Document G5nrO74NDeoJaaQZx1wwyV6nq

BULLETIN NO. IC/FF.^R (Revised iVardi, 1975) ; / i nA*. . . \\ ;i ^ U ij Li ` ^ r'\ ? -a s- > H * . ' _ ,, -/g1. TOWOLDMONOQ40472 SECTION A TRANSFORMER ASKARELS......................................... 1 I. Introduction........................................................ 1 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 Trrmsformer Akrel Fluid........................................................7 XI. Sampling Transformer Askarol Fluid ................8 Xil. 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 D issol ved 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 Procedure s ....................... 11 C. The Older Sealing Arrangements.................12 XVI. Periodic Fluid Inspection and What Checkpoints Mean ..................................12 A. Visual Inspection......................................... 13 B. 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 ol Askarel...........................................................14 XIX, ASTM Method for Investigatingthe Compatibility of Transformer Insulation aixl Construction Materials in Askarels........... 15 XX. Refining Askarel for Re-Use.............................15 A. I- iitcripg '| hrmi'ih Dry Blotter Paper to Remove Moisture and Extraneous Particles.................................... 15 XXI. XXIt. Table VIII - Water Removal by Filtering Askarel Throuqh a Paoer Press . . B. Disposal of Solid Wastes . C. Solid Insulation Reouirina Drvinn D. Earth Treatment for Maximum Improvement of Power Factor and Volume Resistivity ...................... 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 Filled 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..................................... 3) Analysis After Earth Refinement ............ SECTION E APPENDICES .................................................... Appendix A - Askarel Stability and Composition of Arc Formed Gas.................... Appendix B - Solubility of Gas in Transformer Askarels ..................................... Appendix C - Effect of Temperature on Dielectric Breakdown Voltage of Askarel . . . Appendix D -- Comparison of the Approximate Viscosity in Saybolt Universal Seconds of Transformer Askarels and Mineral Oil............ Appendix E - The Density of Inerteen 54201 KA 7336-9 and Transformer Pyranol A12B3B-3.......................................... Appendix F - Thermal Conductivity Values of Transformer Pyranol A1383B-3................. Appendix G - Heat Capacity ........................... Appendix H - Coefficient of Expansion.......... Appendix I -- Fire Resistance........................... Appendix J - Seals, Properties and Procurement ............................................ Appendix K - Caution Label ........................... 22 22 22 22 . o 23 23 23 23 24 24 24 24 25 25 NOTICE: "Nothing contained herein is to be construed as a recommendation to use any product in conflict v.nn any patent. MONSANTO MAKES NO WARRANTIES a; TO THE FIT NESS FOR A PARTICULAR PURPOSE C ' MERCHANTABILITY OF ANY PRODUCT REFERt- ' TO, no guarantee of satisfactory results from reliance u. on contained information or recommendations, and u * claims all liabi itv for any resulting loss or damage." j v < 1 I I i I I i t V 1 1 l 1 I 1 0666604 TOWOLDMONOQ40473 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 in 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-22S3.) Under arc.ng conditions the gases produced, while consisting of predominantly non-conibustible 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 and offers suggestions for sealing and maintaining askarel in old units. By following this guide, we believe users wiil obtain maximum service from askarel insulation with a reasonable minimum of maintenance If questions arise relating .o the designing and building of transform ms, these should be referred to regular transformer suppliers. Monsanto gratefully acknowledges the assistance, guidance and m.j contributions c1 certain lata by the following: Edward L P.aai >-- General Electric Tr. T. K. So3t - V/estinghouse Electric II. History of Trade \iame Types "A$kjr>: ' is the cc-m-rh name for the fire-resistant o-.-ici uiv.ila m-. and ccolant first used i > General Electric `Company in :ZZ?. for nem Fyranol1 brand name fi i-resistant transformers, Westirmr.ou;.* Electric Corporation uses their b and name, Inerteen.2 Whatever the trademarked brand, the askarel contains chlorinated biphenyl -- one of the b ,-st liquid insulations developed by science.' ms inert material is ch mjcolJy stable, fire-resistant, heat staolj, non-corrosive, and has high dielectric strength under the opt-ra mg conditions encountered n transformers. In addition to manufacturing Aroclor (chlorinated biphenvi), Monsanto diso mixes this dielectric fluid with chloicberucnos to produce the presently used Inerteen and Pyranol blends describes' in Table I. ' "NOTE. Materia!* dusi.;)'ated 'fire resistant' generally a>e more difficu t to ignite, or once ignited, burn at a slower rate tnan corresDoncim^ convent oral materials. This term ones ut mjn that fire icsittant mjtwui, wnl not t-jin. However, when pic.-my u.-.'J. Monsanto's foe resistant ASKAHcL rLUIb . .;? useful m helping c us tonic s .ive t me ir fire safety re.iuiryment s." ^Trademark o' urni.rjl iw Company C-y. ,, ^ Qt We'tmof'ou* L Ie-r t< >c Corpora' inn '-HrcnstcMO no fni.it oi Monsanto Company 0686605 TOWOLDMONOQ40474 Table I The Composition of Typical Transformer Askarels Method ASTM D22S3 Type D Type E Type G Trade Names Inerteen 70-30 Inerteen 100-42 Pyranol A13B3B3 Ingredients (% by wt.) Aroclor 1254, chlorinated biphenyl (54% chlorine by weight) 70 Aroclor 1242, chlorinated biphenyl (42% chlorine by weight) . - Trichlorobenzene 30 Phenoxypropene oxide scavenger 0.18 to 0.22 Diepoxide scavenger - 100 _ 0.18 to 0.22 - 60 ., 40 - 0.115 to o.i: ASTM Method D-2283, titled "Chlorinated Aromatic Hydrocarbons (Askarels) For Transformers", also lists the composition of all transformer askarels used at various times since 1932. Monsanto manufactures similar transformer askarel fluids in England where the trade name Pyroclor is ured. III. Interchanoesbility 'In general -all-transformer askarels are interchangeable. However, it is suggested that the transformer manufacturer be consulted prior to mixing in significant proportions o' retd p.'brtin.'ficn. IV. Transformer Askarel Specifications Specifications for the three mor.err. transforms askarri fluids era shown in Table II. V. Ordering Instructions Monsanto's current policy is to s-.-il .:k. ;J transformer fluids only to transformer manufacturers. Otiio.s .rv.orcstc-d in these iiuids .-ic-Lld contact the manufacturers of ask rei transformers and not Mcivtari'.:.. The transformer name plate indicates the transformer maker a:vj usually gives suwicient data to identify the specific askarel fluic; .sod. 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 3skarel water-free will insure long time service. Askarel is heavier than wetter. If water gets into askarel insulation, only a tiny amount u.pproximatvly 12a ppm) dissolves -- the rest floats on top. Askarel is very insoluble in water, only about 200 parts per billion o' askarel dissolve m water, at normal temperatures. VII. Probations Whun Handling Drums, Tank Cars, and When Opening Transiormors Tin- f 'lhv,.') } sri' `ignilii.Mnt precautions: A. Uri'ii ur v l).n mg l l.nutn. In lumdimj, /.or mi). i-i j md in^vating .isk-uel -- m 0686606 t J-'ll Specification Properties1 Cb- APHA ii'-r content ppm (ASTM 01533-60) A, ;CJ W mg KOH'g (ASTM D974-55) D n tnc Strength. ?5 C. 0.1 in. gap ASTM 087749) l) Const ar**, iniyc, 60 Hr t A STM 0924-49)' ' . ,.;m: R.-s.$!wity. 10&C, . buO volts DC 0 1 inch gap, 109 ohm-cm f ASTM D1T69) h brf.jmc thlo'idos, ppm (ASTM 01821 and 6 E. Method E4C41B) R-.ffachvd index, 25'C (ASTM D1807) V.cmMy at 37.8 C (ASTM D88-5G) Sj,holt Univetsul Seconds p.."jr Pomt LC (ASTM D 97 57) s --cif-c gravity 25 15 5^3 (ASTM D1810) Lh.ro ,,o nl (ASTM 092) LA tiiiuPori targe (ASTM D20-56) corrected \ry. st'-rn :i'u1 be'ometrr. pressure Transformer Askarc! Specifications (New Fluid) I - General Electric Co. Transformer Pyrcnol A13B3D-3 ASTM D2283 Type G Westinghouse Transformer . Inerteen 70-30* ASTM D2283 Type D 150 max. Clear ; 30 max: 0.014 max. 35 KV, tnin. 150 max. Clear 30 max. 0.014 max. . 35 KV, min. . 4.2 to 4.6 4.2to4.5 Westinghouse . Transformer Inerteen 100-42* ASTM D2283 Type E 60 max. Clear 35 max. 001 max. 35 KV, min. 4.7 to 4.9 i03 . 0.10 rnax. 1.6110to 1.6120 44 lo 48 38 or lower 1.495 to 1.510 None to boiling 1 1st drop 200C min. 40% max. below 270C 90% 379 vo 394 . TOO 0.10 max. ' 1.615310 1.6173 56 to 61 ; -30 or lower k 1.518to1.528 None to boiling 1st drop 200C min.; 35% below 270C 90% 379 to 394 * r ` 100 . 0.05 max. 1.6240 to 1.6260 82 to 92 -17 or lower 1.381 to 1.392 None to boiling 10% 325C min. 90% 360 max. r .j- Co'^OMon test Color. APHA A< Kilty, mg KOH-'g lno! j<jnic chlorides ppm C'lrHitt'Un Scavenger content Typical Properties2 C'JtMn u'ot of Th-.vni il Expansion iASTM 01903). ctnA'cm?/C . Arc formed g.i^es `Arson~h juse ui>:s th :if private number Inerteen S-'TulKA for Imuteen 70 30 and irieir pnv.n? (..-`r irt.-b n f. 4201 CM for Into, v-:1 lCO-42. ` 1J's;. i .ti J e t: r; a I .Vi'S . t ,i.. 11 m; on1. s rrvl s tesicd m :h l.ibo ; ; , 56.4 f- 0.5% 55.6% min. 43 0.5% After heating 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% Dicpoxidc phenoxypiopene oxide phenoxypropene oxide 0.0007 0.0007 ; 0.00QG8 Aikareb of various compositional types are used. Under arcing conditions the gases produced, while consisting pi fdorr.injntly of non-combustible hydrogen chloride, can include varying amounts of combustible gases depending upon the j-.k.trel type. Insulation systems incorporating these askarels and ccUulosic or other organic materials may. ,.t"'i. un;:J. produi.e g.'seous mixtures which are moderately flammable. As a precaution, such gases should l uiii/. /'J from the ask.ucl bv bubbling dry nitrogen through the askarel and Mushing the gas space with dry nitrogen ' c .. r, .-...irk is pe; I,.friuo on the apparatus. t..; t"..i t<ie. c ;mciJ3 with Monsanto's pubfrshcJ specifications. 060660 ? j . nr.t c. -jnu.-. J .ill tuples. W/11a us for complete sales specifications for Askarel fluids. TOWOLDMONOQ40476 operating askarel transformers -- take every precaution to guard the a:>.o'c.f insulation from exposure to high humidity and moisture contamination. Keep 5 or 55 gallon drums of askarel Pry; lay stored drums on their sides 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 indoors, 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 than 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 200Ch`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 m3y 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 extreme low temperature conditions. Convenient handling and pumping temperatures are given in Table HI. * Use Ordinary PersonalPrecautions: Transformer askarel has been made. handled, and used for over 40 years. It can be handled soniy with recommenced precautions. 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 ~r,d Pumping Temperature C Pyranol A13B3B-3 Inerteen 70-30 Inerteen 100-42 20-55 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 dean saturated clotning. Clean up spills with rags, sawdust and absorbent clay. Eye contact m;y result in painful iiriiat'on hut no permanent damage to tissues. If askarel gets in the eyes, f.'usn with Ijroa amounts of water. As with all eye fust an!, tehi to a physician. To (ciievo irritouon, physicians hove used an on:'; du e anesthetic solution as well as opthalrruc cortisone acetate solution, or castor oil. Infuqueni crpount to , ;.ai el Vdpurs will < Ha.'.i\i i, proluiyA e' r. to hi ,h vapoi cc he avoid-11. If hot j;k. must he nan t1, d m .inn, provide the- urt-a u rn, rh ,:iir -1 i-diu n 0686608 TOWOLDMONOQ40477 wear an organic cartridge respirator approved by the U.S. dureju of Mines. C. Precautions On Opening an Askarel Transformer: Askareis 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 and celiulosic or other organic materials may, when arced, produce caseous 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 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 instruct,ons and cu.dance "For Acceptance and Maintenance of Transformer Askarel In Equip ment". This guide is published by the Institute of electrical St Elec tronics Engineers, me., 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 askare's contain polychlorinated biphenyls (PCS.) which have been used in the United States and elsewhere over the past 40 yars for many industrial and consumer applications. During the past several years evidence has accumulated to indicate that PCBs are widely dispersed throughout the environment and that they can have adverse ecological and toxicological effects. The United States Government's Interdepartmental Task Force on PCBs, Com-72-10119, in their March 20, 1972 report titled, "Polychlorinated diphenyls and the Environment", recon m.-nded restricting PCBs to use in capacitors and transformers. This report n di`tnbutc-d by the National Technical Inf. r-'-fon Service, U.S. Dcpar ment of Commerce, Springf eid, Virginia 2 i; A document titled, "Guidelines for Handling ano Disposal o* ( .. '>rnr and Trar.tforme Grade Askarels, Containing Polycn u i:::j Biphenyls", nas b:en prepared and is available from the t -ven National Standards Institute, Committee C107, 1430 Brocu.v ;y. New York, New York 1O018. The scope, objectiv s 2nd the composition of this committee a: ANSI Committee 0107 Scope: Procedures ard guides for safe use, maintenance and . . _f askarel and 3'<arc!-soaked materials used in electrical r ; . - t. Objectives: 1. Source of technical information and advice State, lot al authorities and ali others concerned 2. Enrojr.ite development of suitable disposal keep all concerned informed. 3. Serve as :nc advisory group for United States im- mah inji organizations; CEE, IEC, CIGRE. r 'n, . .? . ' in Composition; Organizations active m or represented by this ANN include: Nabcnjl Electrical Manufacturers Associav.m : Industri-s Af ,oc a'uon, Institute of Electrical .r ' Cr,:j'rs, Ar.c::c.;n Society fn' Testing and M.i' l. 1 A e. > AsPun. Certified '' ,\;;e .r-i'u; l e. m me M.J Pmtection \i f 'V. " 't _! % urn, I ,il j u r v'tO's II. 1 1 : - . ' 0686609 TOWOLDMONOQ40478 B-tcjj of Standards; Department of the Army; Rura1 Electrification Administration; Division of Environmental F.c'.-.wch, TVA; American Public Power Association, W.iter Pollution Control Federation; Food and Drug Administration; National Fire Protection Association; Underwriters laboratories; and several sections of the U.S. Department of Interior. The fo'lowmg are pertinent excerpts taken from the ANSI Guidelines for askarel transformers: 1. LABELING ASKAREL TRANSFORMERS (Pg. 16) 4.22.1 New Transformers. AH new transformers that contain PCBs shall have a label of adequate durability, permanently 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 {.PC8sf 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 for use on existing transformers. 2. DISPOSAL OF LIQUID AND SOLID WASTES {Pg. 15} 4.1.6.5.1 General. Disposal of oskarels and askarel-soaked materials should be accomplished by means in which-there is no significant release of askarel 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 been 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 end, finally, suitable scrucbcrs to remove the HO that will be formed; for example, 2-second dwell time at 2COOF ar.d ,,?% excess oxygen in stack gas, or 1.5-second dwell time at 270(TF and 2ic oxygen in stack gas These facilities should meet the applicable requirements of the state in v.hich they are located and should control effluents within the limits set forth in this standard. Controiled landfill or deep-well disposal con be used where permitted by federal, state, and local regulations. The ANSI Guide lists the locations of facilities that conform with the above recuiremer ts. Monsanto has such an incin erator at the W. G. Krummrich Piant, Department S31, Sauget, Illinois 62201, wneie arrangements can be made for scrap askarel liquid dispostl for a modest ice. 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 un/t shouid be located either m the storage tank Oreo or in the main transformer manufacturing area for i,Ping with askarel. 4.2. 1.2.2 i\..'-jf's Conditioning of new .rr! or recycled asi.vc! requires fuller's earth treatment. The spent faker's earth in cartridges ur bags, when replaced. be allow </ :<; dram tncrougfdy rv-"- ,-ip pans to remove as much liquid askarel as P:c ce't'idge units of steel coictruct-on v.v. , laced m toe "STl.LL CP ,7- T.-WHNA VF.D WITH A SC Aiit. i" cont.-.ner for u..pus-t.on. 0686610 TOWOLDMONOQ40479 4. TEARDOWN OF TRANSFORMERS FOR REPAIR OR SCRAP (Pg. 16) 4.2.1.4.1 Dra.r, a7 jsk.irc/ from the unit other m;o j holding tank or reuse or into the drum labeled "SCRAP 0 ASKAREL" for disposition, and 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 askerei-fiiled trans former may be accomplished in either of tv/o ways: (1) Complete drainage and dismantling with the proper disposal of the askarel and askarel-soaked components cs - described in 4.1.6. . (2) Disposition of askarel transformers by means of junx 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 lejst 30 years. Since their introduction in 1932, the manufacturers report 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 r, te for askarel transformers as 0.13 per hundred banks per year. Mr. Frank M. Clark, .vho invented transformer askareis at the C r-'crei Electric Company h the early 1930s, made the highly pe tmen: comment basea on tis many years of experience with G.E. F /renol (askarel type) transformers that -- "The important thing is to keep them dry - otherwise iej.- ' them alone". These words or wi.c om became especially applicable in moi.* pce-nt years when welding sout rather than gasketing became the mam m-rmo.J of sealing askarel transformers. These units are sold wt n pu understanding that the liquid is in a normally hermetically ciowd system. X. General Char; iteristics of Transformer Askarel Fluii _ Appreciation of thi following characteristics, as given m th? \2cl Guide, leads to understanding the reasons for selecting d eit'ctnc breakdown voltage and moisture as the prime practical tests n juern.* the quality of transformer askarel fluid. Also, due :< t:w ? characteristics the pjwer factor of transformer askarel will be n jrm.Jiy much higher than th : corresponding values for mineral oil. In comparison to mineral insulating oil, askarel is a relative / pour material; i.o.. d.- rnc:ecu!c$ are dipoles, free to rotate .`.round t>- -n . and responsive to ouentation by electrical forces. Askarel jiso 'imms a much higher dull ett ic constant and capacitance than msu!' '' - 1 and these didwenct s must be kept in mind when mterprmmg < u v *...i test data. n.w- Mjse n I'. rr-Lii.si ly pol.n, and possesses high solvency now. ' . -> ,, m.u-ls mmi ete itnc.illy sensitive them miner..! ml ; j n . rM'.menus vc'h:h!u polar materials, and comenuv!itl> me d . . 0686611 TOWOLDMONOQ40480 constructional matt'riafs a:stmt'd tor use in askarel is very cntical. Tins :,,nr-iv'Tv is rejected in The power factor and resistivity (specific esiiUncs) 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 res'Stivity (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 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 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 Now Equipment Some users of askarel equipment find it desirable to make "as received tests" on all equipment. It is qui a 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 oe obtained from the power factor, color, and moisture content tests. In sampling askarel contained in apparatus extreme care must be exercised in order to obtain a representative sample. ASTM Method D 923 should be followed. Now equipment with askarel exhibiting the following characteristics is considered acceptable: Dielectric Breakdown Vo'tage Color Condition Visual Water Content Power Factor <;t 2`Jt C 30 KV min. 300 max. (Straw color) Clear 35 ppm rr ax. ASTM Methods D 877 D 2129 D 1702 D 1S33 *The power factor of askarel taken from new tr jnstorrr.v r$, rc.'*n:o<$ and accessory equipment can reflect the presence of mmsture, dissoUod polar compounds, or other cont remnants .and m.;y v_ry with the type of cqu pment irern wluci'i tne ;-npv .j5 taken due to the different tutus of liquid to-soUl n ,,u;..hon . ;.J to the high solvency power ql the .,h..i<ei. C. 1 .in cep: ' `e water content cd u.i iei tr u hieikoown vul\..c et Me . ............... indicated above, a high power lector i.-hueii iii'- n. ; m serviceability of the askarel within ' idui btO.Nt ImiM, v b) 0686612 TOWOLDMON0040481 indicative of the degree of extraneous soluble Dotar m3t:nai* 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 wnich would be acceptooie to bom suppliers and uc-_-rs for all applications. However, as a broad guide, power factors up to about 10% at 25*Cand 60 cycles per second (hertz) do not m general indicate any abnormal contamination prov.dmg that the other criteria {water content, dielectric breakdown volrace, 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 De investigated. Xlll. Dielectric Breakdown Voltage -- Moisture Relationship The dielectric breakdown voltage of askarel is highly sensitive to excess moisture; not sensitive to ordinary dissolved poiar materials. While the dielectric breakdown voltage can also be lowered by severe rc;ng, askarel turns noticeably black or has particles of sooty carbon floating in it if arcing 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, aremg, or both. When the dielectric breakdown voltage has dropped to 26 KV or less, an 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 askarei drops below the value required for efficient insulating. The moisture c ontenr should not be allowed to rise over 70 ppm. sampled at o;.?ra:ing temperature. If the moisture content is found to be in a satis -etory range and the dielectric breakdown voltage is low, the trarv ;prmer manufacturer should be consulted. Table IV shows the relationship of dielectric breakdown vo! vs. moisture and Table V indicates the approximate water sdubiM/ limits in askarel and miner I oil. I Table IV Relation of llizieetric Breakdown Voltage to Amount of Dissrlvui \ .'ster in Askarel and Mineral Oil Water Content (PPf;) Breakdown Voltage (AST'l D3771 Askarel Mm -rji 0 70 KV ` 0 KV 20 55 ; 9 40 47 : o 60 40 80 38 110 10 5 06866X3 TOWOLDMONOQ40482 Tabic V Approximate Solubility of Water in Transformer Askarel and Mineral Oil `C. fF. Amount of Water (PPM) Dissolved Askarel Mineral Oil 20 22 20 4 10 14 0 32 10 50 20 68 20 86 40 104 8 16 28 41 65 94 128 170 8 10 13 20 33 58 85 130 XIV. Turbidity ., . may be the visual sign of undissolved water, or may indicate 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 15F above zero. To rcaissolve it requires heating to 150-200F 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 IASTM D1533-601. The dielectric breakdown voltage test lor 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 askarel transformers with welded construction or silicone or Viton* gaskets (hand hob-cover, switch and terminal compartment covers) and with properly constructed bushings require little maintenance. With properly constructed trans formers, annual or semi-annucf visual inspection ond dielectric bieukdown voltage test of the askarel fluid should suffice for routine maintenance checking over many years of service. However, many askarel units wer? 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. Lf.tky or deteriorated gaskets should be replaced. If the askarel l.as become contaminated, it should be reconditioned. Ai the same time, a general clcan-up of the unit and possible rcfinicntng may be ('Sirup:?. j j I If it is not convenient to take an o:d transformer out of service for / g moral repairs, leaky gaskets can b: sealed temporarily by painting l over the Laky area w.th epoxy cement. A survey of users indicates a emed number of curly bu.lt a-,*oiri li,,'v;t'niTurs lover 20 years old) die kept in continuous .or vice m ii tjl!..: ons by the following steps (uritvd of : .o I 'ii'ii'jPun), * i h-_ i'i erjfuei mnlS are equipped with COinpOuu ' Pfc ssure ;;..i : -s tor rr,tiling pn ..nit: ..:>ovo on,} l.v'lmv .ilmn j.iiifu' Ik'n'i \r i < '< n .ai i Oi.f. .-t C ll n 1 jf r I!:; I li I 0686614 TOWOLDMONOQ40483 pressure is maintained on the shell by introducing nitrogen at 2 :o 3 pounds above atmospheric. Regular workmen m tne amj . 'y record the temperature and pressure. It a sudden pressure crop n noted more nitrogen is introduced and the gaskets are checked tor leaks with soap solution. Leaks are sealed by applying epoxy cement. B. Modern Sealing Procedures: Transformer purchasers should specify the following modern 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 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 t3nk 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 poicelain ' . 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 g ass 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 % inch thick. Bushings with recessed grooves are suitable to use with cork, cork-nitrile rubber combinations or nitrile uboer as well as gasket materials such as silicone or Viton. 3. Small Size Connections: When not possible to weld smell size connection seals should be made with Flex ta.iic.* stainless steel rings. The surfaces must be machimd and parallel. The filler between the steel laminations d the Flexitalhc ing should be either silicone or Viton. 4. Gaskets fcr Hand-Hole Covers: Modern design sp.-edied silicone ga.kets. Such gaskets must be retained in a cx-a.-e. The groove preferably is machined into the flange or cover. However, it can also be formed by welding concentric .u.el strips to the flange or the cover. Generally the gaskets i-cu'd be 5/16 to 1/2 in. thick for covers, depending on the u urn of the gro >ve or stop. A rectangular cross-section is usually used. The silicone material should be Dow Corning No. 50 Silastic** or equivalent. This is a low comtvrsst set material. For best sealing 20-25% compression is recommended, with ample clearance in the groove or stop to allow for this compression. No cemen' is required. With reasonable care tne gj>k-t is removable vithout damage and is reuseable. . Silastic DO is slightly swelled by askarel which contnb it'-s to the tighine.s of the seal. It is not deteriorated by askar* i `h.'d or vapors, it resists weathering and it is thermally stal u: .;'d t (. 1 .'..ii k ()l i i-K'U >>: G.iUmU C.mi|..iny * * k ot Ouw C< rmng 0666615 TOWOLDMONOQ40484 flexible at s'l operating temperature?. It is an excellent NOTE: Dow Coming, Midland, Michigan will supply a list of Silastic 50 gasket fabricators to all transformer manufacturers or users. They will also furnish technical data. See Appendix J: Seals, Properties and Procurements. C. The Older Se:l:ng Arrangements: The older type gaskets consist of either cork or cork-nitrile rubber combinations or straight nitrile rubber. 1. Cork-Nitrile Combinations: Covers tor the main tank, hand-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 Snellac {Westinghouse Style No. 1150419, or General Electric Company's Glyptal* 1276) 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 B614G01, (about $15). The joints - and also the gasket - should be cemented to the fiange, using one of the above cements. Excess cement should not be allowed to reach the interior of tne 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 wfveh a cubing catalyst is added immediately before use. Typic:-' :;re: a. Epoxy Patch Kit el-C Hysol Corporation, Glean New' ork b. Scotchcast** Resin v4 Minnesota Mining & Manufactui :ng Company St. Paul, Minnesota c. Adhesive A-1 and Activate Type 3 Armstrong Products Cormony Argonne Road, Warsaw, Indiana d. Adhesive 9860-1, Synthetics Organic Company, Cleveland, Ohio, used with activator diethylene triamine (C3tbide and Carbon Che nical Company) 2. Straight Nitrile Rubber: When straight nitrile rubber was ongmaily used, invariably the gasket was recessed in a groove. This was to prevent gasket flow and to protect the material .-nans: excessive compression. Although this type seal was net cemented, the nitrile rubber gasket is not reuseable. S ore grooves or stops have already been provided for the nitrile rubber seal, Silasuc 50 can be easily substituted and is ri ..un-.ruvnai J, This conforms with modern practice. XVI. Petn dic Fluid Inspection and What Checkpoints Mean ..'i '..'.Pule - at six, nine, Or Hv"lvc-month inu-rv.i'S - nuke ,i siinv uuiii insjj.'ctiun ui your jskdiul insulation arid i un a d.-. lucti >C C :> npjfiy 0686616 TOWOLDMONOQ40485 A. Visual Inspection: Askarcl is a clear, famt-yellow liquid. After long-term use this color may gradually intensify to ligrtt brown. The fluid sno-.J 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 .ndicate an arcing condition. Other color changes alone are not danger signals since the . .. dielectric breakdown voltage is not likely to be impaired. B. Dielectric Breakdown Voltage If the dielectric breakdown voltage has decreased significantly from the last inspection, or if it has gradua'ly decreased below 26 KV range (at 25aC) - RUN A CHECK FOR MOISTURE. Use - ASTM D1533 (Karl Fischer Method). . . The dielectric breakdown voltage of askarel is the major indicator to the operating efficiency of your liquid insulat'on. Besides me visual inspection tests, dielectric breakdown voltage rs 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, XVW. Inspection Checklist 1. If 2$karel is clear -- even though darkened to light brown, has no sediment or turb'dity, 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 itst If, an operating hazard when the dielectric breakdown voltage stay:, over 26 KV and moisture remains low. However, this rare occuu snee calls for checking into the condition of the interior constr trnon and consulting the transformer maker. However, when sar bang the fluid care should be taken to avoid getting color into me ' askarel from pain that may be inside or outside of the s:inpl> valve. 3. If the moisture content is found to be above 70 ppm at op< ating temperature, th n sampling should be done at more iriQuent intervals to establish a possible trend, particularly on oi .-djor installations. 4. If askarel is c!ea-, but dielectric breakdown voltage drops tc 22 or lower KV, and moisture rises over 80 ppm when sam; ad at operating temperature . . . the askarel is ready (or .mole "refining". If the moisture is near the saturation level iaooj: 125 ppm at room temperature) a thorough inspection should t> nude for water dro 'lets in the transformer tank, and ev n for "globules" of vsater floating on the askarel surface. If foui J, the transformer ma .ofacturer should be consulted for re-condi -onnig both the transformer and the fluid. 5. If askarcl Ujtri brown to black, <f black particles of cart on are smn. and cioicctnc strength is low .. . the askarcl lias been noken down by arcing. It cannot be refined and should be rvmo- - d md iroivra'.vu m u r p'oper conditions. (See ANSI Commit;* CIO? report on Use and Disposal of Askarel and Ask,,rt'lSr.u-,t\/ f.'jtvrials. 1*30 Broadway, New York, New York 10013. If uny cf t.V five simple inspection tests appear out of in, ordinary oi th . r* 1 ,.t1 unship between jpyear.mce and test jbnnrrn.it, coi ,-act your transformer supplier for ,i c. l1l:.)' L;i-t* shnipped tIOo fl.V'-i'rvv, mUUmO. pi-.i a (o und-y: "GAMBLING ASKAREL". i;>" 0686617 TOWOLDMON0040486 XVIM. Contamination in Transformers f,'., c.'gti natter and orccd decomposition products ore known to be serious contaminating influences on transformer askarel. The power factor test normally used for the detection of contamination m mineral oil (Hied transformers is of little use for th.s purpose in askarel filled transformers, due to the extreme effect of extraneous so'upIk polar materials. Tnis increase in power factor as illustrated in TuS.e Vi has no adverse effect on dielectric breakdown voltage. Table VI Effect of Common Insulation Materials on Power Factor and Dielectric Strength (Heat Aged 96 Hours in Askarel at 100C.) Material Immersed Askarel After Exposure Power Factor, Dielectric Percent at 60 Strength eye., 10CTC 25C, None (control) Black varnished cloth Copper Pressboard Manila paper Phenol formaldehyde resins Shellac Iron Synthetic rubber 1.0 85.0 1.5 2.0 1.5 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-resisti-ity of askarel, without affecting its dielectric breakdown voltage. This i-; shown in Table VII. Table VII Effect of Common Insulation Materials on Volume Resistivity of Askarel Sample Volume Resistivity x 109 ohm-cm (at 10CTC..500 Volts DC., 0. V* oap) 1. New askarel before heat aging 2. New askarel after heat aging 96 hou*s at 1 C0C 3. Aft?'' heat aging with 1 sq. inch specimens of: a. P:.. nohe resin top changer material b. Paper c. Gr?dn A p'essboard (tan) d Gr;:::e A pressooard (gray) e. Gr^de A pressboard, laminated stiip ' f. Cotton snapping g. Giyptal 1276 cement, cured 48 hrs. at 110*C 2,000 1,900 i ,200 750 500 500 400 300 ICO While trace contamination easily lowers volume resistivity from high levels, it is important to note that heavy contamination (as when arceo) does not lower the resistivity below the order of 10-1 ohm-cm. at 100 C. The cvffi'n.'nt behavior of askarel vs. mineral oil in tiiese respects can be sumn j' . j as fni'ows: High power l..ctor and low volume icsistivity m transformer rn.m.!: j| o b .-'e commonly re'jjfded as "danger signals" that :ne oil nos U-riorated and broken down chemically or ->'ve rnoiS'ue is piesent. Thi; t; NOT ThUi' o' ,i A.uel liquid kv.ukit'on unle s the du-lectr <c bnv* drwn \ alt lew or tri<* moisture Cont '-H is h.-th. I 1 TOWOLDMONOQ40487 A Manufacturers o( askarei type transformers point out that d is cm.well known that askarei transformers with initial power factor of askaiel flu d in excess of LJ v a: room t<imr.:'c:ore a: _ i-Z : . -c satisfactory service life. However, there needs to be assurance tnat tom 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 askarei resulting from its controlled exposure to insulation and construction materials, in order to evaluate their immediate major "contamination'' effect on the askarei fluid. Delayed or long time contamination effects may not be detected. The method also utilises various physical tests on the insulation and construction materials after controlled exposure to the askarei to determine the compatibility of these materials with transformer askarei. Properly proportioned specimens of the insulation cr structural materials are immersed in refined askarei for 168 hours at 100 VC m a forced draft oven. Changes in electrical and chemical properties of the transformer askarei are compared against a control sample of tne askarei treated in the same manner, in absence of the test specimens. Dissipation factor {ASTM D 924) charge is one of the criteria used. The askarei fluid is refined by absorptive treatment to a dissipation factor level of 0.05 max. at 100'C and 60 Hz and 0.01 max. at 25*C and 60 Hz. Corresponding values of the askarei 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 askarei after heating in presence c the test specimen are 0.20 at 10CFC and ^0 Hz and 0.04 at 25`C and i 0 Hz. XX. Refining Asicp.rel for Reuse A. Filtering Through Dry Blotter Paper to Remove Motstur md Extraneous Port' les: Most operators prefer portable refining apparatus, such as c pme press fitted win a dolly, available from Sparkler, Mum i \ Illinois or General Electric Company, Pittsfieid, Ma;suuhu;c.; . the earthen cartridge filter type available from Industrial i1 ::i Corporation, Lebanon, Indiana. Filter paper liners for nm * . press are availal ie from Carl Schleicher and Schucii Cm : Keane, New Hampshire and manufacturers of filter pieces " l above. The filter paper must be dried immediately before use. F results, spread no paper for maximum surface exposure u 't air circulating oven and heat it for 4 to 6 hours at 11 ChC. Circulate the a;<arel hot {but not over 4CVC1 through 'n ' ' ' fitted with the cry paper liners. After filtration the dielectric breakdown voltage ot 'm ' should be 35 K\ minimum. PRECAUTIONS: 1. FitUnn.j .hculd not be dene when the rel :u' exceeds ' 5%. 2. Any flex ole hoses jnd gaskets on the rcfning . : . should h ' lined with or made of materials U'.;; be softe i'.'d by contact with askarei fluid. " ImeU wi n Silicone, Vi'.on or uUon* or i material? are suitable.) *Tr.\i<'ni;ak c f f 1. Du ont O^Nemours & Company, Inc. 0686619 TOWOLDMONOQ40488 S. Make cure that the askarel is at least as warm s the surroundir^ air. (Cold liquids can condense moisture from humid air.) C. When sampling askarel from transformers, it is best to take the Sarny.e /.hen the unit is warm and operating at average or _ mar mum load, especially for a check on moisture as reflected by a 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 sample should be destroyed by high temperature incineration described in Section VIII. - . r f ; r i . . . . .... TOWOLDMONOQ40489 w fij S*tt5yFt<'<Cli7!S5 t*i r-n ^ a 7n 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, and the high voltage leads are connected directly to the switch terminals. They may be filled with either askarel or mineral oil. rroottaarryy oorr ddrruumm ttyyppee ffiitttteedd wwiitthh aa rreevvoollvviinngg bblloocckk uu,,..ww FFWW.. uu..mm the principal element arranged for three-phase service. . 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 rubber-and-cork particles were used. While satisfactory for a limited period of time, these materials cannot be depended upon for the expected long nfe 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 tcmmal chamber is below the switch, askarel can drain into the terminal chamber. . II. Sources of Contamination There are three possible sources of contamination for asktrel m switches and termina chambers; they rank in this order of frequency: (1) water entering tt rough poor gaskets; {2} decomposition pr jcjucss from arcing when switch is used to break magnetizing current, (3) entrance of porhead or cable compounds through leaky bushmc seals. Unlike an askarel transformer where the amount of contaminant is likely to be very smll (probably only trace amounts! in relation to tne volume of askarel fit id -- in switches or terminal chambers with feu'-y seals, the amount of i ontamination can be relatively large. Experience has shewn that, based on the number of irstalled askarel-switch units, the percentage of failures is extremely small, '.'.hen investigated, it has b :en found that most failures originate m the switen chamber. Water is the chief source of contamination. However h^avy contamination of as .arel with petrolatum and asphalt material, oue to leakage, have caused a few failures. Petrolatum is used frequently for filling terminal chambers. Wher cither cable oil or petrolatum seeps into askarel, no great harm resui.s. The fire resistance will \)o somewhat decreased and power notor of me 3skarel will increase with un accompanying drop in res.snvity Wmie highly undesirable, n is doubtful that failure of the unit msuits Wnere asphaltic compounds art* used m place of petrolatum, tnj u< ~.r is increased somewha: because asphaltic contamination may c:u-,e excessively high dicli ctric losses in the askarel. When the terminal . Panther is below the switch cumber, the compound can be -out imuuvcf by .v-k.irel if the bu^ nq sirs me leaky. Tins is umi' ir.ibln because the askarel will incnw-e the i factor and conduct vrtv of the {lotting compound or C..P!-1 "I , id develop Ins.I bom uu-l -etne loss If this mixture r, drawn m.tn tt u: TOWOLDMONOQ40490 insulator., c cable falure is likely. This sga>p emphasizes lb importance of tight bshmg assemblies. III. Sealing Switches and Terminal Chambers Proper bushing construction, use of Silastic seals and welding wherever poss*b/e is h-ghly desirable fas covered in Section A). Where an clastomerc 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 grrsneements 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 is 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 in this type of apparatus can produce excessive and prolonged arcing and accelerated deterioration of the askarel. It is recommended th3t when askarel is used under these conditions, checks of the liquid, especially for moisture and dielectric 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 wiil depend on power interrupted, time and frequency of operation. As a general rule, the liquid should be checked after 5 to 10 operations. 1. On newly installed switches, check the askarel at 3, 6 and '2 month intervals; if found satisfactory, check once annually thereafter. With proper attention to tns gasketing of covers and bushings, experience will probably indicate that less frequent inspection is warranted. 2. Check askarel for: a. Dielectric breakuown voltage (ASTM D877): It should be 26 KV minimum, 'f dielectric breakdown voltage is low, confirm presence of water by Karl Fischer method ASTM D-1533. Filter to remove moisture. Dielectric strength should then be 30 KV minimum. b. Presence of carbon from arcing: Fluid should be relatively free of carbcn. If badly axed 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 5% at 25'C and GO cycles). Flush out switch chamber with several gallons of fresh askoiel before refilling. 3. If there is discoloration, hig i power factor, detectable change in specific gravity or rofraci've index, or if fluid flashes below 253 F, ;lv. :e is o pu.sibiMty of seepage of petting compound into thy switch comportment. In this care, correct any Ivky b.mning s.^ls wall proper replacements and fill with new A. If ten"anal chamber is below switch, chock potting cnrr.po.Hvj for pr-e,i nee of oskarcl lean usually bo a aoct-tl by o.ior or by an increase m spoonc gravity). If askarel .> P'iscDI, correct any k\Ay buai'ng si/ais w>;:i pne'r rcppvvnn nts, and renew coinpounn... 0. us,.mine cover g.:A -as visuu,lv. (''..tenor ruun con bo b :emu by swelling and cracking of the expu-,.d eda*. I.i c.v.,.s -f severe deterioration, liquid seroa.se is usually present. 6. Check lor Ic-axac: at pocking .::ur.q of sv..tc:vrj , . i* 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 askarels begin to boil at temperatures of about 205'C, under atmospheric conditions. If the material is heated to such high temperature in 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, sealed askareMillcd equipment be provided with pressure relief devices. . >c These devices must be large enough to provide immediate relief at a definite pressure, and to prevent further build up of pressure if 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." o' C .1 rr~n id o c? < -^ r h n ,-s > r: 1 i. Inhalation At ordinary temperatures the chlorinated biphenyls in Askarel hav' not presented industrial tcxicofcgicaf problems. The hazard of pun nual toxic exposure varies with their volatility: the lower-chlorinated, morevolatile ones present n ore of a potential problem from the stand >oint of both inhalsron ami skin contact. When Askarel fluids arc us ;d at elevated temperatures engineering controls must b? applied, eirh r by the use of closed systems or by effective local-exhaust venti ,tion together with caneral vrorkroom exhaust. Vapors of Askarel at room temperature should not be breather in a confined space, and no vapor of any fluid evolved at e'v.ss.J temperatures should be allowed to be dispersed into the g ncral workroom. Inhalation tests on an.mals indicate that the maximum rate concentra tion of vapor is in the range of from 0.5 to 1.0 milligram pcr cubic meter of air, The thnshoid limit value {maximum allowable ct oc?otration of an 8 hour working day) set by the American Conic coca of Government Hygienists are 1.0 milligram of the lowar-chior m'rd biphenyl compounds Per cubic meter of air end 0.5 milbjram >t the more-hichly-chlorinat1 d compounds, per cubic meter of air. 11. Skin Contact Prolonged or repeated skin contact with the Askarel fluids m v. he avoid'd by the use cf gloves and protective garments, because -n tnu possible occurrence of a cond.tion called chioracne. Althouu . i v-t; of this condition cat md by Askarel are rare, it can be predu. . d lv excessive skin contac.. If tne fluid is spilled on the skin the s- m . e.nd be washed in the usut: manner with a soap solution. A burn cuus.d by co 'tact with a hot Askarel should be tr--ate ' n- j^v orci.njry bur n. :`,-r .if nr-uns ol A'X.irtl fluids, s.w* .c. ..lor) h VI!! " C686623 TOWOLDMONOQ40492 /In: r. Si 'liteiSuGaSTi'SE' /^?Lf-SSireii i ^ r-VTT t*--** [7 /' rr- r*~-or- "ansformer users not wishing to make their own fluid analyses can obtain the service from Monsanto. Simply contact Monsanto ?rcf specify w-hat analyses are wanted. You wilf be sent the proper-sized, clean sample container, fitted with a proper label. When yoj receive this, carefully take your sample {following the procedure for sampling in this guide). Send the container to Msmsanto's laboratory. Charges listed include sample container and laboratory costs. The charges are those in effect March 1, 1 -75, and are subject to change. Types of Analyses Available Analysis 1) ROUTINE MAINTENANCE CHECK . .. Total Charge: $30.00 ... . To determine the general condition of the fluid and find whether further analysis is necessary, (one-quart sample required) Properties Tested Dielectric Breakdown Voltage 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 five-pint sample container. This sample will be used for the following series of tests: Analysis 2) COMPLETE ANALYSIS Total Charge: S75.00 {1) To determine the extent of fluid contamination, (2) earth refinement to determine what degree of restoration of electrical and insulating properties is possible, (3) check test to see how the fluid responded to earth treatment. ' Complete Analysis: to determine the extent of contamination Properties Tested Free Chlorides Color and Conoition Acidity Specific Gravity Dielectric Breakdown Voltage Refractive Index Power Factor, Dielectric Constant,. nd Resistivity Water b) Earth Refinement Response: Consists of treatment for 2.5 hours 3t SO-CQX. with 0.1 to 0.2 percent by weight of properly conditioned Attapuigus c: / and then filtration through dry filter oaoer. cl Analysis After Laboratory Earth Refinement: Properties Tested Acidity - Refractive Index Dielectric Breakdown Voltage Water Power Factor, Dielectric Constant, ind Resistivity Free Chlorides You will be notified of the results of this test series on your sample. Then after refining your entire transformer fluid fill y can check on the results by requesting the following analysis: Arv'ysis 3) ANALYSIS AFTER EARTH REFINEMENT Total Charge: $50.00 (This charge will not apply when analyses 1 and 2 have already been madf.) To determine whether the entire lot of the askarel fill rcsoonded to the same ext> nt as the laboratory sample, (five-pint s.im; e .JTjd) ''cpirtics Tested Cchcr and Condition Free Chlorides Acidity Index Dielectric Breakdown Voltage V.Gter Power Factor, Dielectric Constant, c-nd Resistivity .:".'n?!' -'or the torts cv^-ribed above write to the fo'lowinn address: David Wood Vo"'..r-to Inoustfn:- Chemicals Company St. Lou s, Missouri 03160 ..('."pii'S to t? t.-Stott slioi ild tv clearly marked tor itmntif ic.itio Y...n:..rUo Co'*':v nv W. G Km: rr.-m 1 ` am-y r. ' -T -v- '.TGI 'f i: R. Kuster and sent da :iiy tc; 068662*1 TOWOLDMONOQ40493 APPENDIX A Arkarel Stability and Composition of Arc Formed Gas: Askarel insulation is one of the most inert, chemically-stable heat resistant, non-corrosive liquids known. !t will not break down, oxidize or sludge when exposed to air and high temperatures, 150"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 G (INERTEEN 70-30 AND PYRANOL A1353B-3, RESPECTIVELY) Gas carbon monoxide carbon dioxide oxygen inert gases ' hydrogen chloride (note the absence of phosgene) Amount 0.3% 0.3% 0.6% 1.5% 97.3% This arc-formed gas from ASTM Type D and Type F transformer askarels is non-flammable and non-combustible. For ail 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 TRANSFORMS i ASKARELS ASTM TYPES D AND G Carbon dioxide Air Nitrogen Hydrogen chloride1 Jln absence of scavenger Percent of Gas 3y Volume Corrected to: 25*0 760 mm 25*C 1C0C 0C. 760 mm 25*C iooc 71% 5.7 6,0 37.8 47% 4.3 4.8 50.9 - 5.8 5.0 5.5 4.4 -- APPENDIX C_________________________________________________________________ EFFECT OF TEMPERATURE ON DIELECTRIC BREAh DOWN VOLTAGE OF ASKAREL Temperature PC -60 . -JO -20 0 20 JO GO cO Dielectric Breakdown Voltage ASTM D877 67 KV 63 57 55 50 50 48 45 0686625 " ) ) )) . TOWOLDMONOQ40494 APPENDIX D COMPARISON OF THE APr'P.OUMAT2 VISCOS TY IN SAYSOLT UNIVERSAL SECONDS OF TRANSFORMER ASKARELS AND MINERAL OIL " Temp. *C -20 0 20 40 60 80 100 Pyranol A13B3B-3 1,000 100 70 45 39 34 30 10-C Mineral Oil 1,000 150 85 49 40 34 30 Inerteen 70-30 2,800 195 85 50 40 36 33 APPENDIX E THE DENSITY OF INERTEEN 70-30 AND TRANSFORMER PYRANOL A13333-3 Approx. Density gm/cc. ........ Temp.*C 0 20 40 60 80 Inerteen 70-30 1.574 1.552 1.529 1.507 1.485 Pyranol A13B3B-3 1.577 1.555 1.532 1.510 1.488 ` . / '** . APPENDIX F_________ _____________________________________________________ ___________________ - The thermal conductivity values cf transformer Pyranol A13333-3 at 27*C and 58C are 26.2 and 25.8 x 10'5 calori-.-s centimeters-1, degrees centigrade*1, second-1, respectively. Or, approximately 0.06 BTU per (hr.) (sq. ft.) (*F.) per foe t. This same approximation applies to Inerteen 70-30. APPENDIX G__________________________________________________________________________________ Heat Capacity Over the temperature range of 25* to 125*0 the specific heat of transformer askarel is close to 0.30 calories per gram p *r degree. APPENDIX H__________________________________________________________________________________________ Coefficient of Expansion The sverage coefficient of expansion of transformer askarel over the temperature range 20 to 1Q08C is 0.0007 cc/cc/*C. O 12 cz'.'on would increase to 1.056 gallons on heating from 20 to 100*0. APPENDIX I F;,c- Res stance A'.:--.re1s of various compositionrl types are used. Under arcing conditions the gases produced, while consisting of p cominantly non-combustible hydrogen chloride can yield varying amounts of combustible gases depending upon tie os', ii J type. Insulation systems incorporating these askarels and collulosic or other organic materials may, when arced, produce osseous mixtures which are moderately flammable. As a precaution, such gases should be removed from the askarel by bubb'mg a. y nitrogen through the askarel and flushing \he gas space with dry nitregan befoie any work is performed on the apparatus. 0666626 TOWOLDMONOQ40495 APPENDIX J Sc-3ls, Pfor:rties and Procurement - I Oo.v Corr> ' 3 Corporation, Midland, Michigan with Districts at Atlanta, Boston, Chicago, Cleveland, Dallas, Los Angeles, 1 Nt.v York C V. ashington, D.C. and Toronto has avaiLoie Bulletin 09 019, August 19G2 entitled "Silastic Dcs.gn Data". ^ This lists tuo c::ket 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 casket 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 sheeting 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 D676 ASTM D412 ASTM D412 ASTM D395 Color Specific Gravity at 77*F Hardness, Shore A. Scale Tensile Strength, psi, min Elongation, percent, min Compression Set after 22 hrs at 300F, percent, max White 1.20 + 0.02 45 to 60 800 250 30 * AH physical properties measured on 0.075 inch thick safnples 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: 1 This product contains Polychlorinated Biphenyls (PCBs). Care should be :aken to prevent entry into the environment through spills, leakage, use, vapoi ization, or disposal of liquid or containers Avoid prolonged breathing of vapors or mists. Avoid contact with eyes or prolenged contact with skin. If skin contact occurs, remove by washing with soap and water. Following eye contact, flush wi:h water. In case of spillage onto clothing, the clothing should be removed as soon as practical, skin washed, and clothing laundered. r. n : t) L I> SSfltO MONSANTO INDUSTRIAL CHEMICALS COMPANY 5:'iiCIALTY PRODUCTS GROUP COO N. LINDBERGH BLVD. ST. LOUIS, MISSOURI 63166 Tnc information heroin regarding obtaining optimum results from askarel fiuics 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. N'otning herein shall be construed js applying to other than askarel insulation. Data and maintenance suggestions herein do not apply to the other components of .he transformer. All operating and maintenmee suggestions recommended by the manjfoct-'cr of thp transformer should also be carefully followed. ;i- cause 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. 068662 7 TOWOLDMONOQ40496