Document DdXYa51oNv9kvYjMoYOVppeKM

tJULLt I I IN NU. It/l-h-JB TRANSFORMER Inspection & Maintenance Guide ; Monsanto ! I TOWOLDMONOQ29077 SECTION A TRANSFORMER ASKARELS......................................... 1 I. Introduction......................................................... 1 II. History of Trade Name Types............................. 1 Table I - The Composition of Transformer Askarels ..........................................2 til. Interchangeability ............................................... 2 IV. Tablet! -- Official Transformer Askarel Shipping Specifications....................................... 3 V. Ordering Instructions ..........................................2 VI. Stability.................................................................2 VII. Precautions When Handling Drums, Tank Cars and When Opening Transformers....................... 4 A. Keep Dry During Handling .......................... 4 Table HI - Handling and Pumping Temperatures..................................4 6. Use Ordinary Personal Precautions ..............4 VIII. C. Precautions on Opening an Askarel Transformer.......................................5 Avoid Environmental Pollution.......................... 6 1. Labeling Askarel Transformers..................... S 2. Disposal of Liquid and Solid Wastes .......... S 3. Conditioning of New or Recycled Askarel .6 4. Teardown of Transformers for Repair or Scrap ....................................... 7 6. Transformer Disposal.....................................7 IX. Expected Service Life................................. .7 X. General Characteristics of Transformer Askarel Fluid.........................................................7 XI. Sampling Transformer Askarel Fluid ................ 6 XII. Evaluation of A&are) Received in New Equipment.............................. 8 Kill. XIV. XV. Dielectric Breakdown Voltage -- Moisture Relationship................................... .9 Table IV -- Relation of Dielectric Breakdown Voltage to Amount of Dissolved Water in Askarel and Mineral Oil....................................... 9 Table V -- Approximate Solubility of Water in Transformer Askarel and Mineral Oil ... .10 Turbidity............................................................ 10 Check Points for Maintaining Askarel Insulation ........................... 10 A. General Considerations...................... .10 B. Modern Sealing Procedures .................... .11 C. The Older Sealing Arrangements.......... ..12 XVI. Periodic Fluid Inspection end 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 VI! -- Effect of Common Insulation Materials on Volume Resistivity of Askarel........................................................... 14 XIX. ASTM Method for Investigating the Compatibility of Transformer Insulation and Construction Materials in Askarels........... 15 XX. Refining Askarel for Re-Use.............................15 A. Filtering Through Dry Blotter Paper to Remove Moisture and Extraneous Particles.................................... 15 Table VIII - Water Removal by Filtering Askarel Through a Paper Press ........................ 16 B. Disposal of Solid Wastes.............................16 C. Solid Insulation Requiring Drying..............16 D. Earth Treatment for Maximum Improvement of Power Factor and Volume Resistivity .................................... 16 Table IX -- Effect of Power Factor and Volume Resistivity ........................ 17 XXI. Cleaning Arced Transformers...........................17 XXII. 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 ANALYTICAL SERVICES ON TRANSFORMER ASKAREL AVAILABLE FROM MONSANTO ............................... 22 Types of Analyses Available: ......................................... 22 1) Routine Maintenance Check.................................... 22 2) Complete Analysis................................................... 22 3) Analysis After Earth Refinement .......................... 22 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 Dielectric Breakdown Voltage of Askarel .................. 23 Appendix D -- Comparison of the Approximate Viscosity in Saybolt Universal Seconds of Transformer Askarels and Mineral Oil..........................24 Appendix E - The Density of Inerteen 64201 KA 7336-9 and Transformer Pyranol A13B3B-3........................................................ 24 Appendix F -- Thermal Conductivity Values of Transformer Pyrarol 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 0263691 ) TOWOLDMONOQ29078 k;. ,^ p i, Transformer Askarel I. Introduction .... The term "askarel" as defined by IEEE, ASTM and the National Electrical Code generally describes a broad class of non-flammable synthetic chlorinated hydrocarbon insulating liquids widely used in transformers, reactors and accessary equipment operated at power frequencies. Askarels of various compositional types are in use. (For the general properties and types see ASTM D-2283.) Under arcing conditions the gases produced, while consisting of predominantly non-combustible hydrogen chloride, can contain varying amounts of combustible gases depending upon the askarel type. This manual describes the operating Characteristics of transformer askarel liquid insulation 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 recorhmendcd 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 very simple 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 oertain data by the following: Edward L; Haab - General Electric Dr. T. K. Stoat - Westinghouse Electric : .. . . Jl. History of Trade Name Types ' "Askarel" is the generic name for the non-combustible liquid insulation and coolant first used by General Electric Company in 1932 for their PyranoC brand name fire-resistant transformers. Westinghouse Electric Corporation uses their brand name, Jnerteen.*! , . , , Whatever the trademarked brand, the askarel contains chlorinated biphenyl - one of the best liquid insulations developed by scienoe. This inert materiel Is chemically stable, fire-resistant, heat stable, non-corrosive, and has high dielectric strength under the operating conditions encountered in transformer*, - ` In addition to manufacturing Arodor* fchlorinated biphenyl), Monsanto also 'mixes this dielectric fluid with chlorobenzenes to produce die presently used Inerteen and Pyranol blends described in Table!. . . ... 'Trademark! General Electric Company j. ^TrademathoTWastinghouteElectncCorporatlon *t > . r , *fHaj3it#rd trademark of Monsanto Company - - 0?f>369^ n I TOWOLDMONOQ29079 Table! The Composition of Transformer Askarels Method ASTM 02283 ' Type D . Iml TvoeG* Trade Names Inerteen < 70-30 Inerteen 100-42 I'yrenol . . . A13B3B3 Ingredients (% by wt.) Arodor* 1254, pentachtorobiphenyl 70 Aroclor* 1242, trichlorobiphenyl trichlorobenzene trl-telrachlorobenzene ' . . ' 30 -- phenoxypropene oxide scavenger 0.1Bto02? diepoxide scavenger Method ASTM D-2283 pending T . 80 too V;-A,'-''" 40 0.18 to 0.22 0.115 to 0.136 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 used. ,, III. Interchangeability In general all transformer askarels are interchangeable. However, It is suggested that the transformer manufacturer be consulted prior t6 v mixing In significant proportions or total substitution. , ; . IV. Official Transformer Askarel Shipping Specifications - . The official shipping specifications for the three modern transformer askarel fluids are shown in Table II. - v ...... V. Ordering Instructions 1 ' A `'* ' Monsanto's current policy is to sell 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 s'usually gives sufficient data to Identify the specific askarel fluid used.. VI. Stability .. Askarel liquid insulation Is highly pure,fire-resistant liquid made under dose chemical control to meet the exacting specifications as shown in Table II. Jt does not vary in composition like the commercial range of - mineral oils. ' \ /* ***> ' Askarel Insulation must never be mixed .with mineral dll. Over 4W6 * , percent of mineral oil by volume in askarel begins to lower 'Its fire resistance. ;. Askarel does not deteriorate when exposed tp air,beat/hot metal; It -r ^ does not break down over long use to form conducting woorroslve chemicals; it does not oxidize or sludge. Askarel will remain perfectly, stable year after year unless brdken down by severe electrical discharge. In modern transformers, the only mat "%nemy" df^askaret is . ' contamination by water, Keeping aSkard water-free wHI,insure long-time servioe - - t rv> + i^ Askarel is heavier then water, ft water gets Into atkere) insulation,only M A"3 *1V>V * irnaa uMSafurr j uijfii .lit 'l - -----K-SSh-i - -tt.4f.TJ ,*< 0?6 !<>") * TOWOLDMON0029080 p im Jfwi w- >% , ,. r*Mtt ; - ' ' -. Official Treraformer Askarel Shipping Specifications . Spegflcatidfi Propertied : .-'Color, APHA Condition . Water content, ppm (ASTM D1S33-60) Ackitty, mg KOH/g (ASTM D974-55) Dielectric Strength, 25C, 0.1 im gap (ASTM 0877-49) - Dielectric Constant, 100*C, 60 Hi.. (ASTM 092449) Volume Resistivity, IWC, . SOOveftsDCO.l inch gap,TO9 oftr^cm - (ASTM 01189) , ' > Inorganic chlorides, ppm (ASTM 01821 and v. G.E, Method E4C41B) : Refractive irtdex, 25%: (ASTM 0180?) ViMbsity at 37.8%: (ASTM D88-56) Saybolt Universal seconds : - Poor Point <*C (ASTM 0-97-57) ,, < SpecffIt gravity 25)16.5%: (ASTMOlSlO) , ,'Burrtpoint (ASTM D92) . . . DKtillatibrt range (ASTM 020-58) corrected \ for item abd barometric pressure. . Pyrmol A13838-S ASTM 02283 Type G* 150 max. ' . Clear 30 max. 0.014 max; 35 KV, min. . 4.2 4.6 . Weftinghouse Transformer Inertaen 70-30 * ASTM 02283 Type O 1$0 max. Clear 30 max. 0.014 max. 35 KV, min. 4.2 to 4.5 - . : , Westinghouse T ransformer Inerteen 10042** ASTM 02283 Type E . 60 max. Clear * 35 max. . 0.01 max. 35 KV, min. . 4.7 to 4.9 100 0.10 max. 1 6110to 1.6120 . . 44 to 48 -38 Of lower ; - 1.495 to 1.510 . None to boiling 1st drop 200"C mirt. 40% max. below Z70C 90% 379 to 394 ioo ^ ; 0.10 max..; ' 1.6153 to 1.6173 56 to 61 -30orkwef . 1.518 to 1.528 - None to boiling 1st drop 200*0 min. ' 35% below 270%: 90% 379 to 394 ' 100 . . 0.05 max. 1.6240 to 1.6260 82 to 92 -17 or lower 1.381 to 1.392 . None to boiling , . 10% 325'Cmin, 90% 360 maxi Pixed chlorine Corrosion test ; . Color, APHA * Acidity, mg KOH/g .* Inorganic chlorides ppm . . Condition ; .v..-.- Scavenger content . . Typicalftoperties Coefficient of Thermal Expansion (A$TMD1903),cm2/cm2/C Arc formed gaSes . . . Method ASTM 02293 pending for type 6. - 56.4 + 0.6% 55.6%min, . 43 + 0.5% After heating With aluminum for 6 hrs. at 200 to 220%:, the aluminum must not be corroded on either visual of weight inspection and the askarel should meet the following specifications: v 200 max. 0.014 max. 0.15 max. Clear 0.115to0.135% Diepoxide 200 max. . 200 max. 0.014 max; 0.01 max. - 2.0 max. . . 0.15 max. Clear . - Clear : 0.18 to 0.22% . 0.18 to 0.22% pbenoxypropene oxide pbenoxypropene oxide 0.0007 0.0007 0.00068 Askarel* Of various compositional type* art used. Under arcing conditions the gases produced, while consisting predominantly of norvcombustible hydrogen chloride, can include varying amounts of combustible gases depending upon the askarel type. Insulation systems incorporating these askarets and celtukic or other organic materials may, when arced, produce gaseous mixtures which are moderately flammable. As a precaution, such gases should be removed from the askarel by bubbling dry nitrogen through the askarel and flushing the gas space with dry nitrogen before any work is performed on the apparatus. 'Westinghouse uses there private numberWteeh 54201KA for Inertsen 70-30 end their private number loertaen 54201CW for trwrtwn 10042. TOWOLDMONOQ29081 a tiny amount (approximately 12$ ppm) dissolves - the rest floats on top. Askarel Is very insoluble in water, only about 200 parts per billion . of askarel dissolve In water, at normal temperatures. . ' - VII. Precautions When Handling Drums. Tank Cars, and When > Opening Transformers ' Hs The American Institute of Electrical and Electronic Engineers Guide ' : Ho. 76, December, 1958 ties been revised to give more detailed Instructions and guidance "for Acceptance and Maintenance of -' Transformer Askarel in Equipment", This guide is published by the >' Institute of Electrical & Electronics Engineers, Inc., 345 East 47th . Street, New York, New York 10017. .^ The following are significant precautions: " - A. Keep Dry During Handling , < n ,, In handling, storing, sampling and inspecting askarel - and in ' operating askarel transformers - take every precaution to guard the askarel Insulation from exposure to high humidity and moisture contamination. Keep $ or 65 gallon drums of askarel . , .. dry; fay stored drums on their sides with the bur)Q el the highest v point from floor to keep water off the drum head (which can be sucked into die askarel by the drum "breathing"). This precaution . : ,< It not necessary when drums are stored Indoor*, which is the /'- preferred place for storage. 4 . ' < . \ v, * *, *v. ( To avoid leakage the drums used for askarel are of beany construction. Sixteen gauge metal is used, with special rim seal and bung construction. The drums should be drained as completely as possible and then flushed twice with Kerosene type solvent to remove all of the askarel. Accumulated liquids and washings should be collocted and should be Incinerated at high temperatures, e.g., about 2000?. to destroy the polychlorinated biphenyls (PCBs). See Section A, V)ll,_ ^ ,,\ , Tank cars used to transport askarels ere in exclusive wrvloe ^...... ^ hot used interchangeably for other products. All cars mist be ' ! unloaded through the top (dome fitting) either by pumping ot ^' . with controlled pressure using dry air or dry nitrogen. If nitrogen * ^' has been used for unloading h is necessary to advise the Clipper ad * ' that when hie car returns the nitrogen oan be replaoed with dry ah......... ............., , before any one may enter the car. If the car is to be unloaded by < pumping It will be necessary to use a dryer withe air intake line to \ ' ' remove moisture. ' Afl tank cars are fitted with steam colts, which are available for ' s unloading under extreme low temperature conditions. . *s t Convenient handling and pumping temperatures and thertriifad " t approximate visooshy raises are given inTaWelll, / frjWjNV \ : * ** ..... - ..m .. . ' /'..(-.vr B Use Ordinary Personal Precautions* ~ h i-.-, *\ Transformer askarel ha* been made, handled, end used forover 4 yean It can be handled safely With recommended ptaw^to!K.4fj&yC**)* * * accidentally spilled on bands, no serious akin Mtadon opltt odootj* y Howevat, liquid askarel b*5 * advent action filtolfar to paint ' j* ,r^< t * `v ^ * Product ' Py-nnol A13B3B-3 tnerteeh 7090 Inerteen 10042 * TmnperttutaX Vlpfty9MS s 0?6 thinner) on the fats and oils of the skin end ptolonged contact may lead to drying and chapping of the skin. In case of contact, wash the skin with soap and water; remove and dry clean saturated clothing. Clean up spills with rags, sawdust and absorbent clay. Eye contact may result in painful irritation but no permanent damage to tissues. If askarel gets in the eyes, flush with large amounts of water. As with all eye first aid, refer to a physician. To relieve irritation, physicians have used anopthalmic anesthetic solution as well as opthalmic cortisone acetate solution, or castor oil. Infrequent exposure to askarel vapors will not cause ill effects. However, prolonged exposure to high vapor concentrations should be avoided. H hot askarel must be handled in a closed or confined area, provide the area with mechanical exhaust ventilation ~ or wear an organic Cartridge respirator approved by the U.S. Bureau of Mines. C. Precautions On Opening an Askarel Transformer; Askarels of various compositional types are used. Under arcing conditions the gases produced, while consisting of predominantly non-combustible hydrogen chloride, can yield varying amounts of combustible gases depending upon the askarel type. Insulation systems incorporating these askarels and celJulosic or other organic materials may, when arced, produce gaseous mixtures which are moderately flammable. As a precaution, such gases should be removed from the askarel by bubbling dry nitrogen through the askarel and flushing the gas space with dry nitrogen before any work is performed on the apparatus. VIII. Avoid Environmental Pollution Transformer askarels contain polychlorinated biphenyls fPCBs) which have been used in the United States and elsewhere over the past 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 and that they can have adverse ecological and toxicological effects. The United States Government's Interdepartmental Task Force on PCBs, Com-72-iW19, in their March 20, 1972 report titled, "Polychlorinated Biphenyls and die Environment", recommended restricting PCBs to use in capacitors and transformers. This report is distributed by the National Technical information Service, U.S. Department of Commerce, Springfield, Virginia 22151. A document titled, ?Guidelines for Handling and Disposal of Capacitor end Transformer Crade Askarels, Containing Polychlorinated Biphenyls", .has been prepared and is available from the American National Standards Institute, Committee C107, 155 East 44th Street, . New York,New Yoric 10017.' . The scope, objectives and the composition of this committee are; ; ANSI Committee C107 . Scope:.'.', . ".v . \. : '* Procedures and guides for safe use, maintenance and disposal of , askarel and askarel-soaked materials used in electrical equipment. Objectives: .;. .< \ 1. Source of technical information and advice for Federal, State, local authorities and ell others concerned. , 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, 1EC..CIGRE. TOWOLDMONOQ29083 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 lor Testing and Materials; Electric Light and Power Association; Certified Ballast Manufacturers Association; Environmental protection Agency; Office of Environmental Affairs; General Services Administration; National Bureau of Standards; Department of the Army; Rural Electrification Administration; Division t Environmental Research, TVA; American Public Power Association, Water Pollution Control Federation; Food and Drug Administration; National File Protection Association; Underwriters Laboratories; and several sections of tire U.S. Department of Interior. The following are pertinent excerpts taken from the ANSI Guidelines foi askarel transformers: 1. LABELING ASKAREL TRANSFORMERS "All new askarel transformers should be labeled: Caution The Insulating Liquid In This Transformer Contains Polychlorinated Biphenyls (PCBs). Care Should Be Taken To Prevent Entry Into The Environment. In Case Of Malfunction Or Leaks, Consult The Instruction Manual Or The Manu- . lecturer, , The transformer manufacturer should make similar warning labels available for use on previously installed transformers." 2. DISPOSAL OF LIQUID AND SOLID WASTES "Disposal of askarel fluid and askarel-soaked materials must be accomplished by means in which there is no significant release of askarel to the environment. At present, disposal is accomplished by carefully controlled high temperature incineration of liquids and soaked software; and by controlled dry landfill burial of apparatus and other hardware from which askarel has been previously drained and washed. '. . "Present knowledge indicates that proper incineration Should involve a suitable batanoe between dwell time and temperature in the incinerator plus oxygen availability and finally suitable scrubbers to remove HC1 formed; e.fl., 01 twosecond dwell time at approximately 2000 F and 3% excess oxygen in stack gas; (21 1-1 Vz second dwell time at 2700eF and 2% exoess oxygen m stack gas." v < The ANSI Guide lists the locations of facilities that conform with the above requirements. Monsanto has such en incinerator at the W. G. krumrririoh Plant, 'Department A-246, Sauget, Illinois 62201, where arrangements can be made for scrap askarel liquid disposal for a modest fee, currently 3 cents per pound. 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 Conditioning of new askarel or recycled askarel requires Fuller's earth treatment. The spent Fuller's earth m cartridges oi bags whon replaced should be allowed to thoroughly drain over dnp pans to remove as much liquid askarel e$ possible. The cartridge units of steel mesh construction should be placed in the "Steel Contaminated with Askarel" container for disposition. Cloth begs filled with Fuller's earth should be placed in the "Scrap Burnable Askarel Waste" container for disposition. . - : , ;  A. TEARDOWN OF TRANSFORMERS FOR REPAIR OR . SCRAP a. Drain all askarel from the unit either into a holding tank for reuse or into the dium labeled "Scrap Askarel" for disposition, then allow sufficient time for all the askarel .............. to drain from the core and coils. b. Remove the core and coil assembly from the transformer and place it on the floor. Sufficient absorbent material should be placed on the floor to absorb any askarel fluid that still drips from the transformer. c. Place all materials in the appropriate salvage containers during the dismantling for later disposition. d. All used materials, including rags, sawdust, tape, etc., regardless of quantity, should be put into the : appropriate containers for disposition. 5. TRANSFORMER DISPOSAL The ultimate disposal of an askarel-filled transformer may be accomplished in either of two ways. a.. Complete drainage and dismantling with the proper disposal of the askarel liquid and eskaret-soaked components as described above. b. Disposition of askarel transformers by means of junk or scrap dealers should be avoided unless a transformer is . first drained, followed by soaking of the interior with a suitable solvent, such as kerosene. Accumulated liquids and washings are to be disposed of as described earlier. IX. Expected Service Life Manufacturers indicate that properly designed and installed askarel transformers are expected to give trouble-free service for 8t least 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 rate for askarel transformers as 0.13 per hundred banks per year. Mr. Frank M. Clark, who invented transformer askarels at the General 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 have them atone". ,, These words of wisdom became especially applicable in more recent years When welding shut rather than gasketing became the main method of sealing askarel transformers. These units are sold with the understanding that the liquid is in a normally hermetically closed system, , X. General Characteristics of Transformer Askarel Fluid Appreciation of the following characteristics, as given in the IEEE Guide, Jeads 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 materia); i*., to molecules are dipoles, free to rotate around their axes and responsive to orientation by electrical forces. Askarel also exhibits a much higher dielectric constant and capacitance than insulating oil, and these differences must be kept in mind when interpreting electrical test data. > Because ft is relatively polar, and possesses high solvency power, askarel is much more electrically sensitive than mineral oil to traces of extraneous soluble polar materials, and consequently die choice of i I 0763698 rnmmmmsm TOWOLDMONOQ29085 constructional materials destined for use in askarel is very critical. This sensitivity is reflected in the power factor and resistivity (specific resistance) of the askarel. It is important to note that, with the exception of water, the dielectric breakdown voltage of askarel is not generally adversely affected by many of the soluble polar materials to which its power factor 8r>d resistivity (specific resistance) are so sensitive. In fact, the dielectric breakdown voltage of askarel is somewhat greater than that of insulating oil. Therefore, the values assigned these dielectric fluids in newly supplied transformers are 30 KV min. and 26 KV min., respectively. .. As with insulating oil, askarel must be kept dry. it can pick up moisture from exposure to humid atmosphere. Under similar conditions of exposure, askarel can pick up nearly twice aS much moisture when measured on a parts per million weight basis. . . XI. Sampling Transformer Askarel Fluid The following precautions about sampling are quoted from the IEEE Guide. , "Representative samples, whether of the complete contents or only parts thereof, are extremely important from the standpoint of evaluation of the quality of the product sampled. Obviously careless sampling procedure or contamination in the sampling equipment wilt 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 Electricallnsulating 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 surfaoe. The top sample, therefore, is considered to represent the worst condition." XII. Evaluation of Askarel Received in New Equipment Some users of askarel equipment find it desirable to make "as received Jests" on all equipment, ft is quite common to use the dielectric txeakdown voltage test and visual appearance as the most significant tests, ff suitable equipment and trained personnel are available . additional information may be obtained from the power factor, color, end moisture content tests. : , ... In sampling askarel contained In apparatus extreme care must foe exercised in order to obtain a representative sample. ASTM Method 0 923 should be fpllowed. . >, New equipment with askarel exhibiting the following characteristics is ii considered acceptable: v |ji 4 , , :ji Dielectric Breakdown Voltage 30 KV min. , ASTM Methods D 877 Color 300 max. (Straw color) D2129 Condition - Visual Water Content Clear 35 ppm max. / D 1702 . D 1533 Power Factor at 26* C * 0 924,0 ISO "The power factor of askarel taken from new transformers, reactors and accessory equipment pah reflect the ..presence of moisture, dissolved polar compounds, or other contaminants and. may vary with the type of equipment from which the sample was taken due to the different ratios of fiquid-to-solid insulation and to the high solvency power of the askarel. Given an acceptable water content and dielectric breakdown voltage of the askarel as indicated above, a high power factor seldom impairs the serviceability of the askarel within rather broad limits and 4s w TT TOWOLDMONOQ29086 r indicative of the degree of extraneous soluble polar mateiials present. Recognizing the possibility of a wide range of power factors being recorded for askarel in new equipment, it is difficult to establish a single limit which would be acceptable to both suppliers and users for all applications. However, as a broad guide, power factors up to about 10% at 25Cand 60 cycles per second (hertz) do not in general indicate any abnormal contamination providing that the other criteria (water content, dielectric breakdown voltage, etc.) are met. Much higher power factors may indicate excessive contamination or the misapplication of the solid materials used in manufacture in contact with the askarel and 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 voltage can also be lowered by severe arcing, askarel turns noticeably blaok or has particles of sooty carbon floating in it if arcing has occurred. Then the transformer should be repaired and the askarel replaced. if tire dielectric breakdown voltage is checked periodically and decreases significantly -- this indicates moisture pick-up, arcing, 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 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 is found to be in a satisfactory range and the dielectric breakdown voltage is low, the transformer manufacturer should be consulted. Table JV shows the relationship of dielectric breakdown voltage vs. fnoistqre and Table V indicates the approximate water solubility limits in askarel and mineral oil. Table tV Relation of Dielectric Breakdown Voltage to Amount of Dissolved Water in Askarel and Mineral Oil Water Content (PPMj , Breakdown Voltage (ASTM D877) . Askarel Mineral Oil 0 20 .\ 60 80 110 70 KV 50 KV 55 39 ... 47 30 , o . . 26 38 2? 10 6 TOWOLDMONOQ29087 Table V Approximate Solubility of Water in Transformer Askarel and Mineral Oil 5, !L Amount of Water (PPM) Dissolved Mineral Oil 30 -22 20 A -10 14 0 32 10 60 20 68 30 86 40 104 8 16 28 41 65 94 128 170 8 10 13 20 33 68 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 15*F above zero. To redissolve it requires heating to 150-200"F and agitation. High dielectric breakdown voltage will quickly indicate that any turbidity present is not moisture; that the insulating efficiency of the askarel is still excellent. However, if the dielectric strength is below 26 KV, moisture should be determined, using the Karl Fischer method (ASTM 01533-60). \ The dielectric breakdown voltage test for askarel serves primarily as an indicator for moisture. It is by far the most important maintenance test for transformer askarel. XV. Checkpoints for Maintaining Askarel Insulation A. Gonoral Considerations: s , Modern askarel transformers with welded construction or silicone or Viton* gaskets (hand hole-cover, switch and terminal compartment covers) and with properly constructed bushings require little 01 no maintenance. With properly constructed transformers, annual or semi-annual visual inspection end, dielectric breakdown voltage test of the askarel fluid should suffice foT routine maintenance checking over many years of service. However, many askarel units were installed in the early 1930s before the development of some Df the better modern gasketing materials and before improved designs were developed for sealing out moisture. $uch early units should be, and can be, modernized, leaky or deteriorated gaskets should be replaced. If the askarel has become contaminated, it should be reconditioned. At the same time, a general clean-up of the unit and possible refinishipg may be desirable. ,, - If it is not convenient to take an old transformer out of service for general repairs, leaky gaskets can be scaled temporarily by painting over the leaky aroa with epoxy cement, A survey of users indicates e good number of arly-buill askarel transformers (over 20 years old) are kept m continuous service in critical installations by the following steps finstead of modernisation). The operating units are equipped with compound pressure gauges lot reading pressure above and below atmospheric. Positive Trademark ol C. I. DuPom DofJomoun & Company. Jnc. pressure is 'maintained on the shell by introducing nitrogen at 2 to 3 pounds above atmospheric. Regular workmen in the area daily record the temperature and pressure, If a sudden pressure drop is noted more nitrogen is introduced and the gaskets are checked for teaks with,soap solution. Leaks are sealed by applying epoxy cement. 6. 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 tank wall) a. Cast resin bushing with a molded seal to the bushing stud and external stainless steel or copper > -. flanges. b. Rolled flange bushing with the metal to porcelain seal at the cap and flange made by being rolled into grooves in the porcelain over silicone rubber rings. The seal between the cap and stud is made by ' ` welding. c. Porcelain or glass bushings with metal to glass or . ` metal to porcelain seals. 21 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-nitrite rubber combinations or nitrile rubber as well as gasket materials such as silicone or Viton. 3, Small Size Connections: When not possible to weld, small size connection seals should be made with flexitallic* stainless steel rings. The surfaces must be machined and parallel. The filler between the steel laminations of the ftexitallic ring should be either silicone or Viton. 4. Gaskets for Hand-Hole Covers: Modern design specified silicone gaskets. Such gaskets must be retained in a groove. The groove preferably is machined into the flange or cover. However, it can also be formed by welding concentric steel strips to the flange or the cover. Generally the gaskets should be 6/16 to 1/2 in. thick 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. 60 Silastic** or equivalent. This is a low compression set material. 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 care the gasket is removable without damage and is reuseable. Silastic 60 is slightly swelled by askarel which contributes to the tightness of the seal. It is not deteriorated by askarel fluid or vapors, it resists weathering and it is thermally stable and Trademark of Tiexitallic Gasket Company Trademerkol Dow Corning 1 11 TOWOLDMONOQ29089 p!.i Ililh T? i1:f1 flexible at all operating temperatures, ft is an excellent moisture barrier. .' NOTE: Dow Corning, Midland, Michigan will supply a list pf Silastic 50 flasket fabricators to all transformer manufacturers or users. They will also furnish technical data. See Appendix K: Seals* Properties and Procurements. C. 1 he Older Sealing Arrangements: . ' The older type flaskets consist of either cork or cork-nitrile rubber combinations or straight nitrile rubber. I. Cork-Nitrile Combinations: Covers for 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 Shellac (Westinghouse Style No. 1150419, or General Electric Company's Glyptel* 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 mater ial. 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 B614 G01, fabout $15). The joints - and also the gasket - should be oemented to the flange, using one of the above cements. Excess cement should not be allowed to reach the Interior of the transformer. Alter installation and bolting, the outside edge of the gasket should be coated thoroughly with epoxy cement to increase weather resistance. . This epoxy cement is a paste to which a curing catalyst is added immediately before use. Typical are: - a. Epoxy Patch Kit : Hysol Corporation, Olean, New York , . , b. Scotchcast** * Resin #4 . Minnesota Mining & Manufacturing Company St. Paul, Minnesota c. Adhesive A1 and Activator Type B Armstrong Products Company Argonne Road, Warsaw, Indiana - i d. Adhesive 0860-1, Synthetics `Organic Company, Cleveland, Ohio, used with activator diethylene friamine (Carbide and Carbon Chemical Company) < 2. Straight Nitrile Rubber: When straight nitrile rubber was originally used, invariably the gasket was recessed in a groove. This was to prevent gasket flow and to protect the material against excessive compression. Although this type seal was not cemented, the nitrile rubber gasket is not reuseable.; Since grooves or stops have already been provided tor the nitrile rubber seal. Silastic SO can be easily substituted and is recommended. This conforms with modern practice. XVI. Periodic Rluid inspection and What Checkpoints Mean On a regular schedule -- at six, nine, or twelve-month intervals - make a simple visual inspection of your eskarel insulation and run a dielectric breakdown voltage cheok. 1 trademark of GenetVElectricCompany' , ;l ' - . . ... , . , Trademark pf MinnewtaMinios^ Manufacturing Company;; . : j0?63 703 TOWOLDMON0029090 A. Visual Inspection: Askarel is a clear, taint-yellow liquid. After long-term use this color may gradually intensify to light brown. The fluid should remain clear and free from turbidity or cloudiness. Any color change -- such as to a green, red or blue cast - indicates extraction of impurities {color materials) from the solid insulation. If e distinct foreign color pick-up is noted, check the complete range of electrical characteristics and notify the transformer . maker. Blackening of the askarel may indicate an arcing condition. Other color changes alone are not danger signals since the dielectric breakdown voltage is not likely to be impaired. B. Dielectric Breakdown Voltage If the dielectric breakdown voltage has decreased significantly from the last inspection, or if it has gradually decreased below 26 . KV range fat 25C) - RUN A CHECK FOR MOISTURE. Use ASTM D1533 {Karl f ischer Method). The dielectric breakdown voltage of askarel is the major indicator to the pperating efficiency of your liquid insulation. Besides the visual inspection tests, dielectric breakdown voltage is the only test necessary to run on a routine basis. Well-sealed askarel transformers have service records of 25 to 30 years on the original askarel. XVII. Inspection Checklist 1. If askarel is clear - even though darkened to light brown, has no . sediment or turbidity, has dielectric breakdown voltage over 26 KV-- give it the inspection "OK". 2. If askarel is clear, but has foreign color of blue, green, red ... it is "extracting color" from internal materials. This is not, of itself, an operating hazard when the dielectric breakdown voltage stays over 26 KV and moisture remains low. However, this rare occurrence calls for checking into the condition of the interior construction , and consulting the transformer maker. However, when sampling the fluid care should be taken to avoid getting color into the askarel from paint that may be inside or outside of the sample valve. 3. If the moisture content is found to be above 70 ppm at operating temperature, then sampling should be done at more frequent ' Intervals to establish a possible trend, particularly on outdoor -installations. , 4. If askarel isclear, but dielectric breakdown voltage drops to 22 or tower KV. and moisture rises over 80 ppm when sampled at operating temperature ... the askarel is ready for simple ''refining". If the moisture is near the saturation level (about 125 ppm at room temperature) a thorough inspection should be made for water droplets in the transformer tank, and even for 'folobules" of .water floating on the askarel surfaoe. If found, the transformer manufacturer should be consulted for reconditioning both the transformer and the fluid. 5. If askarel ts dark brown to black, if black particles of carbon are seen, and dielectric strength is tow ... the askarel has been broken down by arcing. It cannot be refined and should be removed and Incinerated under proper conditions. (See ANSI Committee C107 report on Use and Disposal of Askarel and Askarel Soaked Materials. 116 test 44th Street, New York, New York 10017). - *If any of these five simple inspection tests appear out of the ordinary or the relationship between appearance and test values is abnormal, contact your transformer supplier for a complete analysis. - . "Whenever a sample is to be shipped to Monsanto, please follow the directions shown under: "SAMPLING ASKARE L". 0263704 TOWOLDMONOQ29091 XVIII. Contamination in Transformers Moisture, particulate matter and arced decomposition products are known to be serious contaminating influences on transformer askare!. The power factor test normally used for the detection of contamination In mineral oil filled transformers is of little use for this purpose in askaret filled transformers, due to the extreme effect of extraneous soluble polar materials. This increase 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 96 Hours in Askarel at 100"C.I Material Immersed AskareljAfter Exposure Power Factor, Percent at 60 eye., 100C Dielectric Strength 25*C. None (control) Black varnished cloth Copper Pressboard Manila paper Phenol formaldehyde resins Shellac Iron Synthetic rubber 1.0 85.0 1.6 2.0 1.6 1.6 6.0 6.0 70.0 36 KV 42 40 37 39 41 36 39 39 Similarly, trace contaminants from commonly used construction materials can lower the volume-resistivity of askarel, without affecting its dielectric breakdown voltage. This is shown in Table VII. Table VII Effect of Common Insulation Materials on Volume Resistivity of Askarel . : : ft Sample Volume Resistivity x 109 ohm-cm fat 100"C,, 600 Volts 7 DC., 0.1 "gap) 1. New askarel before heat aging 2. New askarel after heat aging 96 hours at 100 3- After heat aging with 1 sq. inch specimens of: a. Phenolic resin tap changer material b. Paper . c. Grade A piessboard (ten) d. Grade A pressboard (gray) e. Grade A pressboard, laminated strip 1. Cotton wrapping sGlyptal 1276 cement, cured 48 hrs. at 110*C 2,000 1,900 1200 750 600 600 400 300 100 While trace contamination easily lowers volume resistivity from high levels, it Is important to note that heavy contamination (as when arced) does not lower the resistivity below the order of 109 bm-envat 100"C. The different behavior of askarel ys. mineral oil in these respects can be summarized as follows: ', . . ; : ./ High powor factor and low volume resistivity in transformer mineral oils are commonly regarded as 'danger signals'* that the oil has deteriorated and broken down chemically r excessive moisture is present. >. : ... ; . , This is NOT TRUE of askarel liquid insulation unless the dielectric breakdown voltage is low or the moisture content is high. / V iv ^ ' ' ft'" ,. Manufacturers of askerel type transformers point out that it is quite weft known that askarel transformers with initial power factor of the askerel fluid in excess of 0% at room temperature and 60 Hr are giving satisfactory service tife. However, there needs to be assurance that both dielectric breakdown voltage and moisture are at satisfactory levels and do not show adverse trends. . XIX. ASTM Method For Investigating The Compatibility of Transformer Insulation and Construction Materials in Askarels .1, =:1 - This method2 uses the change of elecincal and/or chemical characteristics of transformer askarel resulting from its controlled exposure to insulation and construction materials, in order to evaluate their immediate major "contamination" effect on the askarel fluid. Delayed or long time contamination affects may not be detected. The .method also utilizes various physical tests on the insulation and construction materials after controlled exposure to the askarel to determine the compatibility of these materials with transformer askarel. Properly proportioned specimens of the insulation or structural materials are immersed In refined askarel for 168 hours at 1001 1*C in a forced draft oven. Changes in electrical and chemical properties of the transformer askarel are compared against a control sample of the askarel treated in the same manner, in absence of the test specimens. Dissipation factor fASTM D 024) change is one of the criteria used. *1 he askarel fluid is refined by absorptive treatment to a dissipation factor level of 0.05 max. at 100C and 60 Hz and 0.01 m&x. at ?5*C and 60 Hz. Corresponding values of the askarel fluid after heating 168 hours at 100*C in aibsenpe of a lest specimen are 0.075 and 0.02 respectively. The maximum dissipation factor levels suggested for the askarel after heating in presence of the test specimen are 0.20 at 1Q0C and 60 Hz end 004 at end 60ta. * < H- XX. ReTmingAskarel for Reuse * 1 , A. Fift<?i*ng Through Dry Blotter Paper to Remove Moisture and ,<* Extraneoustterticto. - Moat Operators prefer portable refining apparatus, such as a plate L:".press fitted with a dolly, .available from Sparkler, Mundelein, ' fa - Illinois or fteneraj Electric Company, Pittsfield, Massachusetts, or ^ 1 ) jtiarjfyeft cartridge filter type available from Industrial Filter Corporation; Xebanon, Indiana. Filler paper liners for the plate press ate available from Carl Schleicher and Schuell Company, Keane, -New^Hampshire and manufacturers of filter presses listed \#< yThe fitter paper must be dried immediately before use. For best 1 spread (the paper for maximum surface exposure in a hot sffA Matndfipdlating oven end heat ti for 4 to 6 hours at 110V. . N . , Circulate 1be askarel hpt (bjit not over 4(70 through the filter ' fitted w'rthjhe dry paper liner*, ' 'Vu* After ^Hredon fhe dielectric breakdown voltage of the askerel Should te 35 KV minimum , * *j| f*l s * * ^ - 1 jJH. 'FVecautiphr Tilierine should not be done when the relative X" '9umidityifKooadsTS% '** < J : ' Ahy flexible hoses And gaskets on the refining equipment >>1t y jdjhhbiiffttdd.,bbe lifted with or made of materials that will not be , fluid I{Mastteerriatjls fined with ..... i ihate/'laH ire f! !.1 .;i; :i 1 i :1 m0P' % A* dfpublication by ASTM,*! dt fhli writing u. . S N a * t I DumontJD^emount & Compiny, Inc TOWOLDMONOQ29093 Table VIII Guide to Rate of Dissolved Water Removal 8y Filtering Askarel Through a Paper Press Passes Through Paper Press 0 1 2 3 4 6 Water in Askarel ___ PPM _____ 115 35 22 18 12 10 io Disposal of Solid Wastes: The ANSI Guide stales that, "All Solid wastes which have been saturated with askarel should be disposed of by the following procedure: 1. The saturated wastes should be placed into leak-proof containers and transported to a supervised dry landfill site meeting State requirements. Alternatively, they can be disposed of by incineration in State-approved facilities. 2. Solid absorbents used for spills can t>e disposed of uncontalned In the supervised dry landfill site; transport to the site should be in closed containers. Alternatively, incineration can be used in accordance with par. 8 (See Section 4 for facilities)/' ` Solid Insulation Requiring Drying: . If the solid insulation of the transformer requires drying, consult the transformer manufacturer or an apparatus service shop, as in such case oven drying is preferred. Earth Treatment for Maximum improvement of Power factor and Volume Resistivity: We question whether pumping and filtering the fluid solely to achieve a change in power factor or volume resistivity alone is justified in today's ecological climate regarding PCBs. We *j reoommend that in these situations the Original transformer manufacturer be contacted. < ,: \ y' I 1. Procedure: The askarel liquid should be relatively dry prior to the following earth filtration. . At a coating on the filter paper surface use finely divided Attapulgus clay or Fuller's earth dried and activated by heating for 12 hours at 300-350T immediately prior to use. The amount of earth used should be 0.1 to 0.2 percent by weight on the weight of the askarel to be treated. Askarel weighs about 12.6 pounds per gallon. , .. . To deposit the earth evenly, stir one-third of the earth with a small portion of askarel in a clean container. Pump the mixture through the filter and follow with two more one-third portions. Then circulate askarel taken from hear the top of the transformer, pass it warm foot oyer 65C) through the earth-ooated filter and feed back through the bottom transformer outlet. Continue circulation until the fluid is clear and test shows that the electrical properties are fully restored. , 2. Effect of Earth on Removal of Scavengers Only slight and insignificant loss by selective absorption of tin tctraphenyl and epoxides occurs when askarel isrefined . by treatment with 0.1 to 0.2 percent by weight of earth. To remove significant amounts of the scavengers requires repetitious treatment with much larger amounts of earth. O763707 3 TOWOLDMONOQ29094 Table IX Approximate Relationship Showing the Insignificant Effect of Power Factor and Volume-Resistivity on Dielectric Breakdown Voltage of Transformer Askarel Power Factor (60 eye.) TtoHT........ ....... ?s-C Volume Resistivity x 10 ohm-cm (at 100*C, 500 Volts DC. 0.1" nap) Breakdown Voltage 25C, 0.1'' gap 2% 55% 15% 20-25% 40-50% 0.05% 0.1% 0.7% 2.0% -- 1500 500 100 6070 25 35 KV 35 35 35 35 XXI. Cleaning Arced Transformers If a unit has arced so that the askarel is no longer fit for use, a thorough cleaning of the unit is necessary before refilling with new askarel insulation and returning it to servioe*. follow this procedure: A. Drain out all dark, carbon-contaminated askarel. Arrange to have the scrap fluid incinerated under proper conditions. (Sec ANSI Committee C107 report.l B. Carefully brush carbon deposits from internal parts and insulation, using a soft bristle brush making sure that insulation is not damaged. C. f lush thoroughly using new askarel -- not an oil, not a cleaning solvent. 0. flush a second time with fresh askarel; drain; then fill to the proper level with new askarel. E. Energize transformer to warm the fluid for 24 to 48 hours; then circulate the askarel through a fitter, returning it to die unit filtered and ready for use. This assumes that the cause of arcing has been established and corrections made. When severe arcing occurs, major repairs ere usually necessary end the unit rebuilt. This procedure can be applied for flushing out the repaired units. XXII. Sampling Askarel Take a sample as close to the top of the liquid surface as possible. Many large askarel transformers have a built-in sampling tube near the surface for convenient sampling. Then, to make sure that your sample truly represents your askarel insulation, take another sample from the bottom. If additional sampling tube connections are contrived on the valves for easier sampling, make the tubes of clean glass, stainless steel, aluminum or tin for rigid types; and silicone, or Viton or Teflon tubing for flexible types. - . Use NEW containers for the askarel sample. A new and thoroughly pre-dried,small-mouth quart glass bottle fitted with a Baketite* screw cap with aluminum or tin cap liner Is recommended for quick, on-site testing. Of complete analysis is to be made, a 5-pint size sample is required.) Be sure that the new bottle does not stand open to collect dust or moisture. Rinse the sample bottle and cap lining two or three times with askarel from the transformer, then fill it. If the sample will be tested promptly, a clear glass bottle can be used. If sample is to be stored indefinitely, use an amber glass bottle or wrap clear glass with aluminum foil................ - , A, Select a dry day. Do not sample insulation on a warm, moist day when humidity exceeds 75%, and... ;*Trdemark of DnlonDaibKle Corporation . ' . f637oH 3 TOWOLDMON0029095 8. Make Hire that the askarel is at least as warm as the surrounding air. (Cold liquids can condense moisture from humid air.) C. When sampling askarel from transformers, it is best to take the sample when the unit is warm and operating at average or maximum load, especially for a check on moisture as reflected by 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. i 0?<>'3 70` ) TOWOLDMONOQ29096 ? S(gtlfi(o)m ]I3 Askarcl Filled Snitches and Terminal Chambers 1. Introduction High voltage leads are usually connected to askarel or mineral oil-filled network transformers and power centers through terminal chambers and switches, fn 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. Switches are usually rotary or drum type fitted with a revolving block and porcelain unit as the principal element arranged for three-phase service. Askarel transformers with attached switches have been in use for about 30 years. When they were first introduced, the availability of insulating and gasketing materials was rather limited and even the best materials at the time had no service history. As a result, inadequate gasketing materials such as cork, nitrile rubber, and nitrile rubber-and cork particles were used. While satisfactory for a limited period of time, these materials cannot be depended upon for the expected long life of the equipment. The terminal chamber is usually above or below the switch compartment and separated by a steel wall through which the bushings are inserted. When bushings are' properly selected and correctly installed, there is no leakage from one compartment to the other. With poor bushing seals, and the terminal chamber above the switch, potting compounds or cable oil can seep into the askarel. When the terminal chamber is below the switch, askarel can drain into the terminal chamber. . II. Sources of Contamination There are three possible sources of contamination for askarel in switches and terminal chambers; they rank in this order of frequency: O) water entering through poor gaskets; (2) decomposition products from arcing when switch is used to break magnetizing current; <3> entranoe of pothead or cable compounds through leaky bushing seals. Unlike an askarel transformer where the amount of contaminant is likely to be very small (probably only trace amounts) in relation to the volume of askarel fluid -- in switches or terminal chambers with faulty seals, the amount of contamination can be relatively large. Experience has hown that, based on the number of installed askarel-switch units, the percentage of failures is extremely small. When investigated, it has been found that most failures originate in the switch chamber, Water is the chief source of contamination. However, heavy contamination of askarel with petrolatum and asphalt material, due to leakage, have caused a few failures. Petrolatum is used frequently for filling terminal chambers. When either cable oil or petrolatum seeps into askarel, no great harm results. The hre resistance will bo somewhat decreased and power factor of the askarel will increase with an accompanying drop in resistivity. While highly undesirable, it is doubtful that failure of the unit results. Where asphaltic compounds are used in place of petrolatum, the danger is increased somewhat because asphaltic contamination may cause excessively high dielectric losses in the askarel. When the terminal chamber is below the switch chamber, the potting compound can be contaminated by askarel if the bushing seals are icaky. This is undesirable because the askarel will increase the power factor and conductivity of the potting compound or cable oil and develop heat from dielectric loss, if this mixture is drawn into the cable 0?fe^10 TOWOLDMONOQ29097 insulation, a cable failure is likely. This again emphasizes the importance of tight bushing assemblies. Ifl. Sealing Switches and Terminal Chambers Pioper bushing construction, use of Silastic seals and welding wherever possible is highly desirable (as covered in Section A). Where an elastomeric seal is to be used in contact with both askarel and petroleum oil, DuPont's Viton is suggested. For new equipment the user should specify these modern sealing arrangements to keep out contaminants and minimize maintenance. IV. Askarel Used Under Mild Arcing Conditions The IEEE Guide for Transformer Askarel calls attention to the following: . . "Askarel bused, 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 that when askarel is used under these conditions, checks of the liquid, especially for moisture and dielectric breakdown voltage made more frequently then 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. 8. Switches interrupting magnetizing current will be subject to arcing; the amount of decomposition will depend on power interrupted, time and frequency of operation. As a general rule, the liquid should be checked after 5 to 10 operations. 1. On newly installed switches, check the askarel at 3, B and 12 month intervals; if found satisfactory, check onoe annually thereafter. With proper attention to the gasketing of covers and bushings, experience will probably indicate that less frequent inspection is warranted. 2. Check askarel for: `` a. Dielectric breakdown voltage (ASTM D877); It should be 26 KV minimum. If 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 carbon. If badly arced and very black, replace fluid. If only minute amounts of carbon are present, filtration is recommended. Check power factor of liquid (should not be over S% at 25C and 60 cycles). Flush out switch chamber with several gallons of fresh askarel before refilling. - 3. If there is discoloration, high power factor, detectable change in specific gravity or refractive index, or if fluid flashes below 25CPF, there is a possibility of seepage of potting compound into the switch compartment. Jn this case, correct any leaky bushing seals with proper replacements and fill with new askarel. . ' \ ' ' "y'.> - 4. If terminal chamber is below switch. Check potting compound for presence of askarel .(can usually be detected by odor or by an increase in specific gravity). If askarel is present, correct Any leaky bushirg seals with proper replacements, and renew compounds. *6. Examine cover gaskets visually. Deterioration can be detected , . , - ' , . 1. , , ., . . . . , . ;, . 1 j * : , TOWOLDMONOQ29098 by swelling and cracking of the exposed edge. In cases of severe deterioration, liquid seepage Is usually present. 6. Check for leakage at packing gland of switching shaft. If leaking, repack with a Silastic ring type gasket. VI. Askarel Under Excessive Temperature or Fault Conditions The IEEE Guide also points out that, "Chlorobenzenes used in transformer askarels begin to boil at temperatures of about 205C, 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 askaret-filled equipment be provided with pressure relief devices. These devices must be large enough to provide immediate relief at a definite pressure, and to prevent further build up of pressure 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." Analytical Services on Transformer Askarel Available From Monsanto Transformer users not wishing to make their own fluid analyses can obtain the service from Monsanto. Simply contact Monsanto and specify what analyses are wanted. You will be sent the proper-sized, clean sample container, fitted with a proper label. When you receive this, carefully take your sample (following the procedure for sampling in this guide). Send the container to Monsanto's laboratory. Charges listed include sample container, shipping, handling and laboratory costs. Types of Analyses Available ., Analysis 1) V ROUTINE MAINTENANCE CHECK , v'''\ Total Charge: $25.00 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 ?) COMPLETE ANALYSIS Total Charge: $55.00 (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. a) Complete Analysis: to determine the extent of contamination Pioperties Tested Free Chlorides ' Color and Condition , , .. Acidity . Specific Gravity Dielectric Breakdown Voltage ' Refractive Index . Power Factor, Dielectric Constant, and Resistivity Water . . . b) Earth Refinement Response: ' .. Consists of treatment for 2.5 hours at 50-60C. with 0.1 to 0.2 peroent by weight of properly conditioned Attapulgus clay and then filiation throughdry filter paper. c) Analysis After Laboratory Earth Refinement: Pi operties Tested Acidity........... Refractive Index Dielectric Breakdown Voltage Water Power Factor, Dielectric Constant, and Resistivity Free Chlorides . You will be notified of the results of this test series on your sample. Then after refining your entire transformer fluid fill you can chock on the results by requesting the following analysis: - > Analysis 3) ANALYSIS AFTER EARTH REFINEMENT Total Charge: $35.00 ,. (This charge will not apply when . analyses 1 and 2 have already been made,f , To determine whether the entire lot of the askarel fill responded to the same extent as the laboratory sample, (five-pint sample required) ; ` ,. . Properties Tested Free Chlorides . \ Color and Condition Acidity / Refractive Index Dielectric Breakdown Voltage Water , Power Factor, Dielectric Constant, and Resistivity To arrange for the tests described above write to the following address: ' Paul G. Benignus , , Monsanto Company 'i - ., > 600 North Lindbergh Blvd. . - r St. Louis, Missouri 63166 ' . , . "Samples to be tested should be clearly marked for identification and sent directly to: Monsanto Chemical Company W.G. Krurnmnch Laboratory . < ,4 ' Sauget. Illinois 62201 / Attention: R. Kuster - , . : 0?bT/IT ) TOWOLDMONOQ29100 APPEND1X A ____________________________ Atkatc! Stability and Composition of Arc formed Gas: Askarel insulation is one of the most inert, chemically-stable heat resistant, non-corrosive liquids known. It will not break down, oxidize or sludge when exposed to air and high temperatures, 1&0"C. or even somewhat higher. Arcing, however, will break down the compound to liberate some hydrogen chloride and imall amounts of carbon. ., . . . APPROXIMATE COMPOSITION ARC-FORMED GAS FROM TRANSFORMER ASKAREL BLENDS ASTM TYPES D AND G (INERTEEN 70-30 AND PYRANOL A13B3B-3, RESPECTIVELY) Gas c~a~rbon monoxide carbon dioxide oxygen inert gases \ V; hydrogen chloride (note the absence of phosgene) . Amount 0.3% 0.3% 0.6% 1.6% 97.3% This arc-formed gas from ASTM Type D and Type F transformer askarels is non flammable and non-combustible. For all practical purposes, the amount of gas liberated from askarel under a given set of arcing conditions is about 100 cubic centimeters per kilowatt-second. , .. ! APPENDIX B APPENDIX C SOLUBILITY OF GAS IN TRANSFORMER ASKARELS ASTM TYPES D AND G ' Carbon dioxide Air Nitrogen Hydrogen chloride1 Mn absenoe of scavenger :' Percent of Gas By Volume Corrected to: 25X2 760 mm, 0C. 760 mm 25C 71% 6.7 e.o 37.6 10CPC 47% 4.9 AJd 60.9 26-C ' -- 66 6.6 . : ", - ' 100-C 6.0 4.4 EFFECT OF TEMPERATURE ON DIELECTRIC BREAKDOWN VOLTAGE OF ASKAREL Temperature *C ~ -60 ~ -40 -20 0 20 , 40 , 60 60 Dielectric Breakdown Voltage __ ASTM_D_877 63 67 ' 65 60 60 48 45 . ' ., .! 0?<371i TOWOLDMONOQ29101 APPENDIX O COMPARISON OF THE APPROXIMATE VISCOSITY IN SAYBOLT UNIVERSAL SECONDS OF TRANSFORMER ASKARELS AND MINERAL OIL . ., ' Temp.^d -20 D 20 40 60 BO 100 *' ,. ' . , -. ' , fVrancrt = A13B38-3 . ' ` ' 1,000 100 70 45 39 ' 34 30, . ' ' , tDC Mineral Oil ' 1,000 ISO 85 49 TO 34 30 , , , ' Inerteen 70 30 2A00 195 85 50 40 . 36 , 33 APPENDIXE'" v -t ^ 1 V^/i# Mi* <- ` it', s t ' THE DENSITY OF INERTEEN 70-30 * AND TRANSFORMER PYRANOL A13B3B-3 Approx. Density gm/cxj,, . '` ' Temp, at '' sr". `i., > ' SO >, a? ,, 40 `s'.-r. BO '* RO'-^ K.-fo, . Inerteen ; 7030 - ' ~1J574 , , 1.652 *, 129 .' 1,607 ' r 1.465 , . / , , Pyrene! A13B3B3 1^77 1656 1632 1610 1488 ' ^'/* APPENDIX F The thermal conductivity vetoes t Transformer Pyranol A1383B3 at 21C end 68"C ere 283 end 258 x 10"* calories Centimeters1, degrees centigrade-1, second1. respectiva)y.lO(, approximately 0.06 BTU per IhrJ (tq. *t.| (T.I per loot. This seme approximation applies to Inerteen 70 90. 'rv ............ .v,.',... ,t'V APPENDIX G , ,> A sf f * Heet Capacity TT" -, tr '5,<w ' ,, Over the temperature range of 26* So 12SC the ^pe^IrcTneet bf transformer askerel k dote to 0-30 calories per gram per degree, i ' / * i,, i , \ 1 -.`t * AwPrPcEnNiwDiIAX Hn Mi' ,,, - The average.. gallon Would 1i APPENDIX I rr-?>.--..... ...... .. rj* V -.rwiivv die tempereture range 20 to 10CPC is0.0007 oc/ocPC.One W.'' \ A'" V -r FireResistenoe -?i>J.( ,\* ' f Askerels of various OompositionSI types ere used. Tinder ardtng Conditions the gases produoed, while consisting of predominantly non-combuttibie hydrogen Chloride cnh yield varying amounts Of combustible gases depending upon the oskeret type. '',7 v* >\ _ Insulation systems Incorporating these askerels and oeqdkN^aV biher organic tneiandk may,When arced, produce gaseous mixtures which ere moderately flommeble. As apspcpJlillSlCauifigases should be mmoyed from the atkarel by bubbling dry nitrogen through The asVerei and fludiing the gas space withdry nitrogen before any work Isperformed on the apparatus. IML ' /V *' 5 Vr N* wU' 4' >V, .' ' `I IJ 4kf FJ.^'nr.-A t >: -. 0263715 '-if - ^ ; , TOWOLDMONOQ291 02 APPENDIX J Seals, Properties end Piocurement Dow Corning Corporation, Midland, Michigan with Districts at Atlanta, Boston, Chicago, Cleveland, Dallas, Los Angeles, New York City, Washington, D.C. and Toronto has available Bulletin 09 019, August 1962 entitled "Silastic Design Data". This lists the gasket fabricators throughout the country from whom the "Silastic 50" gasketing can be purchased in sheet, extrusions or molded shapes. Generally, Silastic 50 sheet goods are stocked by local die cutters, hence, could be generally purchased locally. Usually small quantities of gaskets are die cut. If larger quantities are needed, tools are made of the same type used to cut oilier elastomers. Where the gasket is extruded for fitting into a machined groove or between gasket stops, Dow Corning advises use of a starved 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 480F. SPECIFICATIONS* ASTM D676 ASTM D412 ASTM D412 ASTM D395 Color Specific Gravity at 77F Hardness, Shore A. Scale Tensile Strength, psi, min Elongation, percent, min Compression Set after 22 hrs at 300F, percent,max White 1.20i 0.02 45 to 60 BOO 250 30 *AI! physical properties measured on 0.075 inch thick samples molded 5 minutes at 240t'F, and oven cured 24 hours at 480F. APPENDIX K _________ __________________ _____________________ Caution Label The following or equivalent caution statements should be fixed on all containers of transformer askarels and the transformers themselves: This product contains Polychlorinated Biphenyls (PCBs). Care should be taken to prevent entry into the environment through spills, leakage, use, vaporisation, or disposal of liquid or containers. Avoid prolonged breathing of vapors or mists. Avoid contact with eyes or prolonged contact with skin. If skin contact occurs, remove by washing with soap and water. Following eye contact, flush with water. In case of spillage onto clothing, the clothing should be removed as soon as practical, skin washed, and clothing laundered. Monsanto MONSANTO INDUSTRIAL CHEMICALS COMPANY SPECIALTY PRODUCTS GROUP 800 N. LINDBERGH BLVD. ST. LOUIS. MISSOURI 63166 The inlormfltion horein regarding obtaining optimum results ftom askarel fluids in your transformer has been accumulated by Monsanto for over 40 years hom tire experience of makors and usots ot askarel transformers and it is believed will be helpful. Nothing herein Shalt be constfued as applying to other than askarel insulation. Data and maintenance suggestions herein do not apply to the other components ot the transformer. All operating and maintenance suggestions recommended by the manufacturer of the transformer should also tx' carefully followed. Because those maintenance directions apply only to the askarel insulation, Monsanto disclaims any liability for damage to property or injury to parsons arising from transformer operation. 0263716 ) TOWOLDMONOQ29103 CUSTOMER SERVICE CENTERS AKRON, OHIO 44313 2$0 Springstdo Drive , Montroso Developmant P+rk Tel. (216)666-4111 , ATLANTA. GEORGIA 30339 320 Interstate North Parkway . Suit* 600 To! (404) 432-71114 , *, BOSTOK MASSACHUSETTS 02149 EverettStation - : :-- -. Jot. ($17)387 5010 CHICAGO,, ILLINOIS 3158 Des Plaines Ava. Dot Plaines, llhnob $0016 ' Tot. (312)296-6888 . t, .. CINCINNATI, OHIO 4523$ 6041 Hosbrook Pood Tot (613) 984-1100 ; DETROIT* MICHIGAN . 600 Northland Towers Woat Southftek!, Michigan 49075 lot (813) 357-0910 :; HOUSTON TEXAS 77027 1301 Pott Ook tower 5051 Wpsthoimor Root) Tot (H3) 621-9550 ' ^ 10$ ANGELES, CALIFORNIA $0022 6$70E F/ot/fla St lot (213) 723 2492 , NEW YORK, NEW YORK 10036 1114Avenue of tt>a Americas . v Tot (212) 764-5000 ' ST. LOUIS, MISSOURI S31B6 600 N lindberphBMI " *' Tot. (314) 694-1000 , ' SAN FRANCISCO BAY AREA's ^ 2710 Lafayette Santo Clara, California 95052 Tot. (408) 243-0414 ' SEATTLE, WASHINGTON 96121 - ' ' 2112 Third Avenue To! (206) 622-4203 s WILMINGTON, DELAWARE 19810 Suita 204. Bancroft Bktg. >> ' > : , 3411 SihrOrskto Rood Tot (302) 476-4600 >r > Monsanto Industrial Chemicals Co. A Unit of Monsanto Company 800 N. Lindbergh Blvd., St. Louis. Mo.*31M *a h | ,S^`W4*SS;h'*, M vw' v ^ ** * Monsanto 07f>171 7 Jt. 2~|43812?3^ tltho In V.i.A. TOWOLDMONOQ29104