Document OER4N9kk4BJoe580e52Kb2rNL

BULLETIN NO. IC/FF 38R (Revited Merefi. 1975) TRANSFORMER Inspection & Maintenance Guide Monsanto TOWOLDMONOOQ2828 TMkfl ff (Ccmfemfe SECTION A .1 I. .1 II. Table I - The Composition of .2 III. Interchangeability .................................. IV. Table II - Official Transformer Adcaral .3 V. VI. VII. Precautions When Handling Drums, Tank Cart Table III - Handling and VIII. IX. X. XI. XII. XIII. XIV, XV. XVI. XVII. XVIII. XIX. XX. A C. Precautions on Opening an Askarel Transformer........................................ 5 Avoid Environmental Pollution........................... S 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 R epair or Scrap.........................................7 5. Transformer Disposal......................................7 Expected Service Life...........................................7 General Characteristics of Transformer Adcarel Fluid.......................................................... 7 Sampling Transformer Adcarel Fluid .................B Evaluation of Adcarel Received in New Equipment................................................8 Dielectric Breakdown Voltage Moisture Relationdlip.......................................... 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 endAflineral Oil .... 10 Turbidity ............................................................. 10 Check Points for Maintaining Adcarel Insulation .............................................. 10 A. General Considerations................................. 10 B. Modern Sealing Procedures ......................... 11 C. The Older Sealing ArcJOpments................. 12 Periodic Fluid Inspection and ' What Checkpoints Mean ....................................12 A. Visual Inspection........................................... 13 B. Dielectric Breakdown Voltage ....................13 Inspection Checklist........................................... 13 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 ASTM Method for Investigating the Compatibility of Transformer Insulation and Construction Materials in Adcarels............IS Refinlng Adcarel for Re-Usa.............................. 15 A. Filtering Through Dry Blotter Paper to Remove Moisture and Extraneous Panicles...................................... IS XXI. XXIL Tab!* VIII -- Water Removal by Filtering Askarel Through a Paper Press ............... B. Disposal of Solid Wastes........... C. Solid Insulation Requiring Drying . D. Earth Treatment for Maximum Improvement of Power Factor and Volume Resistivity ...................... .16 3 Table IX - Effect of Power Factor and Voluma Resistivity ............. Cleaning Arced Transformers................. .17 Sampling Adcarel................................ SECTION B ASKAREL FILLED SWITCHES AND TERMINAL ;HAMBERS ........................ .19 1. II. III. Introduction...................................... Sources of Contamination .................... .19 Sealing Switches and Terminal Chambers . . .20 IV. Adcarel Used Under Mild Arcing Conditions .20 V. Maintenance for Adcaral Filled Switches . . . .20 VI. Askarel Under Excessive Temperature or Fault Conditions ............................ .21 SECTION C TOXICITY AND SAFE HANOLING..............................21 I. Inhalation............................................................ 21 II. Skin Contact....................................................... 21 SECTION D ANALYTICAL SERVICES ON TRANSFORMER ASKAREL AVAILABLE FROM MONSANTO................................ 22 Types of Analyses Available: ........................................... 22 1) Routine Maintenance Check.................................... 22 2) Complete Analysis.................................................... 2^ 3) Analysis After Earth Refinement ........................... 2fl SECTION E APPENDICES.................................................................... 23 Appendix A - Askarel Stability and Composition of Arc Formed Gas..................................23 Appendix B -- Solubility of Gas in Transformer Askarels .....................................................23 Appendix C - Effect of Temperature on D ielectric Breakdown Voltage of Askarel ...................23 Appendix 0 - Comparison of the Approximate Viscosity in Saybolt Universal Seconds of Transformer Askarels and Mineral Oil.......................... 24 Appendix E -- The Density of Ineneen S4201 KA 7336-9 and Transformer Pyranol A1383B-3..........................................................24 Appendix F -- Thermal Conductivity Values of Transformer Pyranol A13B3B-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 in 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 uoAK on contained information or recommendations, and claims all liability for any resulting loss or damage." 6BRN 001051 TOWOLDMONOOQ2829 Transformer Askarel I. Introduction . Th term "askarel" as defined by IEEE. ASTM end the Nstional Bectricel Code generelly decribet e broed dess of fire-resistant* tynthetic chlorineted hydrocarbon insulating liquids widely used in transformers, reactors and accessory equipment operated at power frequencies. Askarels of various compositional types are in use. (For the general properties and types mo ASTM 0-2283.) 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 it based on facts gathered by Monsanto over 40 years at 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 and 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 and the contributions of certain data by the following: Edward L Raab -- General Electric Or. T. K. Soat - Westinghouse Electric II. History of Trade Nam* Types "Askarel" is the generic name for the fire-resistant liquid insulation end coolant first used by General Bectric Company in 1932 for their Pyranol1 brand name fire-resistant transformers, Westinghouse Electric Corporation uses their brand name, Ir.v'teen,1 Whatever the trademarked brand, the askarel contains chlorinated biphenyl -- one of the best liquid insulations developed by science. This inert material is chemically stable, fire-resistant, heat stable, non-corrosive, and has hi^i dielectric strength under the operating conditions encountered in transformers. In addition to manufacturing Arodor* (chlorinated biphenyl), Monsanto also mixes this dielectric fluid with chlorobenzenes to produce the presently used Inerteen and Pyranol blends described in Table I. "NOTE: Materials designated fire resistant' generally ere more difficult to ignite, or once ignited, bum at e dower rate titan correswnding conventional metriels. This term does not mean diet fire retittent materials will not burn. However, when properly uaed, Monsanto! fire reeisunt ASKAREL FLUIDS ere useful in helping customers meet their fire safety requirements." *Tredsmart of General Electric Company "Tradtntark of Westinghouse Electric Corporation Rapstarart trademark of Momenta rnmpwty 6BRN 001052 TOWOLDMONOOQ2830 v^w*. y*; ..V...w *i - ,'I*V * .. - TaMe4 . : . The Composition of Typical Transformer Adcarals Inpedients (X by wt.) . ' Arodor 12S4, chlorinated biphenyl (54% chlorine by weight) 70-60 Arodor 1242. chlorinated biphenyt (42% chlorine by weight) -- 100 -- Trichlorobenzene 30 . -- 40 ffienoxypropene oxide scavenger 0.18 to 0.22 0.18 to 0.22 -- Diepoxide scavenger -- -- 0.115 to 0.135 ASTM Method 0-2283, titled "Chlorinated Aromatic Hydrocarbon (Atkareitl For Traniformarx", alio lists the composition of all transformer askarels used at various times since 1932. Monsanto manufactures similar transformer askarel fluids in England wders the trade name Pyroclor is used. III. Interchangeability In general all transformer askarels are interchangeable. However, it it suggested that the transformer manufacturer be consulted prior to mixing in significant proportions or total substitution. IV. Transformer Askarel Specification* Specifications for the three modem transformer askarel fluids are shown in Table II. V. Ordering Instruction* Monsanto's current policy is to sdl askarel transformer fluids only to transformer manufacturers. Others interested in these fluids should contact the manufacturers of askarel transformers and not Monsanto. The transformer name plate indicates the transformer maker and usually gives suffident data to identify die specific askarel fluids usad. ^ `f! VI. Contamination ' Askarel insulation mutt never be mixed with mineral oil. Over two percent of mineral oil by volume in askarel begins to lower its fire resistance. . ' ' In modem transformers, the principal "enemy" of askarel it contamination by water. Keeping askarel water-free will insure long-time service. .. ' Askarel is heavier than wetar. If wettr gets into askarel insulation, only a tiny amount (approximately 12S ppm) dissolves - the rest floats on top. Askarel is very insoluble in water, only about 200 parts per billion of askarel dissolve in wetar, at normal temperatures. - VII. Precautions When Handling Drumt. Tank Cart, and Whan - . ' . Opening Transformers . . .. ` ... The foliowing are significant precautions: 1 . ' . A Keep Dry During HandTmg: In handling storing sampling and impacting askarel - and in .. "' *T h ii dcu It bttod upon ttm p ltt ta tttd in Ih t laboratory and it nol oaramtad lor all mmpUt. W rllt ut lor complata M itt Mtcifteationa for A ffctrtf ffukft. o "i wn Ml SsSp. i! e;> we S S OOjdS^ "ofl <= Jg ^i o ' o fi 8 fife J i;i5i2a o o sssl ris *5i a il k.in i*3iE |Ie;> *N iia Sgs* - s 2 <s < | | s <1 !!%to 8 i 5 3|| 118? |2 S |* E fe. "|f g> ? fS w8q* I*-!! <3 s .rigs s- |Sl3gs 8 w o j 2 * ** ~ O S3 2<g ISono * ajjn 2 -*?$ u oM j, 3 -- sk 2 ?E*1> 8 m-=0 1" 1 Si8 1 il :22r2* - s ^VilnfHgn to z , f ?-------- jfilS|S "V- v``. ** ** r7"** .+*? CBRN 001054 TOWOLDMONOOQ2832 irvr operating askerel transformers - tik< every precaution to guwd flit askarel insulation from exposure to high humidity and moistura contamination. Keep S or B pllon drums of askaral dry; lay ttorad drums on their sides with the bung at tha hijpiast point from .floor to keep water off the drum head (which can be sucked into tha askaral by tha drum "breathing"). This precaution is not necessary when drums ere stored indoors, which is tha preferred place for storage. To avoid leakage the drums used for askaral are of heavy construction. Sixteen gauge metal is used, with special rim seal and bung construction. The drums should be drained as completely at possible and then flushed twice with kerosene type solvent to remove all of the askaral. Accumulated liquids and washings should be collected and should be incinerated at hi^i temperatures, e.g., about 2000?, to destroy tha polychlorinated biphenyls (PCBt). Sat Section A. VIII. Tank cars usad to transport asksrelt art in axdusiva 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 whan tha car returns tha nitrogen can be replaced with dry air before any one may enter the car. If the car is to be unloaded 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 extrema low temperature conditions. Convenient handling and pumping temperatures are given in Table III. B. Use Ordinary Personal Precautions: Transformer askarel has been made, handled, end used for over 40 years. It can be handled safely with recommended precautions. If accidentally spilled on hands, no serious skin irritation will occur. However, liquid eskarel has a solvent ection (similer to paint Table III Handling d Pumping Temperaturaa Product Unloading, Handling and Pumping TamperaturvC Pyranol A13B38-3 Inerteen 70-30 Insrteen 100-42 20-55 20-55 35-75 thinner) on tha fats and oils of tha dcin and prolonged contact may lead to drying and chapping of the skin. In case of contact, wadi tha skin with soap and water; remove end dry clean saturated clothing. Clean up spills with rags, sawdust and absorbent day. Eye contact may result in painful irritation but no permanent damage to tissues. If askarel gats in tha ayes, flush with large amounts of water. At with all aye first aid, refer to a physician. To relieve irritation, physicians have usad an opthalmie anesthetic solution es well as opthalmie cortisone acetate solution, or castor oil. - Infrequent exposure to askaral vapors will not causa ill tffeett. However, prolonged exposure to hijpi vapor concentrations should be (voided. If hot eskerel muat bthandled in e doted or confined area, provide tha area with mechanical exheust ventilation -- or I n (ib*N qQVQS TOWOLDMONOOQ2833 <*Sii-J-r - wear an organic cartridge respirator approved by the U.S. Bureau of Minas. `C. Precautions On Opening an Askarel Trantformarr ' Aekaralt of various compositional types are uied. Under arcing condition* the gaiei produced. While consisting of predominantly non-combustible hydrogen chloride, can yield varying amounts of combustible gases depending upon the asfcare! type. Insulation systems incorporating these eskarels and celiuiosie or other organic materials may. when arced, product gaseous mixtures which are moderately flammable. As a precaution, such gases should be removed from the eakerel by bubbling dry nitrogen through the askarel and flushing the gas space 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. Askere! in Equip ment". This guide it published by the Institute of Electrical & Elec tronics Engineers, Inc., 345 East 47th Street. New York, New York 10017. We recommend that users of eskarel transformers refer to this IEEE document. VIII. Avoid Environmental Pollution Transformer eskarels contain polychlorinated biphenyls (PCBsl which have been used in the United States and elsewhere over the pest 40 years for many industrial and consumer applications. During the past several years evidence has accumulated to indicate that PCBs are widely dispersed throughout the environment end that they can have adverse ecological and toxicological effects. * The United States Government's Interdepartmental Task Force on PCBs, Com-72-10419, in their March 20, 1972 report titled, Tolyehlorineted Biphenyls end die Environment", recommended restricting PCBs to use in capacitors end transformers. This report it distributed by the National Technical Information Service, U.S. Department of Commerce. Springfield, Virginia 22151. A document titled. "Guidelines for HendUng end Dispose! of Cepecitor end Trensformer Grede Askarelt, Containing Polychlorinated Biphenyls", has been prepared and is available from the American National Standards Institute, Committee Cl 07, 1430 Broadway. New York. New York 10018. The scope, objectives and tht composition of this committee are: ANSI Committee C107 Scope: Procedures end guides for safe use, maintenance and disposal of eAarel and askarel-soaked materials used in electrical equipment. Objectives: 1. Source of technical information and advice for Federal. State, local authorities end ell others concerned. 2. Encourage development of suitable disposal facilities and keep all concerned informed. 3. Serve as the advisory group for United States participation in international organizations: CEE. IEC, CIGRE. Composition: Organizations active in or represented by this ANSI committee include: National Electrical Manufacturers Association. Electronic Industries Association, Institute of Electrical and Electronic Engineers, American Society for Testing and Materials: Electric Light and Power Association; Certified Bsliest Manufacturers Association; Environmental Protection Agency; Office of Environmental Affair*; General Services Administration; National i I i I i i * , V. . fcBKN 001056 TOWOLDMONOOQ2834 Bureau 9f Standard; Department of d*e Army; Rural Electrification Administration; Division of Environmental i Research, TVA; American Public Rower Association, Water i Pollution Control Federation; Food and Drug Administration; National Fire Protection Association; Underwriters Laboratories; and several sections of the US. Department of Interior. The following are pertinent excerpts taken from the ANSI Guidelines for askarel transformers: - ' 1. LABELING ASKAREL TRANSFORMERS (Pg. 161 4.221 New Transformers. All new bansformert that contein PCBs then have a lebel of adequate durability, permanently end prominently attached to rhe 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 {PCBs). Care dtould be taken to prevent entry into the environment. In case of malfunction or leaks, consult the instruction manual or the manufacturer. 4.222 In-Service Transformers. The transformer manu facturer should make available suitable labels with a similar warning as shown in 4.221 for use on existing transformers. 2. DISPOSAL OF LIQUID AND SOLID WASTES (Pg. IS) 4.1.6.5.1 General. Oitposat of askarets and askarei-toaked materials should be accomplidied by means in which there is no significant release of askarel to the environment At present, disposal is accomplithed by carefully controlled incineration of liquids and soaked software, and by con trolled landfill burial of apparatus and other hardware from which askarel has been previously drained and washed. Present knowledge indicates that proper incineration must involve a suitable balance between dwell time and temperature in die incineration plus oxygen availability and. finally, suitable scrubbers ID remove die HO that mil be formed: for example. 2-second dwell time at 200CTF and 3% excess oxygen in stack gas, or 1.5-second dwell time at 270CTP and 2% oxygen in stack gas. These facetiae 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. <j .it 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) 4.21.21. Adtarel Conditioning Equipment. The condi tioning unit dtould be located either in the storage tank area or in the main transformer manufacturing area for filling ea'th askarel. . 4.21.22 Puller's Earth. Conditioning of new askaref or recycled askarel requires fuller's earth treatment The spent fuller's earth in cartridges or bags, when replaced, should be allowed fo drain thoroughly over drip pans to remote as much liquid askarel as possible. The cartridge units of stas1 mesh construction should be placed in the "STEEL CON- TAUINA TED Wl TH ASKAREL" container tor diqsosidan. Cloth begs filled with fuller's earth should be pieced in the _- TSCSAP BURNABLE. ASKAREL WASTE" container for . ihspuss'aton. > v,-.r . VC v: r\ oovo*1 TOWOLDMONOOQ2835 4. TEARDOWN OF TRANSFORMERS FOR REPAIR OR SCRAP (Pg. 1 " 4.21.4.1 Dram a// askarel from it* unit either into e ' holding font or rwum or into dm drum labeled "SCRAP -. ASKAREL" for disposition, and than allow sufficient time for an of dm atkarei to drain from the core and coils. 4.2.1.4.2 Remora the core and coil assembly from die transformer. Sufficient absorbent material should be placed on dm Poor to absorb any askarai fluid that still drips from dm transformer. 4.2.1.4J Place all materials in the appropriate salvage containers during dm dismantling for later disposition. ' 4.2.1.4.4 Ml used materials, including rags, sawdust, tape. etc. regardless of quantity, diall be put into the appropriate containers for disposition. 5. TRANSFORMER DISPOSAL (Pg.17) . 4.2.3.6 The ultimata disposal of an eskaral-filled trans former may be accomplished in either of two ways' (t) Complete drainage and diamonding with the proper disposal of the eskaret and askarel-toaked components as described in 4.1.6. (2! Disposition of atkarei transformers by meant of junk or scrap dealer*. This dtould be avoided unless a transformer is first drained, followed by soaking the interior with a suitable solvent Accumulated liquids and wad)ings are to be disposed of at described in 4.1.6 IX. Expactad Sarvica Life - Manufacturers indicate that properly designed and installed atkarei transformers are expactad to give trouble-free service for at least 30 years. Since their introduction in 1932, the manufacturers report finding the overall failure rata to be less than 0.5% for all units under test and service conditions. The Edison Electric Institute's report (19S6-I95S) on their member utilities publishes the failure rate for atkarei transformers at 0.13 per hundred banks per year. Mr. Frank M. Clark. who invented transformer askarets at the Central Electric Company in the early 1930s. made the highly pertinent comment based on his many years of experience with G.E. Pyranol (askarel type) transformers that - "The important thing is to keep them dry - otherwise leave them alone". These words of wisdom became especially applicable in more recent years when welding shut rather than gasketing became the mam method of sealing askarel transformers. These units ere sold with the understanding that the liquid is in a normally hermetically closed system. X. Qantral Characteristics of Transformer Askarel Fluid Appreciation of tha following characteristics, as given in the IEEE Guide, leads to understanding the reasons for selecting dielectric breakdown voltage and moisture as the prime practical tests to judge the quality of transformer askarel fluid. Also, due to these characteristics the power factor of transformer askarel will be normally much higher than the corresponding values for mineral oil. In comparison to mineral insulating oil, askarel is a relatively polar material; I.*., Its molecules are dipoles, free to rotate around their axes and responaiva to orientation by elaetrica! forces. Askarel also exhibits a much higher dielectric constant and capacitanca than insuleting oil, and these differences must be kept in mind when interpreting electrical test data. . ................ ... ` -"A Because it is relatively pdsr.aad pnwisarMfth soHency power, askarel b much more electrically sensitive than mineral oil to traces of extraneous soluble polar materials, and^ consequently die choice of ........... ... GBRN 001058 i i ! i i TOWOLDMONOOQ2836 -* constructional mireriais destined for uw in a*irl it very critical. Tbit sensitivity ii reflected in tha power (actor and resistivity ((pacific resistance)of theaskarel. . . .. It it important to note that, with the exception of water, tha dielectric breakdown voltage of edtarel it not generally adversely affected by many of the soluble polar material to which its power factor and resistivity (specific resistance) are to sensitive. In fact, the dielectric breakdown voltage of askarel it somewhat greater then that of insulating oil. Therefore, the values assigned these dielectric fluids in newly supplied transformers ere 30 KV min. and 26 KV min, respectively. I As with insulating oil. askaral must ba kept dry. It can pick up moisture from exposure to humid atmosphere. Under similar conditions of i'i exposure, eskarel can pick up nearly twice as much moisture when measured on a parts per million weight basis. XI. Sampling Transformer Askaral Fluid The following precautions about sampling art quoted from tha IEEE i Guide. ,* "Representative samples, whether of the complete contents or only parts thereof, are extremely important from tha standpoint of evaluation 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 tha procedures and precautions outlined in tha latest revision of ASTM 0 923 (Sampling Electrical Insulating Liquids) be followed. "Because of the high specific gravity (relative density) of askarel (greater than 1), water and some other impurities era rr -.t likely to be found at or near the surface. The top sample, therefore,.onsidered to represent the worst condition." XI (. Evaluation of Askarel Received in New Equipment Some users of eskarel equipment find it desirable to make "es received tests'* on all equipment. It is quite common to use the dielectric breakdown voltage test and visual appearanct 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 extrema car* must ba exercised in order to obtain a representative sample. ASTM Method D 923 should be followed. .. - New equipment with eskarel exhibiting the following characteristics is considered acceptable: - Dielectric Breakdown Voltage Color Condition - Visual ' Water Content Power Factor at 25' C ' 30 KV min. 300 max. (Straw color) Clear 35 ppm max. ASTM Methods 0 877 0 2129 O 1702 0 1533 D 924.D 150 'The power factor of askarel taken from new transformers, reactors and accessory equipment can reflect the presenoe of moisture, dissolved polar compounds, or other contaminants and may vary with the type of equipment from which the temple was taken due to the different ratioe of liquid-to-tolid insulation and to the high solvency power of the askarel. Given an acceptable i weter content end dielectric breakdown voltage of the eskarel as indicated above, a hi0i power factor seldom impairs the serviceWsillty of the askarel within rather broad limits and ii -W * W . n . GBRN 001059 TOWOLDMONOOQ2837 I o c. i, ' tntfteativt of tht *7" txtrinioui tolubit polar mttentti ;`(r-V--- V. ' jr.VV" ' %. ... . . . . ' . ' . . ., t'.. ' . '' _ Recognizing die possibility cd a widl range of power factors being recorded for askarel in new equipment, it it difficult to establish a tingle limit which would be acceptable to both supplier! and users for all applications. However, m a broad guide, power factors up to about 10% at 25*Cand 80 cycles per sacond (hertz) do not in general indicate any abnormal contamination providing that the other criteria (water content, dielectric breakdown voltage, etc.) ere met. Much higher power factors may indicate excessive contamination or the misapplication of tht solid materials used m manufacture in contact with the askaret end should be investigated. 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 voltaga can also bt lowared by severe arcing, askarel turns noticeably blade or has partidat of sooty carbon floating in it if arcing has occurred. Then die transformer should be repaired and the askarel replaced. If the dielectric breakdown voltage is checked periodically and decreases significantly -- this indicates moisture pick-up, arcing, or both. Whan the dielectric breakdown voltage has dropped to 26 KV or less, in analysis for water is necessary. If water is found in excess of 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 operating temperature. If the moisture content it found to be in a satisfactory range end the dielectric breakdown voltage is low, the transformer manufacturer should be consulted. Table IV shows the relationship of dielaetric breakdown voltage vs. moisture and Table V indicates the approximate water solubility limits in askarel and mineral oil. f g i *i I Table IV .. Relation of Dielectric Breakdown Voltage to Amount of Diwolvad . . Water in Aduinl and Mineral Oil Content (PPM) Breakdown Voltage (ASTM D877I Askarel Mineral Oil 0 20 40 60 80 110 f 70 KV 55 47 40 38 10 50 ICV 39 30 26 22 5 i : :HsK.5- GBRN 0010O0 TOWOLDMONOOQ2838 ~ -- -V '. T*)e V V .* '* Appraumats Solubility of Wstar bTibilofwr ' Askarel aid Minwd Oil. _ . - "V Amount of Wstar [PPM) Dissolved ' 3L v : >'' Ji c~- t`o; Askarel _ -- Mineral Ol 1 * ** . ~ -30 -20 22 _ 4 . .. ..rt: 19 -.Jv .. : TO -- ' 10 0 10 20 30 14 . 32 SO 68 86 28 41 65 64 128 . . .3t03 - 33 ' - 58 86 * 40 104 170 - 130 i- ' ;' XIV. Turbidity ... may b the visual sign of undinolwd water, or may indieata dirt. 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 aero. To redissolve it requires heating to 150-200*F and agitation. High d.electric breakdown voltage will quickly indicate that any turbidity present is not moisture; that the insulating efficiency of the askaret is still excellent. However, if the dielectric strength it below 26 KV. moisture should be determined, using the Kart Fischer method (ASTM D1533-601. ' ii- *. The dielectric breakdown toltaga tea for etkerel ear^s primarily as an indicator for moietura. It * by far the moat important ma'mwnanea teat for transformer atkarel. '' XV. Chock Points for Maintaining Atkarel Insulation . A. General Considerations: - Modern askarel transformers with welded construction or silicons or Viton* gaskets (hend hole-cover, switdi and terminal compartment covers) and with properly constructed bushings require little maintenance. With properly constructed trans formers, annual or semi-annual visual inspection and dielectric breakdown voltage test of the askarel fluid dtould suffice for routine maintenance checking over many years of service. . However, many askarel units were installed in the' aerty 1933s : '' before the developmem of some of the better modem gasketing i materials and before improved designs ware developed tor aeaiing I out moisture. Such early units should be, and can be, modernized. 1 Leaky or deteriorated gaskets should be replaced, if the askarel . has become contaminated, it should be reconditioned. At the same time, a general dean-up of the unit and possible refinishing may be desirable. . . If it is not convenient to taka an old transformer out of service for general repairs, leaky gaskets can ba sealed temporarily by painting over the leaky area with epoxy cement. ' . . A survey of users indicates a good number of early-built adtarei transformers (ovar 20 years old) era kept in continuous ssrviea in critical installations by tha following steps (instead of modernization). * ... * V* ....... . .... . . . 1*. * . iv* . . . The operating units are equipped with compound pressure gauges far reading pressure above and below atmospheric Positive Trademark el E. LO^cnt PaNsmoies* Ceneeay.tac; ! U\ V ; " V fl GBRN 001061 TOWOLDMONOOQ2839 t. pressure it maintained on the shell by inuodueing nitrogen at 2 to .. 'jr 3 poundi above atmospheric. Regular workman in the area daily . . record the temperature and pretaure. If a sudden presture drop it r ' '. v.! noted more nitrogen it introduced and the gaskets are cheeked for leaks with soap solution. Leaks are sealed by applying epoxy B. Modern Sealing Procedures: Transformer purdiasert should specify the following modern techniques for sealing: 1. Welding Construction: Covers, radiator connections, switdi and tarminal housings, instrument connections, etc. should 2. Bushing Connections: A number of bushings have 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 waltl 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 teal at tha cap and flange made by being rolled into grooves in the porcelain over silicone rubber rinp. The seal between the cap and stud is made by welding. c. Porcelain or glass bushings with maul to glass or metal to porcelain seals. 21 Boltad 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 % inch thick. Budtings with recessed grooves are suitable to use with cork, cork-nitrile rubber combinations or nitrile rubber at well at-gasket materials tueh as silicone or Viton. 3. Small Size Connections: When not possible to weld, small size connection seals should be made with Flexitallie* stainless steel rings. The surfaces mutt be machined and parallel. The filler between the steel laminations of the Flexitallie ring should be either silicone or Viton. 4. Gedicts for Hand-Hole Covers: Modem 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 by welding concentric steel strips to the flange or the cover. Generally the gaskets should be S/16 to 1/2 in. thidc for covers, depending on the depth of the groove or stop. A rectangular cross-section is usually used. The silicone material should be Dow Corning No. SO Silastic** or equivalent. This is a low compression set materiel. For best sealing 20-25% compression is recommended, with ample clearance in the groove or stop to allow for this compression. No cement is required. With reasonable eare the gasket is removable without damage and is reuseable. Silastic 50 is slightly swelled by askarel which contributes to the tightness of the seal. It it not deteriorated by askarel fluid ' or vapors. It resists weathering and it is thermally stable and i i ti ;i :I "Trademark of FlexHdnc Gasket Company "Trademark of Don Cermag __ _ i GfiRN 001062 TOWOLDMONOOQ2840 flexibte'm aN operating temperatures. ft an .excellent moittura barrier. tit*;, -w- NOTE: Dow Coming. Midland. NTidugaa wB suppfy lift of' SilaRic SO gasket fabricators to 0 transformer .. manufacturers or gun. Thay wit also himi* technical data. Saa Appendix * Saab. Propartita and. Proeuramanta. . . '. .' The Old* Sealing Arrange"""'*: ' * '- " Tha older type gaskets conaiat of either cork or cork-nitrile rubber comb*nations or straight nitrile rubber. `" ' - . 1. Cork-Nitrile Combinations: Coven for tha main tank, hand-holet, twitch and terminal chambers, relief diaphrama, etc., are held in place by studs welded to the flange or by bolts. The gaskets ere cut with openings and piaead over tha bolts. Often Shellac (Westinghouse Style No. 1150419, or General Electric Company's Glyptel* 1276) it used to cement the cork to the flanges. . The following is recommended for selling with the cork -- nitrile rubber combinations: Uu Armstrong NC-7S7 cork-nitrile material or equivalent. The gasket can be cut from a single sheet or by scarfing stripe of the material. A convenient method for joining strips is to make Keystone Type joint. For this purpose. Westinghouse, i Sharon, Pennsylvania, offers their gasket cutter Style No. 328 I B614G01, (about S15I. The joints - end 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. I After installation and bolting, the outside edge of the gasket should be coated thoroughly with epoxy cement to increeu weather resistance. This epoxy cement is a paste to which a curing catalyst it added immediately before use. Typical era: a. 0. e. d. Epoxy Patch Kit ot-C _ Hysol Corporation, Qltan, New York Scotchcaat** Resin #4 -- . .. Minnesota Mining & Manufacturing Company St. Paul, Minnesota Adhesive A-1 and Activator Type 0" Armstrong Products Company , _ , ... Argonne Road, Warsaw. Indtena . ' Adhesive 9860-1, Synthetics Organic Company.' Cleveland, Ohio, used with activator diethylene triamine (Carbide and Carton Chemical Comperry) -. 2. Straight Nitrile Rubber: When straight nitrile rubber was originally used, invariably tha gadcat was recessed in a groove. This wes to prevent gasket flow and to protea the materiel against excessive compression. Although this type ssel wet not cemented, tha nitrile rubber gasket is net reuMsbie. _ Since grooves or stops have already bean provided for the * nitrile rubber seal, Silaitic SO can be easily substituted and is :li recommended. This conforms with modem practice iji XVI. Periodic Fluid Impaction and Whit Checkpoints Moan .)- On a regular schedule -- at six, nine,or twelvemonth intervals -- make a simple visual inspection of your askeral initiation and run a dielectric i breakdown voltage dtadk. --. .. \rv, ' Trademark ot OenanS Bactrlc Cpmcsnv ' ''Trademark of '" r c T TOWOLDMONOOQ2841 ' A. Visual Impaction: ; .... Adural s a dear, feint-yellow liquid. After longterm use this . ... color may gradually intensify to light brown. The fluid should ^ " 'remain clear and free from turbidity or doudinen. . .... Any color change - such as to a green, rad or blue cart - indicates extraction of impurities (color materials! from the solid insulation. ' If a distinct foreign color pick-up is noted, check tha complete range of electrical characteristics and notify the transformer maker. Blackening of tha askarel may indicate an arcing condition. Other color changes alone are not danger signals since tha dielectric breakdown voltage is not likely to be impaired. B. Dielectric Breakdown Voltaga If the dielectric breakdown voltage has decreased significantly from the last inspection, or if it has gredue'ly decreased below 26 KV range (at 25*CI - RUN A CHECK FOR MOISTURE. Use ASTM 01533 (Karl Fischer Method). Tha dielectric breakdown voltage of askarel it 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-staled askarel transformers have service records of 25 to 30 years on me original askarel. XVII. Inspoction Checklist 1. If askarel is clear - even though darkened to light brown, has no sediment or turbidity, hat dielectric breakdown voltage over 26 KV -- give it the inspection "'OK". 2. If askarel is dear, but has foreign color of blue, green, red ... it is "sxtrading color*' from internal materials. This it 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 and consulting the tran$1ormer maker. However, when sampling the fluid cere should tot taken to avoid getting color into the askarel from paint that may be inside or outside of the sample vehre. 3. If the moisture content isfound tobe above 70 ppmat operating temperature, then sampling should be done at more frequent ' intervals to establish a possibletrend, particularly on outdoor . installations. 4. If askarel is dear, but dielectric breakdown voltage drops to 22 or lower KV, and moisture rises over 60 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 even 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 askard is dark brown to black, if black partides of carbon are seen, and dielectric strength is low... the askarel has been broken down by arcing. It cannot be refined and should be removed and incinerated under proper conditions. (See ANSI Committee Cl07 report on Vm and Ditposai of Adcarat and Adtarat-Soakad ' MinrMl 1430 Broadway, New York. New York 10018. If any of these five simple inspection tests eppeer out of the - ordinary or the relationship between appearance and test values is abnormal, contact your transformer supplier for a complete analyts. .... WhencMr a sample is to be shipped to Monsanto, plane follow the ' directions shown undar: SAMPLING ASKARjj^. \ V--- \ . * * n;GBRN 00106** ' > ; I ; _ - | j ; , ' . : j { ' : ' .j ; ; TOWOLDMONOOQ2842 *7 XVIII. Contaminatien in Transformant . Moisture, particulate matter and arced decomposition product! are known to be torious contaminating influtncat on transformar adcarel. Tha power factor tail normally toad for the detection of contamination in mimrtl oil fillod transformant it of little uu for this purpose in askerel filled transformers, due to the extreme affect of extraneous jt soluble polar materials. This increaw in power factor as illustrated in Table VI has no adverse effect on dielectric breakdown voltage. ! Table VI Effect of Common Insulation Materials on Power Factor and Dielectric Strength (Heat Aged 98 Hours in Adtarel at 100*CJ 1 Material Immersed i None (control) .t Black varnished doth Copper jl Pressboard Manila paper Phenol formaldehyde resins l! Shellac Iron Synthetic rubber Askerel After Exposure Power Feetor, Pstoent *t 60 Dielectric Strength eye., 100*0 aye. 1.0 85.0 15 3.0 1.5 1.6 5.0 5.0 70.0 35 KV 42 40 37 30 41 36 30 30 Similarly, trace contaminants from commonly used construction materials can lower the volume-resistivity of askerel, without affecting its dielectric breakdown voltage. This is shown in Table VII. I Simple Table VII Effect of Common Insulation Materials on Volume Radstivity of Adears! * Volume Resistivity a 10* ohm-cm (at 1CWC., 500 Volts DC., 0.1 "gap) 1. New askerel before hast aging 2,000 2. New askerel after heat aging 96 hours at lOCC 1,900 3. After halt aging with 1 sq. inch specimens of: a. Phenolic resin tap changer material 1,200 b. Paper 750 c. Grad* A prenboard (tan) ' 500 d. Grade A pressboard (gray) 500 a. Grade A pressboard. laminated strip 400 f. Cotton wrapping 300 g.Glyptal 1276 cement, cured 48 hr*. at 110"C 100 .1: While trace contamination sadly lowers volume resistivity from high levels, it is important to note that heavy contamination (as whan areid) I': does not lower tha resistivity below the order of 10* ohm-cm. at 10CTC. Tha different behavior of aakaral vs. mineral oil in thaw respects can be summarized ss follows: - High power factor and low volume resistivity in transformer mineral oils are commonly regarded as "danger signals" that the . oil has deteriorated and broken down chemically or excesdv* - moisture is present. . . ,, , This is NOT TRUE of askerel liquid insulation unlew die dielectric ' ;.breakdown voltage b low or the moisture conrent is M0L -. . . . GBRN 001065 * TOWOLDMONOOQ2843 Manufacturers of eskirel typebansforinare point out that it it quia well known that eskaraf transformers with totiaf powtr factor of the adcarel fluid in excess of 50% at room tamparaturt and 60 Hr art gmrg satisfactory service lift. Howttor, there naodt to ha assurance that both dielectric breakdown voltage and moisture are at satisfactory levels and do not show advara trends.. - ..... ~ XIX. ASTM 032SS Mtfhod For InvMtigating The Compat ibility of Treniformor Insulation and Construction Materials biAdcarals -* ' - This method uses the dtangs of electrical and/or chemical eharacteristici of transfortnor askarel resulting from its controlled ' exposure to insulation and construction materials, in order to evaluate . their immediate major ''contamination'* affact on the askarel fluid. Oelayed or long time contamination effects may not be detected. The method also utilises various physical tests on the insulation arid construction materials after controlled exposure to the askarel to determine tha compatibility of that* materials with transformer askarel. Properly proportioned speeimene of the insulation or structural materials art immarsad in refined askarel for f 68 hours at 100 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 tha 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 lava! of 0.05 max. at 100% and 00 Hx and 0.01 max. at 25% and 60 Hx. Corresponding values of tho askarel fluid after heating 168 hours at 100% in absenca of a test speciman art 0.075 and 0.02 respectively. Tha maximum dissipation factor lewis suggested for tha askarel after heating in presence of the tact specimen are 0.20 at 100% and 60 Hx and 0.04 at 2S*C and 60 Hx. .. . . XX Refining Askarel far Rauw : ' A. Filtering Through Dry Blotter Paper to Remow 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 plat* ' . prats are available from Cart Schleicher and Schuell Company, ' ' Keane, New Hampshire and mwtufactwrers of filter presses listed *= .'...... . The filter paper must be dried Immediately before use. For best .' -. results, spread the paper for maximum surface exposure in s hot ' air circulating oven and heat It for 4 to 8 hours it 110%. **-. / r\.\ -. .. . ** " * Circulate the askarel hot (but not over 40%) through the filter ' fitted with the dry paper linore. After filtration tha dielectric breakdown voltage of the eskarel rfiould be 36 KV minimum. PRECAUTIONS: . 1. Filtering should not be dene when the relative humidity exceeds 75%. : 2. Any flexible hows and gaskets on tha refining equipment should be lined with or made of materials that will not . bo softened by contact with askarel fluid. (Materiel! lined with Silicone, Vlton dr Teflon* or flexible metal materials are suRatfe}*. . i .1 I i t ! i \ l ^TredMmWof LJL OuPent OeWewwjpJS GBRN 001066, TOWOLDMONOOQ2844 *: ** V :t *i V* I >.*<1 i 1! Mi B. Disposal of Solid Wsrtai: ' The ANSI guide C107.1-1974, Section 4.1.8 givae detailed recommendations. . C. Solid Inflation Requiring Drying: ` ' " H the solid insulation of tha transformer requires drying, consult tha transformar manufacturer or an apparatus sarviea #>op. a* in - such eaaa ovan drying is prafarrad. 0. Earth Treatment for Maximum Improvement of Power Factor and Volume Resistivity: Wa question whether pumping and filtering tha fluid solely to achieve a change in power factor or volume resistivity alone it justified in today's ecological climate regarding PCBs. We recom mend that in theta situations tha original transformer manufac turer be contacted. 1. Procedure: The askarel liquid drould be relatively dry prior to tha following earth filtration. -. .* V ' Aa a costing on tha filter paper surface use finely divided - Artapulgut* day or Puller's earth dried and activated by heating for 12 hgura at 300-35CTF immediately prior to use. - The ambuftfdt earth liked should be 0.1 to 0.2 percent by wl0tt on die weitfit of the askarel to be treated. Askars! wei^n about 12.5 pounds per gallon. ' To deposit the earth evenly, stir one-third of the earth with a - small portion of askarel in a dean container. Pump the . ' mixture throutfi tha filtar and follow witfi two more one-third portions. Than circulate askarel taken from near the top of tha transformar, pasa it warm (not ovar 55*CI throu^t tha aarth-coatad filtar and feed back throu^t tha bottom transformer outlet Continue circulstion until tha fluid is dear and test show* that tha eleetrieal properties are - fully restored. .' . 2. Effect of Earth on Removal of Scavengers Only di(ft and insiyiifieant loss by selective absorption of tin tatraphenyl and epoxides occurs whan askart! it refined by trsatment with 0.1 ta 0.2 percent by weight of earth. To remove significant amounts of Ota scavenger! requires repe titious treatment with much larger amounts of earth. < TOWOLDMONOOQ2845 V-: v ' - " V. r-- :> rti Approximate Relationship Showing tha Insignificant |*L:` Effect of Power Factor and Voluma-Rawjthrity on ^Z' Dielectric Breakdown Voltage of Tranaformar Adard yew aw VolurtM Resistivfty * x 10* ohm-cm (at Breakdown 100V. 600 Volta Voltage OC. 0.1** oeo) ZS'C.O.V'oep - 68% 7 ' 15% 20-26% . 40-60% . 0.05% . 0.1* 0.7* 20% -- . 1500 600 100 60-70 26 35 KV 35 35 35 35 XXI. Cleaning Arcad Transformer* ' If a unit hat arcad to that tha askare! it no longer fit for titc, a thorough cleaning of tha unit it neeemary before refilling with new askerei insulation and returning It to mrviee*. Follow this procedure insuring care it taken to prevent any Ion of liquid atkarai to affluent streams. A. Drain out all dark, carbon-contaminated askartl. Arrange to have .' tha scrap fluid incinerated under proper conditions. (See ANSI ' Committee C107 report.) . *B. ^ Carefully brush carbon deposits from internal parts and insulation. - using a soft bristle brudi making sura that insulation is not damaged.. . ., - C Flush thoroughly using new' a&arel -- not an oil, not a cleaning . D. Flush a second time with fresh atkarai: drain; then fill to the proper level with new atkarai. --- - . E.. Energize transformer to warm the fluid for 24 to 48 hours; then ,v '.' _ circulate the atkarai throu^t a filter, returning it to the unit . filtered and ready for use. XXII. Sampling Atkarai ' .. .Take a sample at dose to the top of the liquid surface at possible. Merry . large askarel transformers have a built-in sampling tube near the surface for convenient sampling. Than, to make sure that your sample truly represents your atkarai insulation, take another sample from the bottom. If additional sampling tube connections art contrived on the ..Valves for eetier sampling, make the tubes of dean glass, stainless steel, duminum or tin for rigid types; and silicone, or Viton or Teflon tubing for flexible types. . -J-fgz+ESt Use NEWT containers for tha askartl sample. A new and thoroughly .pro-dried, small-mouth quart glass bottle fined with a Bakelite** screw cap with aluminum or tin cap liner is recommended for quick, on-site tasting. (If complete analysis is to be made, a 5-pint size sample is required} '` ' ` r' ; ... Ba xjrt that tha new bottle does not stand open to collect dust or .7. . . ' 7 moisture. Rinse the sample bottle and cap lining two er three times - with adcarsl from tha transformer, then fill it. If the sample will be -- ------- ---------- - --------------- *--- -an be used. If sample is to be i bottle or wrap dear glass with insulation on a warm, moist day TOWOLDMONOOQ2846 ,,_ , . *" , - t. Make turn that the asfcarel it at least as warm as the unrounding ' - 'air. (Cold liouidt can rendsnsc moisture from humid airJ . . . C. When nmpfing mfcarai from trenetomwn, R Is boat to taka the . sample whan tha unit ia warm and operating at avaraga or . maximum toad, especially for a cheek on moiatura at raflaetad try '' a diclactrie breakdown voltaga tart. Sampling tha warm taker* - - more miy rapraaanti its condition during oparation. . - ' . Experience thaws that wttar wRt migratt from a transformer's ' solid insulation to tha adural liquid and vies varsa, depandingon . tamperaturc, Tharafora, whan tha transformar is hot, tha moistura \ ' is moat likaly to ba found in tha liquid. This accounts lergriy for pariodic variationa in dialactrie braafcdown voltagi. For exempli, a relatively high dialactrie breakdown voltaga may ba found during winter months and a ralativaly low dialactrie breakdown voltaga during tha summer months on samples taken from tha same unit. Whan tasting has bean complated, tha remainder of tha fluid sample should ba destroyed by high temperature incineration deserted in Section VIII. \ 4 4 4 \ TOWOLDMONOQ02847 Askarel Filled Switches and Terminal Chambers 0 . I. Introduction High voltage Itads art uiuatly correctad to askarel or mineral oil-filled network transformers and power centers through terminal chambers and switches. In some cases terminal chambers are not used, and the high voltage leads ara 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. Askerel transformers with attached switches have been in use for about 30 years. Whan they ware first introduced, the availability of insulating and gasketing materials was rather limited and even the bast materials st the time had no service history. At a result, inadequate gasketing materials such as cork, nitrile rubber, and nitrile rubber-end-cork particles were used. While satisfactory for a limited period of time, these materials cannot be depended upon for the expected long lift of the equipment. ' The terminal chamber is usually above or below the switch compartment end separated by e steal 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 saep into the askarel. Whan the terminal chamber is below the ewitch. askarel can drain into the terminal chamber. II. Sources of Contamination There are three possible sources of contamination for askarel in ewitches end terminal chambers; they rank in this order of frequency: (11 water entering through poor gaskats; (2) decomposition products from arcing when switch is used to break magnetizing current; 13) entrance of pothead or cable compounds through leaky bushing teals. -. ' ' ' ' Unlike an askarel transformer where the amount of contaminant is likely to be vary small (probably only trace amounts) in relation to the volume of askerel fluid -- in switches or terminal chambers with faulty ` wait, the amount of contamination can be relatively large. .-/ - ' ' ' j. . ' . - ' ' *':i ' - . ' - Experience has dtown that, based on the number of installed eskarel-fwiteh units, the percentage of failures is extremely small. Whan investigated, it has bean found that most failures originate in the switch timber. Water is tha chief aource of contamination. However, heavy contamination of askarel with petrolatum end asphalt material, due to leakage, have caused few failures. .' Petrolatum Is used frequently for filling terminal chambers. Whan either .. ' ... cable oil or petrolatum seeps into askarel, no great harm results. The . : ' fire resistance will be somewhat decreased and power factor of the - _... askarel will increase with an accompanying drop in resistivity. While ... ./` `T-'" highly undesirable, it is doubtful tftat failure of tha unit results. Where ' ''. .. asphaltic compounds are used in glace of petrolatum, the dangtr it .' .. ...:. increased somewhat became asphaltic contamination may cause .excessively high dielectric losses in tha askarel. Whan die terminal chamber it below the ewitch chamber, tha potting compound can be contaminated by artare! if the bushing seals art leaky. This it undesirable because the askerel will increase the power factor and conductivity of the potting compound or cable oil and develop heat from dielectric iota, if this mixture it drawn into tha cable V- ' - if- GBRN 001070 / K i I I i | i I t j i TOWOLDMONOOQ2848 r-srer insulation,'* csWefaHur* Is Ukafy. Thw agio* emphaeias the '.' importance of tight bulling etMmbliaL, -C^KTjwti: >;'*j- -;; . III. Sealing Switches and terminal Chanter* Proper bushing construction, mm of Silastic suit and welding wherever. possible it highly desirable (as covered in Section A!. Where at elastomeric seal is to be used fat contact with both adcarel and petroleum oil, DuPont's Vitan is suggested. ; . For new equipment the user dtotid specify these modern seeling arrangements to keep out contaminants and minimize maintenance. IV. Askaral Used Under Mild Arcing Condition* The IEEE Guide for Transformer Askerel ceils attention to the following: "Askerel is ussd, to torn* extent, in spperttus where it is subjected to light intermittent arcing, such as in self-contained induction regulators, whirs operating switches art continually producing slight act, in trsnsformsr de-energizing switches, etc.. Under normel conditions, deterioration of the cskeral is wry slight. However, improperly adjusted or dtfectiw switches in this type of apparatus can produce excessive end prolonged arcing and accelerated deterioration of the askerel. It is recommended that when askerel is used under these conditions, checks of the liquid, especially for moisture end dielectric breakdown voltage made more frequently than when it is used only a a cooling and insulating fluid. Deterioration of this type it indicattd 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 eppropriete concentration." V. Maintenance for Askaral Filial Switch* A. Switches used for grounding after power source hat been de-energized will net 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. At t general rule, the liquid should be checked after S to 10 operations. 1. On newly insulted switches, check the askaral 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. Cheek edcerel for: ' - a. Dielectric breakdown voltage (ASTM D877); It should ' .. be 26 KV minimum. If dielectric briskdown voltage is . ' low, confirm presence of water by Karl Fischer method ASTM D-1533. Filter to remow moisture. Dielectric ' V.^V ' strength should then be 30 KV minimum. - . b. Presence of carbon from arcing; Fluid should bo relatively free of cybon. If badly arced and wry Mack, replace fluid. If only minute amounts of carbon era present, filtration is recommended. Cheek power factor of liquid (should not be over 5% et 2SK end 60 eyelet). - - . - . Flush out switch dtambsr with Mwral gallons of fresh ... .: * ' eskard before refilling. '' ' '' X If there is discoloration, high power factor, detectable change in specific gravity or refractive index, or if fluid flashes below 2S(PF. there it a possibility of seepage of potting compound - ' into the switch compartment. In this case, correct any leaky " - bushing Melt with proper replacements and fill with new . ' askaral. ' 4. If terminal chamber Is below switch, check potting . . compound for pretence of adcarel (can usually be detected . . by odor or by an increese in specific gravity). If adcarel la . present, correct any leaky butiting Milt with proper ~ - . replacements, and renew compounds - '. ; ". .V ' ; -- 8. Examine cover gaskets visually. Deterioration can be detected . - C i i TV ' ' . TOWOLDMONOOQ2849 0 _____- -.V >.. - rr. ' W swelling end cradling of the exposed edge. In cam of . aavere deterioration, liquid laap^t b uwady present. __ 1 Check for leakage at padcing gland of switching shaft. If -- Waking, rapaok with aSilasticring typo gadcat. Bel.?';?* * v. * . . "I'Zxr ' Vt. Aikird Under Excessive Tamporaturt or Fault Conditions Tha IEEE Guida also points out that, "Chlorobenzenes uMd In trantformar askaralt bagin to boil at tamparaturas of about 205%, under atmospheric conditions. If tha matarial it haatad to such high tamparatura in a mltd systtm, pratsura davalops. Pressure will also develop in the system if the askarel it arced sufficiently to generate copious hydrogen chloride "Therefore, it it recommended that wherever possible, sealed askaret-fillad equipment be provided with pressure relief devices. These devices must be large enoudt to provide immediate relief at e definite pressure, and to prevent further build up of pressure if decomposition continues. It must be remembered that the pretence of devices of this tort does not necessarily preclude the rupturing of containing vosuls, tinea pratsura build up can be extremely rapid under violent arcing conditions." 0 (C Toxicity& Safe Handling I. Inhalation At ordinary temperatures the chlorinated biphenyls in Askarel have not presented industrial toxicological problems. The hazard of potential toxic exposure varies with their volatility: die lower-chlorinatsd, morevolatile ones present more of a potential problem from the standpoint of both inhalation and skin contact. Whan Askarel fluids are used at elevated temperatures, engineering controls mutt be applied, either by the use of dosed systems or by effective local-exhaust ventilation .together with general workroom exhaust. Vapors of Atksrel at room tamparatura diouid not be breathed in a confined space, and no vapor of any fluid evolved tt elevated temperatures should be allowed to be dispersed into the general / workroom. '^ .. . V . - Inhalation tests on animals indicate that the maximum safe concentre ; tlon of vapor is in the range of from 05 to 1.0 milligram per cubic meter of air. The threshold limit value (maximum sitowsbis eoncen(ration of an 8-hour working day) set try the American Conference ` of Government Hygienists are 1.0 milligram of tfte lower-chlorinated biphenyl compounds par cubic meter of air and 0.5 milligram of the more-hi^tiy-chlorinated compounds, per cubic meter of air. II. Skin Contact Prolonged or repeated akin contact with tha Askarel fluids must be avoided by the use of doves and protactivt garments, because of the possible occurrence of a condition called ehloracne. Althou/i reports of this condition caused by Askarel are rere, it can be produced by excessive skin contact. If tha fluid It spilled on the skin the skin should be wished inthe usual manner with a soap solution. A burn ceuad by contact with hot Askarel dtould be treated like any ordinary bum. '. U. .For dhpoal Instructions of Adtaral fluids, see Section A VIII, pegs 8. i->-> - - VT~ is3&?-*V .. W. `J. . GBRN 001012 i i i TOWOLDMONOOQ2850 ^Analytical if fSEi*-*- '-`tr3&* jonTransformer Askarel Available From Monsanto -i -*J<JvJL-V5iKT?ftirlA*2S . . . Transformer inert not wMting tff'meka tfiafr own fluid entlym etn obtain the sarviea from Monsanto. Smply contact Monsanto ; and qsecify what analyst* art wanted. You wifll bi tant do propeMizod, clean tempt* container, fitted with a proper label. Wh*n you racaiv* tfiis, carefully taka your sample (following dw prooadura for sampling in this gride). Send the container to Monsanto's laboratory. OtargH listed Include tempi* container and laboratory coats. The diargat are tito* in effect March 1, . 1975. and are subject to changa. ' i.;`y . Types of Analyses Availabia - Analysis I) . ROUTINE MAINTENANCE CHECK:w. J'; : Total Charge: S304JO '' To detarmina the general condition of th* fluid and find whelhar furdiar anafyds it nacastary. (one-quart sample required) Properties Tasted - . - Dielectric Breakdown Voltegt . Color and Condition ' i Moisture . . You will ba notified of the results of this test. If further testing it indicated, and you want a complete enelyiii, you will be *nt a 1 _ five-pint tampla contain*. This sample will ba used for die following aariet of tans: Analysis 21 COMPLETE ANALYSIS . . ! Total Charga: S7S.00 '. (1) To determine the extant of fluid contamination. (2) earth rafinamant to determine what degree of restoration of electrical and insulating properties it possible, <31 cheek test SO tee how the fluid responded to earflt treatment. ' a) Complete Analysis: to dttermine the extant of contamination Properties Tested .. . Free Chlorides . . Color end Condition ' . Acidity ' :' Specific Gravity ' . Olelactrie Breakdown Voltage * . " Refractive Index : - V". : Power Factor, Dielectric Constant, and Resistivity . _ . . . .. - b) Earth Refinement Response: ^ '' - Cons:sn of treatment for 2.5 hours at 5040%. with 0.1 to 0.2 percent by weight of properly conditioned Attapulgus dry . . and then filtration throupt dry filter paper. . c) Analysis After Laboratory Earth Rafinamant: ' ` ' . .. ' Properties Tested . Acidity * .. Refractive Index. v . ` Dielectric Breakdown Voltage - - . Wat* - r. . ' _ Power Factor, Dielectric Constant, end Resistivity ' Free Chlorides .. You will be notified of the results of this test series on your sample. Then eft* refining your entire transform* fluid fill you ' can check on the results by requesting the following anatywx: _ .... Analysis 3| - . ANALYSIS AFTER EARTH REFINEMENT . Total Qtirgs: S60.00 , .r- jr.r.V>; `{Thts charga will not apply whan anafysm 1 and 2 hav* already been made4 .To determine whettwr the entiri lot of the askarel fin remanded to the seme extent as dte laboratory sample, (fiva-pint sample required) PropertiesTestad '.^rt.............- FreeChlorides . t . ' ^ ,-.-,7..Color and Condition ;-- . Refractive Index - Acidity ....... - r Dielectric Breakdown Voltage ; Bin* . . . *;s` .... ' ' " ' .` , ', Pow* Factor, Oialactrie Constant, and Resistivity * * , , . . To arrange for dw test* described above writeto the following addreee: . . . David Wood . . . . . - .. .'..7. -v '... Monsanto Industrial Chemicals Company.- _ ' . ' ' ' 800 North Lindbergh Bird. ,.'. !*.V .'. *' ' '' SL Louis, Minouri 63166 Semples to be tested dsould be ctorfy marked far Identification end sent directly tot " Company ; /i. W. (I Kmmmrtch Laborewy'.' I r : - - 7- ~ - . - ; \s 4'Vi'SH ^.y' SOuget BUnoii*2301 Vr'fc ' t . ,. . .. . .. ., *' ~'mMMWMUIaiaDInji 001073 TOWOLDMONOOQ2851 < APPENDIX A Askarel Stability and Composition of Arc Formad Gaa: Aakaral insulation it ono of tha moat inart, chemicatly-stable heat ratiitant, non-corrosive liquids known. It will not break down, oxidize or sludge whan exposed to air and high temperatures, 1SCPC. or even somewhat higher. Arcing, however, will break down the compound to liberate tome hydrogen chloride and small amounts of carbon. ' - . - ' . . r-. " APPROXIMATE COMPOSITION ARC-FORMEO GAS FROM TRANSFORMER ASKAREL BLENDS . ASTM TYPES 0 AND G (INERTEEN 70-30 AND PYRANOL A13838-3, RESPECTIVELY} Gas carbon monoxide carbon dioxida oxygen hydrogen chloride (note the absence of phosgene} Amount 0.3% 0.3% 0.8% 13% 97A% This arc-formed gas from ASTM Type D and Type F transformer adcacats it non-flammable and non-combustfblaL ' 0 For all practical purposes, tha amount of gas liberated from askarel under a given sat of arcing conditions it about 100 cubic centimeters per kilowatt second. . .. . APPENDIX B SOLUBILITY OF GAS IN TRANSFORMER ASKAR ELS ASTM TYPES O ANDO - APPENDIX C ... . . , .. .. ' Percent of Get By Volume Corrected to: . - aW 760mm . .... 0"C. 760 mm 2S*C^. ... loot: Carbon dioxida . <-. " * - 71%'riiF 47% Air > . SJ . 43 Nitrogen '" Hydrogen chloride1' ba *v. AM 373 * sos .. . ioo*c ' * . ..* * SJB BA SA 43 - - - --- ' ;1 In absence of scavenger . ' . ' j TOWOLDMONOOQ2852 APPENDIX E .. : /. . - .......... ' THE DENSITY OF INERTEEN 70-30 AND TRANSFORMER FYRANOL A13R3B-3 ' Approx. Density gm/ec. . Temp. *C 0 i. 40 ao ao .. ~ - . : . 'Inerteen 70-30 137* 1362 1329 1307 1.408 ."** - Fyranol A13838-3 * 1377 1356 1332 1310 1.488 APPENDIX F The thermal conductivity wlun of transformer Fyrinol AI3B38-3 at 27*0 and 58*0 an 26.2 and 253 x 10* atones antimeterr1, dagraa cantigradr^, saeond-', respectively. Or, approximstdy OjOS BTU par (hrj (tq. ft.) CF.I par foot. This seme approximation applies to Inertaen 70-30. . APPENDIX 0 ___________ ' '________________________________________________________________ Heat Capacity - .. Over the temperature range of 29 to 126*0 tfw specific heat of transformer askaral is dose to 0.30 calories par gram par degree. - .. . - ... - - APPENDIXH ~____________________________________ Coefficient of Expansion ' /Vt*-//-' . . The average coefficient of expansion of transformer a*are* over the temperature range 20 to 100*C it0.0007 oc/cc^C.One gallon would instate to J.066 gaXona on heating from 20 to 10DC. APPENDIX! Vj rr* Fire Resistance Askaralt of rarioto eompositional types are used. Under arcing conditions die gases produced, while consisting of predominantly non-combustible hydtogtn chloride can yield varying amounts of combustible gases depending upon the adcareltypo. vi-. , Insulation systems Incorporating theta askaralt and callulotic or other organic matarials may, whan arced, produce gaseous mixtures whidt are moderately flammeble. At a precaution, such gates should be removed from the askaral by bubbling dry nitrogen through (he adtaral and flushing the get spaa with dry nitrogen before any work it performed on the apparatus. TOWOLDMONOOQ2853 APPENDIX J Sttlt. Properties and Procurement * Dow Corning Corporation, Midland, Michigan with Districts at Atlanta, Boston, Chicago, Cleveland, Dallas, Los Angeles, New York City, Washington, D.C. and Toronto hat available Bulletin 0BO19, August 1962 entitled 'Silastic Design Data". This lists the gasket fabricators throughout the country from vrftom the `Silastic SO" gasketing can be purchesed in sheet, extrusions or molded shapes. Generally, Silastic 50 sheet goods ere stocked by locel die cutters, hence, could be generally purchesed loeelly. 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 (deer) 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 sheeting or extrusion. Then to obtain the desired physical properties the fabricator must oven cure the Silastic 50 for 24 hours at 480*9. SPECIFICATIONS* ASTM D676 ASTM D412 ASTM D412 ASTM D396 Color Specific Gravity at 77*F Hardness, Shore A. Scale Tensile Strength, psi, min Elongation, percent, min Compression Set after 22 hrt at 300*F, percent, max White 1.20 *0.02 45 to 60 BOO 260 30 `All physical properties measured on 0.075 inch thick temples molded 5 minutes at 24CTF, and oven cured 24 hours at 480*F. APPENDIX K Caution Label J . The following or equivalent caution statements should be fixed on all containers of transformer askarels and the transformers themselves: This product contains Polychlorinated Biphenyls (PCBs). 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 dothing, the dothing should be removed at 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 asksral fluids in 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 dtall be construed at applying to other than askarel insutetion. Data end maintenance suggestions herein do not apply to the ether components of the transformer. All operating and mainteAance suggestions recommended by the manufac'turer of the transformer should also be carefully followed. ^fcecause 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. 6BRN 00107b TOWOLDMONOOQ2854 US CUSTOMER SERVICE CENTOS fe-QMMM-'1: M ^ t-\-_ . ak*okl onto *****~ jp'zT'' wyy **ft. m '. . -. Td. 13101 till -" ATLANTA. OAOAGIA . 3301m -- rJiV.JilSlr* ISA ostom. massachusstts ttitt taoroaS*dm . Tat. miHMt-AATA . . , r- Houston. rtXAS mgr ' ' -* IJBI Mr OR row BtBhS. i! nWsudtmsmuar Amt LOS AHGSLSX CAUFOAFNA lOOIOOWMdOt NMfMlwk, WAmk . IT141 IIHW nsw yoak, nsw toak rceoi 1w11. Imt AsuamrtotosoofaMoo Antrim ST.tLoOoUNIS. U. MndISOSoOr#UASINAS.StSA Tm. m*i tA*-ioee SAN FAANCtACO AAY AASA anoLtOmm Onto Ova, &Mom* 30003 Tot. ttOtl 04*0414 WILMINGTON. OALAWAAA ttttO Sum 204, toncrofl AMf. 301 ISOuardd* Aood TA. (3031 471 MOO INTERNATIONAL OFFICES AAOtNTlNA Monaa** Artandm SJLLC. Aid* M*t*m NBA Floor, in* A It* Auono* Atm. Arfmdm AUSTRALIA - Mw-- .lawn LMdmt tom row. Mm Ora MM 1(1 Flindora Stmt MAbourm. Victor* 3001 ttonaan* Auatral* Umtaod 30 Tatar Saraoo A*tat*. Sad**r. NAFF AuadMN 2030 FomOIfkoAoa tnnC tout* AmaarAN SOSI A a Mi OX Hand** C*i*m Quaondand, Auatrm* 4000 atonmnaa AdOdat* UaHWd . For* F. a Mo 77 flbiAibiRB FtmaAuatral* AOIt ' ' AUSTAIA Monaann OmbH AudoNaNa* 13 ArlOIOOAm I, AALOIUM ' Monmm* fwa*t SJL I.Ftaa - 10301 Mormn* twott NYMA **" -|R - | aaabl MrHMmm**Udo, v-r * v.- CAN tn COLOMAIA Mram Omraro H.NoTr-tl OtNMAAK 4 Aymnmommdo OK !tO*Oc*a**am* BLSALVAOOA MgmmOM AWHoMANm tTAuonWa Suey OHM*M** M Mn SAnter. USataador FINLAND Arkodionk** AC 00 00100 HAmAI 10. FMoad FAAMCA Sec*m Mormom SJL 0 n 4"Aram** 70Far* m Fromm OUATtMALA Mourn** Gm tdONMOm 7aA**Ma hit taMACKr, HONG KONG ****** Fm taaoLat. Ma*afan**t Hama*. Md AMtr Ho*tKo*S.XCC INDIA MOWN CnamkaN 1st. Monaan* Oiamleat *H*tN FalLat IAt Froducml IISAnaAt.loAardOa lotnkor 400000. MAN MOWN CHROMA Lad. It Adandtamo* IMAM ` - TOO OOI. amt* Monaa** OmodaoN (Ml Am Lot HlHNM 310311 Lamit ~oofot. Mind* ChordoaN Lad. . 3/t Aar!At Aood . Mam OoAd noOOI. AWN INOONSSIA A. T. Monaa** Fa* ANodtad* III Of- O' ***** ITALY V*ANkAiomai*MI . M4m* 3013*. I*M sir, mm ka At. MmunmuM 3 mama CMftAa to. Totro. Jatm '>V . <* Far I :> ' -- nawaaaiano i fill 4Ltd. ISOmi ft** Amt Amman AidOkadt.MmZaaMt NICAAAOUA 0Mm***t F.O.Aot i MVrriiff Odol.C ' ANTUFAtNAA ttmmm Ftiitmtm tot. A*l 1101 Aacuritr taut A Tram trot An* An. ANttb ANA O-TOt. FhMmimt FUIATO AKO r An Am. Aomtoum St MoAHdraa.Avar*Aim AINOAAOAt Mortar* 9**a*ort Cbmnr IFmJ Lu Suita fOS Catnrr AMs. T Floor SOUTH AFAICA Monaa** Am* Atrka tFty-l Lot tt* Floor. AanAam Ctty Hd*. ~ ' , riinwb. Sou* AM* ANGOON IXI let AWintALAND Mo**** ISumalSJL <10. ) TAIWAN ****** Mr MR Ltd. (Tafom* trandil 30Chant A* Oaat Aood. At* Flow tact** I, TaimM THAILANO A* Atoor, Kiaantf MM 110 SUom Aood Aa*0t*. ThMNnd UNITAO KINGDOM Mo**** Lad. It-tl VNaorlo Land** OFflH ONQ tntmrd VSNtZVALA tton***(Vamtuoh>CA Tom Mm* At* st I III. I WfST OAAMAMY Monmm Aaaama Monsantoc LouU.Mo.O1i0 . GBRN 00107? TOWOLDMONOOQ2855