions. The Edison Electric Institute's report (1956-1958) on their member utilities publishes the failure rate foaskarel transformers as 0.13 per hundred banks per year. Mr. Frank M. Clark, who invented transformer eskarels et the Genera Electric Company in the early 1930s, made the highly pertmen comment based on his many years of experience with G.E. Pyranc (askarel type) transformers that -- "The important thing is to keep them dry - otherwise leave ther alone". These words of wisdom became especially applicable in more recen years when welding shut rather than gasketing became the mam metho'1 of sealing askarel transformers. These units are sold with th, understanding that the liquid is in a normally hermetically c'cse: system. X. General Characteristics of Transformer Askarel Fluid Appreciation of the following characteristic*, as given in the I E EGuide, leads to understanding the reasons for selecting dieiectr-c breakdown voltage and moisture as the prime practical tests to |udgthe Quality of transformer askarel fluid. Also, due to the characteristics the power factor of transformer askarel will be norma11 much higher than the corresponding values for mineral Oil. In comparison to mineral insulating oil, askarel is a relatively po'a material, i.e., its molecules are dipoles, free to rotate around their ax.' and responsive to orientation by electrical forces. Askarel aisoexhib'i a much higher dielectric constant and capacitance than insulating o>i and these differences must be kept in mind when interpreting eiectf'C. test data. Because it is relatively polar, and possesses high solvency power, aska" is much more electrically sensitive than mineral oil to traces u extraneous soluble polar materials, and consequently the choice o> 061419b | TOWOLDMON0038379 WATER_PCB-00022848 constructional materials destined for use in askarel is very critical. This sensitivity is reflected in the power factor and resistrvrty (specific resistance) of the askarel, It is important to note that, with the exception of water, the dielectric breakdown voltage of askarel is not generally adversely affected by many of the soluble polar materials to which its power factor and resistivity (specific resistance) are so sensitive, In fact, the dielectric breakdown voltage of askarel is somewhat greater than that of insulating oil. Therefore, the values assigned these dielectric fluids in newly supplied transformers are 30 KV min, and 26 KV min,, respectively. As with insulating oil, askarel must be kept dry. It can pick up moisture from exposure to humid atmosphere. Under similar conditions of exposure, askarel can pick up nearly twice as much moisture when measured on a parts per million weight basis. XI. Sampling Transformer Askarel Fluid The following precautions about sampling are quoted from the IEEE Guide. "Representative samples, whether of the complete contents or only parts thereof, are extremely important from the standpoint of valuation of the quality of the product sampled. Obviously careless sampling procedure or contamination in the sampling equipment will result in a sample that is not truly representative, This generally leads to erroneous conclusions concerning quality and incurs loss of time, effort, and expense involved in securing, transporting, and testing the sample. It is strongly recommended that all of the procedures and precautions outlined in the latest revision of ASTM D 923 (Sampling Electrical Insulating Liquids) be followed. "Because of the high specific gravity (relative density) of askarel (greater than 1), water and some other impurities are most likely to be found at or near the surface. The top sample, therefore, is considered to represent the worst condition." XII. Evaluation of Askarel Received in New Equipment Some users o< askarel equipment find it desirable to make "as received tests" on all equipment. It is quite common to use the dielectric breakdown voltage test and visual appearance as the most significant tests. If suitable equipment and trained personnel are available additional information may be obtained from the power factor, color, and moisture content tests. In sampling askarel contained in apparatus extreme care must be exercised m order to obtain a representative sample. ASTM Method D 923 should be followed. New equipment with askarel exhibiting the following characteristics is considered acceptable: Dielectric Breakdown Voltage Color Condition - Visual Water Content Power Factor at 26* C ASTM Methods 30 KV mm. 300 max. (Straw color) Clear 35 ppm max. * . D 877 D 2129 D 1702 D 1533 0 924,D 150 *The power factor of askarel taken from new transformers, reactors and accessory equipment can reflect the presence of moisture, dissolved polar compounds, or other contaminants and may vary with the type of equipment from which the sample was taken due to the different ratios of liquid*to*solid insulation and to the high solvency power of the askarel. Given an acceptable water content and dielectric breakdown voltage of the askarel as indicated above, a high power factor seldom impairs the serviceability of the askarel within rather broad limits and is (fi) 0614199 J TOWOLDMON0038380 WATER_PCB-00022849 indicative of the degree of extraneous soluble polar material* present Recognizing the possibility of a wide range of power factors being recorded for askarel in new equipment, it is difficult to establish a single limit which would be acceptable to both suopliers and users for all applications. However, as a broad guide, power factors up to about 10% at 25'Cand 60 cycles per second (hertz) do not in general indicate any abnormal contamination providing that the other criteria (water content, dielectric breakdown voltage, etc.) are met. Much higher power factors may indicate excessive contamination or the misapplication of the solid materials used m manufacture in contact with the askarel and should be investigated. r XIII. Dielectric Breakdown Voltage -- Moisture Relationship The dielectric breakdown voltage of askarel is highly sensitive to excess moisture; not sensitive to ordinary dissolved polar materials. While the dielectric breakdown voltage can also be lowered by severe arcing, askarel turns noticeably black or has particles of sooty carbon floating m it if arcmg has occurred. Then the transformer should be repaired and the askarel replaced. If the dielectric breakdown voltage is checked periodically and decreases significantly - this indicates moisture pick up, arcmg, or both. When the dielectric breakdown voltage has dropped to 26 KV or less, an analysis for water is necessary, If water is found m excess o* 40 ppm at room temperature, its source should be located and corrections made. When the moisture content-approaches 125 ppm (saturation level at room temperature), the dielectric breakdown voltage of askarel drops below the value required for efficient insulating. The moisture content should not be allowed to rise over 70 ppm, sampled at ooerating temperature. If the moisture content is found to be m a satisfactory range and the dielectric breakdown voltage is low. the transformer manufacturer should be consulted, I Table IV shows the relationship of dielectric breakdown voltage vs. moisture and Table V indicates the approximate water solubility limits m askarel and mineral oil. . Table IV Relation of Dielectric Breakdown Voltage to Amount of Dissolved Water in Askarel and Mineral Oil Water Content (PPM) Breakdown Voltage (ASTM 0077) Askarel Mineral Oil 0 70 KV 50 KV 20 55 39 40 47 30 60 40 26 30 38 22 no 10 5 OolVOO TOWOLDMON0038381 WATER_PCB-00022850 Tabl V Approximate Solubility of Water in Tranaformer Askarel and Mineral Oil !L 30 22 20 4 10 14 0 32 10 50 20 68 30 86 40 104 Amount of Water (PPM) Dissolved Askarel Mineral 88 16 10 28 13 41 20 65 33 94 58 128 85 170 130 XIV. Turbidity .., may be the visual sign of undissolved water, or may indicate dir:. Cloudiness may also result from cold precipitation of tin tetraphenyl "scavenger" that was used in the earlier Pyranol transformers. This scavenger begins to come out of solution around 15*F above zero. To redissolve it requires heating to 15Q-200*F and agitation. High dielectric breakdown voltage will quickly indicate that any turbidity present is not moisture; that the insulating efficiency of the askarel is still excellent. However, if the dielectric strength is below 26 KV, moisture should be determined, using the Karl Fischer method (ASTM D1633-60). The dielectric breakdown voltage rest for askarel serves primarily as an indicator for moisture, it is by far the most important maintenance test lor transformer askarel. XV. Check Points for Maintaining Askarel Insulation A. ' General Considerations: Modern eskarel transformers with welded construction or silicone or Viton* gaskets (hand hole-cover, switch and terminal compartment covers) and with properly constructed bushings require little maintenance. Witn properly constructed trans formers, annual or semi-annual visual inspection and dielectric breakdown voltage test of the askarel fluid should suffice for routine maintenance checking over many years of service. However, many askarel units were installed in the early 1930s before the development of some of the better modern gasketing materials and before improved designs were developed for sealing out moisture. Such early units should be, and can be, modernized. Leaky or deteriorated gaskets should be replaced. If the askarel has become contaminated, it should be reconditioned. At the same time, a general clean-up of the unit end possible refimshmg may be desirable If it is not convenient to take an old transformer out of service for general repairs, leaky gaskets can be sealed temporarily by painting over the leaky area with epoxy cement. A survey of users indicates a good number of early-built askarel transformers lover 20 years old) are kept in continuous servce in critical installations by the following steps {instead of modernization). The operating units are equipped with compound pressure gauges for reading pressure above and below atmospheric. Positive 'Trademerk of E. I DuPont DeNemoun & Company, Inc. 06l4d01 TOWOLDMON0038382 WATEFLPCB-00022851 pressure is maintained on the shell by introducing nitrogen at 2 to 3 pounds above atmospheric. Regular workmen in the area daily record the temperature and pressure. If a sudden pressure drop is noted more nitrogen is introduced and the gaskets are checked for leaks with soap solution. Leaks are sealed by applying epoxy cement. 8. Modern Sealing Procedures: Transformer purchasers should specify the following moCern techniques for sealing: 1. Welding Construction; Covers, radiator connections, switch and terminal housings, instrument connections, etc, should be welded. 2. Bushing Connections: A number of bushings heve been developed to obtain a proper seal for the electrical connection through the tank wall. They are classified as follows: 1) Welded Type (Bushing flange welded to tank wall) a. Cast resin bushing with a molded seal to the bushing stud and external stainless steel or copper flanges. b. Rolled flange bushing with the metal to porcelain seal at the cap and flange made by being rolled into grooves in the porcelain over silicone rubber rings The seal between the cap and stud is made by welding. c. Porcelain or glass bushings with metal to glass or metal to porcelain seals. 2) Bolted Type (Bolted to tank wall) a. Cast resin bushings with either cast or metal flanges containing recessed gasket grooves. b. Porcelain or glass bushings with flanges containing recessed grooves or gasket stop. The gaskets may be either of rectangular or circular crosS'Section. usually V* inch thick, Bushings with recessed grooves are suitable to use with cork, cork-nitrile rubber combinations or nitrile rubber as well as gasket materials such as silicone or Viton. 3. Smalt Size Connections: When not possible to weld, small size connection seals should be made with FlexitaHic* stainless steel rings. The surfaces must be machined and parallel. The filler between the steel laminations o* the Flexitallic ring should be either silicone or Viton. 4. Gaskets for Hand-Hole Covers; Modern design specified silicone gaskets. Such gaskets must be retained in a groove The groove preferably is machined into the flange or cover However, it can also be formed bv welding concentric steel strips to the flange or the cover. Generally the gaskets should be 5/16 to 1/2 in. thick for covers, depending on the depth of the groove or stop. A rectangular cross-section is usuaiu used. The silicone material should be Dow Corning No. 5C Silastic** or equivalent. This is e low compression sei material. For best sealing 20-25% compression 15 recommended, with ample clearance in the groove or stop to allow for this compression. No cement is required. With reasonable care the gasket is removable without damage and 1$ reuseable. Silastic 50 is slightly swelled by askarel which contributes tc the tightness of the seal. It is not deteriorated by askarel fluin or vapors. It resists weathering and it is thermally stable anc 'Trademark ot Flexitallic Gasket Company "Trademark of Dow Corning 061V202 1 <LL TOWOLDMON0038383 WATER_PCB-00022852 flexible at ail operating temperatures. It is an excellent moisture barrier. NOTE: Dow Corning, Midland, Michigan will supply a list of Silastic SO gasket fabricators to all transformer manufacturers or users. They will also furnish technical data. See Appendix J: Seals, Properties and Procurements. C. The Older Sealing Arrangements: The older type gaskets consist of either cork or cork-nitrile rubber combinations or straight nitrile rubber. 1. Cork-Nitrile Combinetions: Cowers for the main tank, hend-holes, switch and terminal chambers, relief diaphrams, etc., are held in place by studs welded to the flange or by bolts. The gaskets are cut with openings and placed over the bolts. Often Shellac (Westinghouse Styl No, 1150419, or General Electric Company's Glyptal* 12761 is used to cement the cork to the flanges. The following is recommended for sealing with, the cork nitrile rubber combinations: Use Armstrong NC-757 cork-nitrile material or equivalent. The gasket can be cut from a single sheet or by scarfing strips of the material. A convenient method for joining strips is to make a Keystone Type joint. For this purpose, Westinghouse, Sharon, Pennsylvania, offers their gasket cutter Style No. 328 0614 G01, (about $15). The joints - and also the gasket - should be cemented to the flange, using one of the above cements. Excess cement should not be allowed to reach the interior of the transformer. After installation and bolting, the outside edge of the gasket should be coated thoroughly with epoxy cement to increase weather resistance. This epoxy cement is a paste to which a curing catalyst is added immediately before use. Typical are: a. Epoxy Patch Kit #1*C Hysol Corporation, Olean, New York b. Scotchcast** Resin *4 Minnesota Mining & Manufacturing Company St. Paul, Minnesota c. Adhesive A-1 and Activator Type B - Armstrong Products Company Argonne Road, Warsaw, Indiana d. Adhesive 9860-1, Synthetics Organic Company, Cleveland, Ohio, used with activator diethylene triamine (Carbide and Carbon Chemical Company) 2. Straight Nitrile Rubber: When straight nitrile rubber was originally used, invariably the gasket was recessed in a groove. This was to prevent gasket flow and to protect the material against excessive compression. Although this type seal was not cemented, the nitrile rubber gasket is not reuseable. Since grooves or stops have already been provided for the nitrile rubber seal. Silastic 50 can be easily substituted and is recommended. This conforms with modern practice. XVI. Periodic Fluid Inspection and What Checkpoints Mean On a regular schedule - at six, nine, or twelve-rrvonth intervals - make a simple visual inspection of your sskarel insulation and run a dielectric breakdown voltage check, Trademark of General Electric Company Trademark of Minraeota Mining & Manufacturing Company , TOWOLDMON0038384 WATER_PCB-00022853 A, Visual Inspection: Askarel is a clear, faint-yellow liquid. After long-term use this color may gradually intensify to light brown The fluid should remain clear and free from turbidity or cloudiness Any color change -- such as to a green, red or blue cast - indicates extraction of impurities (color materials) from the solid insulation, If a distinct foreign color pick-up is noted, check the complete range of electrical characteristics and notify the transformer maker. Blackening of the askarel may indicate an arcing condition. Other color changes alone are not danger signals since the dielectric breakdown voltage is not likely to be impaired. 8. Dielectric Breakdown Voltage If the dielectric breakdown voltage has decreased significantly from the.last inspection, or if it has gradua'ly decreased beiow 26 KV range (at 25*C) - RUN A CHECK FOR MOISTURE. Use ASTM D1633 (Karl Fischar Method). The dielectric breakdown voltage of askarel is the major indicator to the operating efficiency of your liquid insulation. Besides the visual inspection tests, dielectric breakdown voltage is the only test necessary to run on a routine basis. Well-sealed askarel transformers have service records of 25 to 30 years on the original askarel. XVII. Inspection Checklist 1. If askarel is clear - even though darkened to light brown, has no sediment or turbidity, has dielectric breakdown voltage over 26 KV - give it the inspection "OK". 2. If askarel is clear, but has foreign color of blue, green, red ... it is "extracting color" from internal materials. This is not, of itself, an operating hazard when the dielectric breakdown voltage stays over 26 KV and moisture remains low. However, this rare occurrence calls for checking into the condition of the interior construction end consulting the transformer maker. However, when sampling the fluid care should be taken to avoid getting color into the askarel from paint that may be inside or outside of the sample valve. 3. If the moisture content is found to be above 70 ppm at operating temperature, then sampling should be done at more frequent intervals to establish a possible trend, particularly on outdoor installations. 4. If askarel is clear, but dielectric breakdown voltage drops to 22 or lower KV, and moisture rises over 80 ppm when sampled at operating temperature ... the askarel is ready for simple "refining", If the moisture is near the saturation level (about 125 ppm at room temperature) a thorough inspection should be made for water droplets in the transformer tank, and evan for "globules" of water floating on the askarel surface. If found, the transformer manufacturer should be consulted for reconditioning both the transformer and the fluid. 5. If askarel is dark brown to black, if black part des of carbon are seen, and dielectric strength is low . . . the askarel has been broker down by arcing. It cannot be refined and should be removed anc incinerated under proper conditions. (See ANSI Committee C107 report on Use and Disposal of Askaral and Askarei-Soaked Material?. 1430 Broadway, New York, New York 10018. If any of these five simple inspection tests appear out of the ordinary or the relationship between appearance and test values s abnormal, contact your transformer supplier for a complete analysis. Whenever a sample is to be shipped to Monsanto, please follow the directions shown under: "SAMPLING ASKAREL1'. TOWOLDMON0038385 WATER_PCB-00022854 XVIII. Contamination in Transformers Moisture, particulate matter and arced decomposition products are known to be serious contaminating influences on transformer askarel. The power factor test normally used for the detection of contamination In mineral oil filled transformers is of little use for this purpose in askarel filled transformers, due to tne extreme effect of extraneous soluble polar materials. This increase in power factor as illustrated in Tibia VI has no adverse effect on dielectric breakdown voltage. Table VI Effect of Common Insulation Materials on Powar Factor end Dielectric Strength (Heat Aged 96 Hours in Askarel at 100*C.) Material Immersed Askarel After Exposure Power Factor, Percent at 60 eye.. 100*0 Dielectric Strength 25*C. None (control) Black varnished cloth Copper Pressboard Manila paper Phenol formaldehyde resins Shellac Iron Synthetic rubber ' 1.0 86.0 1.S 2.0 1.6 1.6 6.0 5.0 70.0 35 KV 42 40 37 39 41 36 39 39 Similarly, trace contaminants from commonly used construction materials can lower the volume-resistivity of askarel, without affecting its dielectric breakdown voltage. This is shown in Table VII. Table VII Effect of Common Insulation Materials on Volume Resistivity of Askarel Semple Volume Resistivity x 109 ohm-cm (at 100*C., 500 Volts DC., 0.1" gap! 1. New askarel before heat aging 2. New askarel after heat aging 96 hours at IO0*C 3. After heat aging with 1 sq, inch specimens of: a. Phenolic resin tap changer material b. Paper c. Grade A prtssboard (tan) d.Grade A pressboard (gray) e. Grade A pressboard, laminated strip ' f. Cotton wrapping g. GlypteM 276 cement, cured 48 hrs. at 110*C 2,000 1,900 1,200 750 500 500 400 300 100 While trace contamination easily lowers volume resistivity from high levels, it is important to note that heavy contamination (as when arced) does not lower the resistivity below the order of 109 ohm-cm. at 100*C. Tha different behavior of askarel vs. mineral oil in these respects can be summarized as follows: High power factor and low volume resistivity in transformer mineral oils ere commonly regarded as "danger signals" that the oil has deteriorated end broken down chemically or excessive moisture is present. This is NOT TRUE of askarel liquid insulation unless the dielectric breakdown voltage is low or the moisture content is high. QblHtQb TOWOLDMON0038386 WATER_PCB-00022 Manufacturers of askarel type transformer? point out that it \\ quite well known that askarel transformers with initial power factor of the askarel fluid in excess of 50% et room temperature and 60 Hz are giving satisfactory service life. However, there needs to be assurance that both dielectric breakdown voltage and moisture are at satisfactory levels and do not show adverse trends. XIX. ASTM D3255 Method For Investigating The Compat ibility of Transformer Insulation and Construction Materials in Askarels This method uses the change of electrical and/or chemical characteristics of transformer askarel resulting from its controlled exposure to insulation and construction materials, in order to evaluate their immediate major "contamination" effect on the askarel fluid. Delayed or long time contamination affects may not be detected. The method also utilizes various physical tests on the insulation and construction materials after controlled exposure to the askarel to determine the compatibility of these materials with transformer askarel. Properly proportioned specimens of the insulation or structural materials are immersed in refined askarel for 168 hours at 109 + 1*C in a forced draft oven. Changes in electrical and chemical properties of the transformer askarel are compared against a control sample of the askarel treated in the same manner, in absence of the test specimens. Dissipation factor (ASTM D 924) change is one of the criteria used The askarel fluid is refined by absorptive treatment to a dissipation factor level of 0.05 max. at 100*0 and 60 Hz and 0.01 max. at 25*C and 60 Hz. Corresponding values of the askarel fluid after heating 168 hours at 100*C in absence of a test specimen are 0.075 and 0.02 respectively The maximum dissipation factor levels suggested for the askarel after heating in presence of the test specimen are 0.20 et 100*C and 60 Hz and 0.04 at 25*Cand 60 Hz. XX. Refining Askarel for Reuse A. Filtering Through Dry 3lotter Paper to Remove Moisture and Extraneous Particles: Most operators prefer portable refining apparatus, such as a plate press fitted with a dolly, available from Sparkler, Mundelein, Illinois or General Electric Company, Pittsfield, Massachusetts: or the earthen cartridge filter type available from Industrial Filter Corporation, Lebanon. Indiana. Filter paper liners for the plate press are available from Carl Schleicher and Schuell Company, Keane, New Hampshire and manufacturers of filter presses listed above. The filter paper must be dried immediately before use. For best results, spread the paper for maximum surface exposure m a hot air circulating oven and heat it for 4 to 6 hours at 110*C. Circulate the askarel hot (but not over 40*0 through the *-iter fitted with the dry paper liners. After filtration the dielectric breakdown voltage of the a$<arei should be 35 KV minimum. PRECAUTIONS: 1. Filtering should not be done when the relative hum d exceeds 75%. 2. Any flexible hoses and gaskets on the refining equipment should be lined with or made of materials that will not be softened by contact with askarel fluid. (Materials lined with Silicone, Viton or Teflon* or flexible metal materials are suitable.) Trademark pi E. I. DuPont DeNempuri a< Company, tnc. 061^ 206 TOWOLDMON0038387 WATER_PCB-00022856 TABLE VIII Quid* to Rot* of Dissolved W*t*r Removel By Filtering Askarei Through Paper Pri> Passes Through Paper Press Water in Askarei PPM 0 115 1 35 2 22 3 18 4 12 5 10 6 10 8. Dlspoaai of Solid Wastes: The ANSI guide C107.M974, Section 4.1.6 gives detailed recommendations, C. Solid Insulation Reauiring Drying: If the solid insulation of the transformer requires drying, consult the transformer manufacturer or an apparatus service shop, as in such case oven drying is preferred. D. Earth Treatment for Maximum Improvement of Power Factor and Volume Resistivity: We question whether pumping and filtering thB fluid solely to achieve a change in power factor or volume resistivity alone is justified in today's ecological climate regarding PC8$. We recom mend that in these situations the original transformer manufac turer be contacted. 1. Procedure: The askarei liquid should be relatively dry p;ior to the following earth filtration. As e coating on the filter paper surface use finely divided Attapulgus* clay or Fuller's earth dried and activated by heating for 12 hours st 300-350T immediately prior to use. The amount of earth used should be 0.1 to 0.2 percent by weight on the weight of the askarei to be treated. Askarei weighs about 12.5 pounds par gallon. To deposit the earth evenly, stir one-third of the earth with a small portion of askarei in a clean container. Pump the mixture through the filter and follow with two more one-third portions. Then circulate askarei taken from near the top of the transformer, past it warm (not over 55C) through the earth-coated filter and feed back through the bottom transformer outlet. Continue circulation until the fluid is clear and test shows that tha electrical properties are fully restored. 2. Effect of Earth on Removal of Scavengers Only slight and insignificant loss by selective absorption of tin tetraphenyl and epoxides occurs when askarei is refined by treatment with 0.1 to 0.2 percent by weight of earth. To remove significant amounts of the scavengers requires repe titious treatment with much larger amounts of earth. 'Trademark of Engaihard Minerals and ChamicaitCorp. 06U207 TOWOLDMON0038388 WATER_PCB-00022857 Table IX Approximate Relationship Showing th Insignificant Effect of Power Factor and Volume-Reiietivity on Dielectric Breakdown Voltage of Transformer Askarel Power Factor (60 cvc.) OO-S" "25=5 Volume Resistivity x 109 ohrrvcm (at 100*0,500 Volts DC. 0.1" aao) Breakdown Voltage 25*C, 0.1" gap 2% 65% 15% 20r26% 40-50% 0.05% 0.1% 0.7% 2.0% - 1500 500 100 60-70 25 36 KV 35 35 35 35 XXI. Cleaning Arced Transformers If a unit has arced so that the askarel is no longer fit for use, a thorougl cleaning of the unit is necessary before refilling with new askare insulation and returning it to service*. Follow this procedure insurin' care is taken to prevent any loss of liquid askarel to effluent stream? A. Drain out all dark, carbon-contaminated askarel. Arrange to hav the scrap fluid incinerated under proper conditions. (See ANf Committee C107 report.) B. Carefully brush carbon deposits from internal parts and insulatio> using a soft bristle brush making sure that insulation is no damaged. C. Flush thoroughly using new askarel - nor an oil, nor a cleanm solvent. D. Flush a second time with fresh askarel; drain; then fill to the proper level with new askarel. E. Energize transformer to warm the fluid for 24 to 48 hours; then circulate the askarel through a filter, returning it to the unit filtered and ready for use. XXII. Sampling Askarel Take a sample as close to the top of the liquid surface as possible. Many arge askarel transformers have a built-in sampling tube near the surface for convenient sampling. Then, to make sure that your sample truly represents your askarel insulation, take another sample from the bottom. If additional sampling tube connections are contrived on thr valves for easier sampling, make the tubes of clean glass, stainless steel aluminum or tin for rigid types; and silicone, or Viton or Teflon tubmr for flexible types. Use NEW containers for the askarel sample. A new and thoroughly pre-dried. small-mouth quart glass bottle fitted with e Bakelite** screw cap with aluminum or tin cap liner is recommended for quick, on-nte testing. (If complete analysis is to be made, a 5-pint size sample i< required.) Be sure that the new bottle does not stand open to collect dust c moisture. Rinse the sample bottle and cap lining two or three ume* with askarel from the transformer, then fill it. If the sample will t> tested promptly, a clear glass bottle can be used. If sample is to b> stored indefinitely, use an amber glass bottle or wrap clear glass wit" aluminum foil. A. Select a dry day. Do not sample insulation on a warm, moist da\ when humidity exceeds 75%, and . . . This assumes that the causa of arcing has been established and corracnoni modi Whan levere arcing occurs, major repairs are usually necessary and the un rebuilt. This procedure can be applied for flushing out the repaired units. TredemarK of union Cirbide Corporation 06 lA^Od 17 TOWOLDMON0038389 WATER_PCB-00022858 B, Make sure that the askerel is at least as warm at the surrounding ir. (Cold liquids can condense moisture from humid air.) C. When sampling askerel from transformers, it is best to take the sample when the unit is warm and operating at average or maximum load, especially for a check on moisture as reflected by dielectric breakdown voltage test. Sampling the warm askarel more truly represents its condition during operation. Experience shows that water will migrate from a transformer's solid insulation to the askarel liquid and vice versa, depending on temperature. Therefore, when the transformer is hot, the moisture is most likely to be found in the liquid. This accounts largely for periodic variations in dielectric breakdown voltage. For example, a relatively high dielectric breakdown voltage may be found during winter months and a relatively low dielectric breakdown voltage during the summer months on samples taken from the same unit. When testing has been completed, the remainder of the fluid simple should be destroyed by high temperature incineration described in Section VIII. TOWOLDMON0038390 WATER_PCB-00022859 Askarel Filled Switches and Terminal Chambers I. Introduction High voltage leads are usually connected to askarel or mineral oil-filled network transformers and power centers through terminal chambers and switches. In some cases terminal chambers are not used, end the high voltage leads are connected directly to the switch terminals. They may be filled with either askarel or mineral oil. Switches are usually rotary or drum type fitted with a revolving block and porcelain unit as the principal element arranged for three-phase service. Askarel transformers with attached switches have been in use for about 30 years. When they were first introduced, the availability of insulating and gasketing materials was rather limited and even the best materials at the time had no service history. As a result, inadequate gasketing materials such as cork, nitrile rubber, and nitrile rubberendcork particles were used. While satisfactory for a limited period of time, these materials cannot be depended upon for the expected long life of the equipment. The terminal chamber is usually above or below the switch compartment and separated by a steel wall through which the bushings are inserted. When bushings are properly selected and correctly installed, there is no leakage from one compartment to the other. With poor bushing seals, and the terminal chamber above the switch, potting compounds or cable oil can seep into the askarel. When the terminal chamber is below the switch, askarel can drain into the terminal chamber. II. Sources of Contamination There are three possible sources of contamination for askarel in switches and terminal chambers; they rank m this order of frequency: (1) water entering through poor gaskets; (2) decomposition products from arcing when switch is used to break magnetizing current; (3) entrance of pothead or cable compounds through leaky bushing seals. Unlike an askarel transformer where the amount of contaminant is likely to be very small (probably only trace amounts) in relation to the volume of askarel fluid - in switches or terminal chambers with faulty seals, the amount of contamination can be relatively large. Experience has shown that, based on the number of installed askarel-switch units, the percentage of failures is extremely small. When investigated, it has been found that most failures originate in the switch chamber. Water is the chief source of contamination, However, heavy contamination of askarel with petrolatum end asphalt material, due to leakage, have caused a few failures. Petrolatum is used frequently for filling terminal chambers. When either cable oil or petrolatum seeps into askarel. no great harm results. The firs resistance will be somewhat decreased and power factor of the askarel will increase with an accompanying drop in resistivity. While highly undesirable, it is doubtful that failure of the unit results, Where asphaltic compounds are used in place of petrolatum, the danger is increased somewhat because asphaltic contamination may cause excessively high dielectric losses in the askarel. When the terminal chamber is below the switch chamber, the potting compound can be contaminated by askarel if the bushing seals are leaky. This is undesirable because the askarel will increase the power factor and conductivity of the potting compound or cable oil ana develop heat from dielectric loss. If this mixture is drawn into the cable 061^10 TOWOLDMON0038391 WATER_PCB-00022860 Insulation, a cable failure is likely. This again emphasizes the Importance of tight bushing assemblies. III. Sealing Switches and Terminal Chambers Proper bushing construction, use of Silastic seals and welding wherever possible is highly desirable las covered in Section A). Where an elastomeric seal is to be used in contact with both askarel and petroleum oil, DuPont's Viton is suggested. For new equipment the user should specify these modern sealing arrangements to keep out contaminants and minimize maintenance. IV. Askarel Used Under Mild Arcing Conditions The IEEE Guide for Transformer Askarel calls attention to the following: "Askarel is used, to some extent, in apparatus where it >s subjected to light intermittent arcing, such as in self-contained induction regulators, where operating switches are continually producing slight arcs, in transformer de-energizing switches, etc.. Under normal conditions, deterioration of the askarel is very slight. However, improperly adjusted or defective switches m this type of apparatus can produce excessive and prolonged arcing and accelerated deterioration of the askarel. It it recommended that when askarel is used under these conditions, checks of the liquid, especially for moisture and dieleetric breakdown voltage made more frequently than when it is used only as a cooling and insulating fluid. Deterioration of this type is indicated by a blackening of the liquid. It can usually be reconditioned as previously described. Special attention should be given to maintaining the scavenger at the appropriate concentration." V. Maintenance for Askarel Filled Switches A. Switches used for grounding after power source has been de-energized will not undergo arcing. B. Switches interrupting magnetizing current will be subject to arcing; the amount of decomposition will depend on power interrupted, time and frequency of operation. As a general rule, the liquid should be checked after 6 to 10 operations. 1. On newly installed switches, check the askarel at 3.6 and 12 month intervals; if found satisfactory, check once annually thereafter. With proper attention to the gasketing of covers and bushings, experience will probably indicate that less frequent inspection is warranted. . 2. Check askarel for: a. Dielectric breakdown voltage (ASTM D677): It should be 26 KV minimum. If dielectric breakdown voltage is low, confirm presence of water by Karl Fischer method ASTM D-1633. Filter to remove moisture. Dielectric strength should then be 30 KV minimum, b. Presence of carbon from arcing: Fluid should be relatively free of carbon, If badly arced and very black, replace fluid. If only minute amounts of carbon are present, filtration is recommended. Check power factor of liquid (should not be over 6% at 26*C and 60 cycles). Flush out switch chamber with several gallons of fresh askarel before refilling. ' 3. If there is discoloration, high power factor, detectable change in specific gravity or refractive index, or if fluid flashes below 25CFF, there is a possibility of seepage of potting compound into the switch compartment. In this case, correct any leaky bushing seals with proper replacements and fill with new askarel, 4. If terminal chamber is below switch, check potting compound for presence of askarel (can usually be detected by odor or by an increase in specific gravity) If askarel is present, correct any leaky bushing seals with proper replacements, and renew compounds. 5. Examine cover gaskets visually. Deterioration can be detected Q6U2U TOWOLDMON0038392 WATER_PCB-00022861 by welling and cracking of the exposed edge. In case* of severe deterioration, liquid seepage is usually present. 6. Check for leakage at packing gland of switching shaft, if leaking, repack with a Silastic ring type gasket, VI. Askarel Under Excessive Temperature or Fault Conditions The IEEE Guide also points out that, "Chlorobenzenes used in transformer askareis begin to boil at temperatures of about 205'C, under atmospheric conditions. If the material is heated to such high temperature m a sealed system, pressure develops. Pressure will also develop in the system if the askarel is arced sufficiently to generate copious hydrogen chloride gas. 'Therefore, it Is recommended that wherever possible, seeled askarel-filled equipment be provided with pressure relief devices, These devices must be large enough to provide immediate relief at a definite pressure, and to prevent further build up of pressure it decomposition continues. It must be remembered that the presence of devices of this sort does not necessarily preclude the rupturing of containing vessels, since pressure build up can be extremely rapid under violent arcing conditions." Toxicity & Safe Handling I. Inhalation At ordinary temperatures the chlorinated biphenyls in Askarel have not presented industrial toxicological problems. The hazard of potentia toxic exposure varies with their volatility: the lower-chlorinated, morevolatile ones present more of a potential problem from the standpoint of both inhalation and skin contact. When Askarel fluids are used at elevated temperatures, engineering controls must be applied, either by the use of closed systems or by effective local-exhaust ventilation together with general workroom exhaust. Vapors of Askarel at room temperature should not be breathed m a confined space, and no vapor of any fluid evolved at elevated temperatures should be allowed to be dispersed into the general workroom. Inhalation tests on animals indicate that the maximum safe concentra tion of vapor is in the range of from 0.5 to 1.0 milligram per cubic meter of air. The threshold limit value (maximum allowable concen tration of an 8-hour working day) set by the American Conference of Government Hygienists are 1,0 milligram of the lower-chlorinated biphenyl compounds per cubic meter of air and 0.5 milligram of the more-highly-chlorinated compounds, per cubic meter of air. it. Skin Contact Prolonged or repeated skin contact with the Askarel fluids must be avoided by the use of gloves and protective garments, beceuse of the possible occurrence of a condition called chloracne. Although reports of this condition caused by Askarel are rare, it can be produced bv excessive skin contact. If the fluid is spilled on the skin the skin should be washed in the usual manner with a soap solution. A burn caused by contact with a hot Askarel should be treated like any ordinary burn. For disposal instructions of Askarel fluids, see Section A VIII, page 6, 061*212 TOWOLDMON0038393 WATER_PCB-00022862 Analytical Services on Transformer Askarel Available From Monsanto Transformer users not wishing to make thair own fluid analysts can obtain tha sarvica from Monsanto. Simply contact Monsanto and specify what analysas art wanted. You will be sent the propar-siied, clean sample container, fitted with a proper label. When you receive this, carefully take your sample (following the procedure for sampling in this guidei. Send the container to Monsento's laboratory. Charges lilted Include sample container end laboratory costs. The charges are those in effect March 1. 1976, and are subject to change. Typat of Analysts Available Analysis 1) ROUTINE MAINTENANCE CHECK Total Charge: $30.00 To dattrmine tha genaral condition of tha fluid and find whether further analysis is necessary, (one-quart sample required) Properties Tested . Dielectric Breakdown Vdltage Color and Condition ' Moisture You will be notified of the results of this test. If further testing is indicated, and you want a complete analysis, you will be sent a flve*pjnt sample container. This sample will be usad for the following series of tests: Analysis 2) COMPLETE ANALYSIS Total Charga: $76.00 (1) To determine tha extant of fluid contamination, (2) earth refinement to determine what degree of restoration of eiectncai and Insulating proparties is possible, (3) check test to sea how the fluid responded to earth treatment. a) Complete Analysis: to determine tha extent of contamination Properties Tested Free Chlorides Color and Condition Acidity Specific Gravity Dielectric BreakdownVoltage Refractive Index Power Factor, Dielectric Constant, and Resistivity Water b) Earth Refinement Response: Consists of treatment for 2.6 hours at 60-60%. with 0.1 to 0.2 percent by weight of properly conditioned Attapuigus ciav and than filtration through dry filter paper. c) Analysis After Laboratory Earth Refinement: Properties Tasted Acidity Refraotive Index Dielectric Breakdown Voltage . Water Power Factor, Dielectric Constant, and Resistivity Free Chlorides You will be notified of the results of this test series on your sample. Then after refining your entire transformer fluid fin yo. can chtck on tha rasults by requesting the following analysis: Analysis 3) ANALYSIS AFTER EARTH REFINEMENT Total Charge: $50.00 (Thia charge will not apply whan analyses 1 and 2 have already been made.} To determine whether tha antirt lot of me askarel till responded to the same extent as the laboratory sample, (five-pint sample required} Properties Tested Free Chlorides Color and Condition Acidity Refractive Index Dielectric BreakdownVoltage Water Power Factor, Dielectric Constant, and Resistivity To arrange for the tests described above write to the following address: David Wood Monsanto Industrial Chemicals Company 800 North Lindbergh Blvd. St. Louis, Missouri 63166 Simples to be tested should be clearly marked for identification and sent directly to: Monsanto Company W. G. Krummrich Laboratory Sauget, Illinois 62201 Attention: R. Kuiter 0bU213 I TOWOLDMON0038394 WATER_PCB-00022863 Appendices APPENDIX A Askarel Stability and Composition of Arc Formed Gas: Askaral insulation is one of the most inert, chemically-stable heat resistant, non-corrosive liquids known. It will not break down, oxidize or sludge when exposed to air and high temperatures, 160*C. or even somewhat higher. Arcing, however, will break down the compound to liberate some hydrogen chloride and small amounts of carbon. APPROXIMATE COMPOSITION ARC-FORMED GAS FROM TRANSFORMER ASKAREL BLENDS ASTM TYPES D AND 0 (INERTEEN 70-30 AND PYRANOL A13B38-3, RESPECTIVELY) Gaa carbon monoxide carbon dioxide oxygen inert gases hydrogen chloride (note the absence of phoegene) Amount 0.3% 0.3% 0.6% 1.5% 97.3% This arc-formed gas from ASTM Type D and Type F transformer askerels is non-flammable and non-combustible. For all practical purposes, the amount of gas liberated from askarel under a given set of arcing conditions is about 100 cubic centimeters per kilowatt-second. APPENDIX B_________________________________________________________________ SOLUBILITY OF GAS IN TRANSFORMER ASKARELS ASTM TYPES D AND G APPENDIX C Carbon dioxide Air Nitrogen Hydrogen chloride* Mn absence of scavenger Percent of Gas By Volume Corrected to: 25*C 760mm 0*C.760mm 25*C 100*C 25*C 100*0 71% 6.7 6.0 37.8 47% 4.9 4.8 50.9 __ 6.8 6.0 6.6 4.4 -- EFFECT OF TEMPERATURE ON DIELECTRIC BREAKDOWN VOLTAGE OF ASKAREL Temperature *C -60 -40 -20 0 20 40 60 80 Dielectric Breakdown Voltage ASTM 0877 67 KV 63 67 55 60 50 48 45 06142X4 TOWOLDMON0038395 WATER_PCB-00022864 APPENDIX P COMPARISON OP THE APPROXIMATE VISCOSITY IN SAYBOLT UNIVERSAL SECONDS OP TRANSFORMER ASKARELS AND MINERAL OIL Temp. *C -20 0 20 40 60 80 100 . Pyranol AI3838 3 1.000 100 70 46 39 34 30 . 10-C Mineral Oil 1,000 160 85 49 40 34 30 inerteen 70-30 2,800 196 86 50 40 36 33 APPENDIX E Temp. *C 0 20 40 60 SO THE DENSITY OF INERTEEN 70-30 AND TRANSFORMER PYRANOL A13838-3 Approx. Density gm/ce. Inerteen 70-30 1.574 1.552 1.529 1.507 1.486 Pyrenol A1383B-3 1.577 1.655 1.532 1.510 1.488 APPENDIX F The thermal conductivity valuas of transformtr Pyranol A1363B-3 at 27*C and 58*0 arc 26.2 and 26.8 x 10'9 calories oantimeterri, degrees centigrade**, second**, respectively. Or. approximately 0.06 BTU par (hr.) (sq. ft.) (*F.) par foot. Thli lama approximation ippliaa to Inerteen 70-30. APPENDIX Q____________________________________________________________________________________ Haat Capacity 6ver the tamparature range of 26* to 126*C the specific heat of transformer eskaret is close to 0.30 calories par gram per degree. APPENDIX H____________________________________________________________________________________ Coefficient of Expansion The average eocfflcientof expansion of transformer aikarei over the temperature range20 to 100*C n0.0007 ce/cc/'C. One gallon would Increase to 1.066 gallons on heating from 20 to 100*C. APPENDIX I Fire Resistance Aikarels of various compositional types are used. Under arcing conditions the gases produced, while consisting of predominantly non-combustible hydrogen chloride can yield varying amounts of combustible gases depending upon the esksrel type. . Insulation systems incorporating these eskarels and ceiiulosic or other organic materials may. whan arced, produce gaseous mixtures which are moderately flammable. As a precaution, such gases should be removed from the askarel by bubbling dry nitrogen through the aakerel end flushing the gas space with dry nitrogen before any work is performed on the epperatut. i 1 , 061^15 TOWOLDMON0038396 WATER_PCB-00022865 APPENDIX J Still, Properties ind Procurement Dow Corning Corporation, Midland, Michigan with Districts at Atlanta, Boston, Chicago, Cleveland, Oallas, Los Angeles, New York City, Washington, D.C. and Toronto has available Bulletin 09-019, August 1962 entitled "Silastic Design Data"! This lists the gasket fabricators throughout the country from whom the "Silastic 50" gasketing can be purchased in sheet, extrusions or molded shapes. Generally, Silastic 50 sheet goods are stocked by local die cutters, hence, could be generally purchased locally. Usually small quantities of gaskets are die cut. If larger quantities are needed, tools are made of the same type used to cut other elastomers. Where the gasket is extruded for fitting into a machined groove or between gasket stops, Dow Corning advises use of a scarved joint. This joint is then cemented using Dow Coming's Silastic 140 (clear) or their RTV 731 (white) materials, which air cure. Dow Corning points out that the local "rubber" fabricators purchase the Silastic 50 in billet form. This is worked on a roll mill in preparation for shaating or extrusion. Then to obtain the desired physical properties the fabricator must oven cure the Silastic 50 for 24 hours at 480*F. SPECIFICATIONS* ASTM 0676 ASTM D412 ASTM 0412 ASTM D396 Color Specific Gravity at 77*F Hardness, Shore A. Scale Tensile Strength, psi, min Elongation, percent, min Compression Set after 22 hrs at 300*F, percent, max White 1.20+0.02 45 to 60 800 250 30 * All physical properties measured on 0.075 inch thick samples molded 5 minutes at 240*F, and oven cured 24 hours at 480*F, APPENDIX K_____________________________________________________________________________________________________ Caution Label The following or equivalent caution statements should be fixed on all containers of transformer askarels and the transformers themselves: This product contains Polychlorinated Biphenyls (PC8s). Care should be taken to prevent entry into the environment through spills, leakage, use, vaporization, or disposal of liquid or containers. Avoid prolonged breathing of vapors or mists. Avoid contact with eyes or prolonged contact with skin. If skin contact occurs, remove by washing with soap and water. Following eye contact, flush with water. In case of spillage onto clothing, the clothing should be removed as soon as practical, skin washed, and clothing laundered. Monsanto MONSANTO INDUSTRIAL CHEMICALS COMPANY SPECIALTY PRODUCTS GROUP SOON. LINDBERGH BLVD. ST. LOUIS, MISSOURI 63166 The information herein regarding obtaining optimum results from askarel fluids m your transformer has been accumulated by Monsanto for over 40 years from the experience of makers and users of askarel transformers and it is believed will be helpful. Nothing herein shall be construed as applying to other than askarel insulation. Dat8 and maintenance suggestions herein do not apply to the other components of the trBnsformer. All operating and maintenance suggestions recommended by the manufac turer of the transformer should also be carefully followed. Because these maintenance directions apply only to the askarel insulation, Monsanto disclaims any liability for damage to property or injury to persons arising from transformer operation. 0614216 TOWOLDMON0038397 WATER_PCB-00022866 0 S CUSTOMER SERVICE CENTERS AKRON. OHIO 44313 260 Spnngaida Driva Montrom DavVopmant Pmk Tv. (216)6994111 ATLANTA. GEORGIA wyff 320 Intantata Nor* Vitim Sum 500 7# 14041 434-4949 BOSTON MASSACHUSETTS 49149 Evarati Station Ti. 1617)387-4010 HOUSTON. TEXAS 77497 1301 Port Oak Tonar S061 Watthalmar Road Trl. 1713)621-9990 LOS ANGELES. CALIFORNIA 1401 Do** Straat Newport Baach, CVHomta T*t 1714)433-9190 NEW YORK, NEW YORK 10994 11114 A vanua of tha Amariem TV. 1212) 764-6000 ST LOUIS, MISSOURI 43194 900 N Lmdbargtr BWd. TV. 1314) 694-1000 SAN FRANCISCO SAY AREA 2710 Latayatta Santa Clara. California 9949 TV. (408) 243-0414 WILMINGTON. DELAWARE I Sum 204. Bancroft 9m, 3411 Silvaratda Rood Tat. 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