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Instructions for InerteenInsulating Fluid P.D.S. 54201 CM and Installation and Maintenance of Inerteen Transformers t * Westinghouse Electric Corporation Power Transformer Division, Sharon, Pa. I. B. 45-063-99B Effective September, 1968 Supersedes I.B. 45-063-99A April 1968.1.L. 48-650-2 August 1951. LL. 48-650-3 May 1951,1.L. 48-6504 May 1951.1.L. 48-650-5B September 1962, I.L. 48-650-6 May 1951.1.L. 48-6507 June 1951 and l.L. 47-069-6 January 1965. t NPC00026547 753884 2 Contents Page PART ONE - INERTEEN INSULATING F L U ID ................................................................. 3 Characteristics................................................................................................................................ H andling......................................................................................................................................... Storing ........................................................................................................................................... Testing Service ............................................................................................................................. R e c o n d itio n in g ............................................................................................................................. Causes of Deterioration...................................................................................................... 3 3 4 4 5 5 PART TWO - MAINTENANCE AND INSTALLATION OF INERTEEN TRANSFORMERS................................................................. 6 I n s ta l la ti o n ........................................................................................................................ 6 Inspection.......................................................................................................................... 6 Accessories and Fittings..................................................................................................... 7 F in ish ................................................................................................................................ 7 Filling.......................................................... ."j................................................................... 7 Filling Under Vacuum..........................i................................................................... 7 Placing in Service........................................... j1.................................................................. 8 Pressure Testing...................................a.................................................................... 8 High Altitude ........................................................................................................... 8 Grounding Transformer Tank ...........J ..................................................................... . 8 Grounding Low Voltage Winding.............................................................................. 8 Making Connections......................................................................................................... 9 Voltage Application................................................................................................... 9 Inspection....................................................................................................................... 9 Sampling Inerteen....................................................................................................... , . . 9 Quantity of Sample.............................................................................................J . . 10 N P C 0 0 0 2 6 5.4*_8 753885 Part I - Inerteen Insulating Fluid 3 CHARACTERISTICS 5. Dielectric constant: Inerteen is a highly pure, synthetic non-inflammablc and non-explosive insulating and cooling liquid. Chemically stable and nearly water white in color. Inerteen is not affected by reaction with other materials regularly used in the manufacture of Inerteen apparatus. It is non-oxidizing and non-corrosive at temperatures considerably above those normally obtained in Inerteen apparatus. Inerteen will not sludge under any operating condition. Water is the main enemy of Inerteen and keeping it dry' will insure long service life. The dielectric strength of Inerteen will com pare favorably with that of insulating oil when tested under the same conditions. Quality samples of Inerteen tested under laboratory conditions may show a dielectric strength in excess of 40 kv. Care must be exercised in handling and testing Inerteen. Inerteen must be kept in clean, sealed containers to prevent loss by evaporation or contamination by moisture or dirt. Inerteen exerts a strong solvent action on ihost varnishes, gums, and paints. Such materials are not used in the construction of Inerteen appa ratus. No materials should be used in Inerteen apparatus except those approved by the Westinghouse Electric Corporation. Inerteen has an irritating effect upon the skin. If it is necessary' to handle it. see the caution note on the title page. It should be remembered that mineral oil is completely miscible with Inerteen: in fact, it is impossible to separate mineral oil and Inerteen. Specific Characteristics of Inerteen As outlined in "Method of Testing Askarels A.S.T.M. D901." the specific characteristics of Inerteen arc: 1. Burn point: None At 1000 cycles 77F (25C). 5.7 to 5.9 At 1000 cycles 21 2F ( 100C), 4.8 to 5.0 6. Dielectric strength: (Minimum) 77F (25C> At point of shipment. 35 kv At point of receipt. 30 kv 7. Electrical Resistivity: (Minimum) 500 x l O9 ohms/cm3 (212F (I00C) at 500 volts d-c) 8. Power factor: At 60 hertz. 77F(25C) 27c At 60 hertz. 2)2F(100C ) 257 9. Fixed chlorine content: (Minimum) 42 per cent 10. Free chlorides: Less than 0 .10 ppm 11. Neutralization number: Less than 0.014 mg of NaOH/gram 12. Pour Point: (Maximum) plus 2F (minus I9C) 13. Refractive index: * At 77F (25C), 1.624 to 1.626 14. Specific gravity: At 60F/60F (l5.5C /r5.5C ). 1.381 to 1.392 15. Density: 11.5 pounds per gallon 16. Viscosity: At 100F (37.8C), 82-92 seconds 17. Moisture: (Maximum) 35 ppm 2. Chemical stability: No generation of free HANDLING chlorides under normal operating conditions 3. Color: (Maximum) 100 A.P.H. 4. Condition: Clear CAUTION Inerteen is a skin irritant. Unnecessary con tact with the liquid or its vapor, particularly N P C 00026549 7COOOP 4 when hot, should be avoided. The eyes, nose, and lips are effected when Inerteen comes in contact with them. All safety precautions must be observed when handling inerteen._________________________ _ If accidently spilled on the hands, no skin irritation will occur if the parts are thoroughly washed with soap and water. Continued exposure may cause eruptions on some individuals due to the absorption of Inerteen through the pores of the skin. Hot apparatus should not be opened except in a well-ventilated area. Large quantities of Inerteen should be handled in a closed system. In case Inerteen is spilled on one's clothing, the clothing should be changed at once and laundered * before being worn again. Inerteen resistant gloves should be worn when it is necessary to work in Inerteen. If Inerteen gets into the eyes, flush with water and get eye first aid from a physician. Castor oil is recommended for the eyes, castor oil or skin cream for the nose and lips. CLEANLI NESS AMONG WORKMEN HANDLING INER TEEN IS A VERY GOOD SAFEGUARD AGAINST SKIN IRRITATION. NOTE Always use all-metal hose or pipe when handling the Inerteen. Rubber hoses should not be used. Inerteen can easily become contaminated from the rubber, and should not be allowed to come in contact with it. When it is necessary to transfer Inerteen to apparatus the apparatus must be at least as warm as the Inerteen. All Inerteen should be circulated through an Inerteen conditioner or filter press to remove scale or rust. A drum of cold Inerteen when taken into a warm room will "sweat'*, and the resulting moisture on the surface may mix with the Inerteen as it flows from the drum. Before breaking the seal, the drum should therefore be allowed to stand long enough to reach room temperature, which may require eight hours, or even longer under extreme temperature condi tions. STORING Drums As soon as a drum of Inerteen has been unloaded, the bung should be examined and tightened if it is loose. It is possible for bungs to become loosened by change in temperature or rough handling in transit. Be sure all Inerteen is tested before using. It is desirable that Inerteen in drums be stored indoors. Outdoor storage of Inerteen is always hazardous to the Inerteen and should be avoided if at all possible. If it is necessary to store Inerteen outside, the drums should be placed so that the bungs are down so they are protected from moisture. It is desirable to cover the drums with a tarpaulin. TESTING SERVICE Many users of Inerteen do not have the necessary facilities for testing it. In order that these users may be able to make the periodic tests recom mended, Westinghouse Electric Corporation has established an Inerteen testing service to provide a pareful test by experienced engineers, and a prompt report of test results, i ; Two special 16 oz. sample bottles per mailing tontainer (W) S#1608629, as well as necessary Backing and printed matter, may be obtained by ontacting the nearest W'estinghouse Office. (The bottle and the container will not be returned to the customer.) After drawing the sample of Inerteen, the customer should seal the bottle and rgail it to the Westinghouse Electric Corporation. Plant Labora tory, Sharon. Pcnna. To simplify these details, an Instruction and order sheet and a printed return label have been included in the carton container. The instructions cover the taking of the sample and its proper preparation for mailing. The order sheet must be sent to the nearest Westinghouse Office. When samples of Inerteen are received for testing, they are sent to the Plant Laboratory and tested in accordance with standard A.S.T.M. methods. In addition to dielectric tests, Westinghouse is also prepared to make a physical and chemical examination if so requested. (The customer should plainly indicate the type of service de sired.) The physical and chemical examination con sists of an examination of the Inerteen by a competent chemist. Recommendation^ w((l be ( ,, . ..._*-t=r^HiPC00026550 F - .. ... 753887 5 made as to the suitability of the Inerteen for continued use, whether it would be desirable and economical to clean it, and in a general way, the preferred method of cleaning In submitting samples for this service, the history of the Jnerteen represented should be given as com pletely as possible. Power factor test of Inerteen at 60 cycles can be made. The blotter filter press and the Inerteen condi tioner will remove water and dirt deposits which may be present. Of the two methods, the Inerteen conditioner is the most effective in removing these two contaminating agents. Any equipment used for filtering Inerteen should first be thor oughly cleaned with benzine or naphtha. Every trace of any material foreign to Inerteen must be removed. If at all possible separate equipment should be used for filtering Inerteen only. (For details refer to the nearest Westinghouse Office.) RECONDITIONING Causes of Deterioration The principle causes of deterioration of Inerteen are: 1. Presence of water. 2. Arcing. % j 1 Arcing or burning in Inerteen produces finely divided carbon and gases which are mostly hytlro- gen chloride. Hydrogen chloride in the presence of moisture forms hydrochloric acid which may soon damage the insulation in the apparatus and cause rusting of ferrous materials. Since hydrogen chloride is formed quickly after the arcing occurs, neither the Inerteen nor the apparatus should be exposed to the atmos phere (which always contains more or less mois ture) until an attempt has been made to remove the hydrogen chloride. Reconditioning Reconditioning will be necessary to remove water, dirt and hydrogen chloride which may be present and contaminating the Inerteen. Hydrogen chloride, caused by arcing, may be eliminated by vigorously bubbling dry nitrogen through Inerteen. The nitrogen should be passed through the drain valve at the bottom of the apparatus and allowed to escape through a vent at the top. The nitrogen should be discharged through a pressure regulator attached to a stand pipe above the level of the Inerteen in the apparatus to prevent the Inerteen from flowing into the regulator. The nitrogen should be bubbled through the Inerteen at a rate of one to three cubic feet per minute for a period of four to six hours. This will require from two to eight cylinders (220 cu. ft. each) of dry nitrogen, based on apparatus containing 150 to 2000 gallons of Inerteen. Immediate application of the bubbling process will reduce the destructive action of the hydro chloric acid on the working parts and insulation, thereby making it likely that the materials not damaged by arcing may be used in repairing the apparatus. Also, use of the process will in most cases make it possible to satisfactorily reclaim the arced Inerteen. After the hydrogen chloride has been removed by the bubbling process, the Inerteen should be reclaimed by use of an Inerteen conditioner. There is no commercially suitable method for separating transformer oil from Inerteen. r rnm m i- r .JJ^ gO T C O 0 0 26 5 51 753888 6 Par II - Installation and Maintenance of Inerteen Transformers INSTALLATION For convenience in handling, all transformers are equipped with lugs or eyes for lifting and moving the complete assembly filled with Inerteen by use o f a crane. Additional means are provided for the heavier parts such as covers, core and coils, radiators and terminal chambers. Jacking lugs are also supplied on either the base or corners of the tank. A transformer should only be lifted or moved by jacks placed against these lugs and not against the cooling tubes, radiator valves, or other fittings. An indoor installation requires that the room in which the transformers are placed must be well ventilated so that the heated air can readily escape and be replaced by cooler air from the outside. If the room is poorly ventilated, this exchange o f air takes place too slowly and the temperature of the air in the room may become excessively high. At any given load the temper ature rise o f a self-cooled transformer will be a fixed number o f degrees above the'temperature o f the surrounding air. The temperature o f the transformer is the sum o f this rise and the air temperature; therefore, care must be taken to provide a room sufficiently ventilated to permit operation o f transformers at a reasonable temper ature. Area o f the air inlets should be such that the ambient temperature never exceeds 40C (I04F> with an average over twenty-four hours not exceeding 30C (86F): 50 to 60 square feet per 1000 kva o f transformer capacity has been satisfactory. Outlet openings with the same total area should be provided. Self-cooled transformers should always be well separated from one another and from adjacent walls, partitions, etc., in order to permit free air circulation about the bases. This separation should not be less than 24 to 36 inches depending on the size o f the units. INSPECTION When a transformer is shipped complete and filled with Inerteen, this inspection should in clude a check o f the Inerteen level, the tightening or adjustment o f any parts that may have become loose or out o f place, and determining the extent to which moisture may have entered the trans former. The latter can best be determined from the dielectric strength o f the Inerteen. Inerteen used for filling transformers should have a dielec tric strength o f 30 kv or higher. When it tests less than this the Inerteen should be filtered. If the dielectric strength is very low or if there is any other evidence o f moisture, it is necessary to dry the transformer. Inerteen transformers should be dried by the short circuit method with the transformer im mersed in the Inerteen and with the tank sealed ightly. During the drying out operation, the nerteen should be circulated through a filter press or preferably through an Inerteen condi tioner. A fitter press will remove dirt and most o f the moisture, but the conditioner will remove these and other contaminating materials as well. The desired load current should be obtained by short circuiting one winding and impressing the proper impedance voltage on the other winding. The full load impedance may usually he found on the instruction plate for the transformers; if the impedance o f the transformer is not known, it should be requested from the Westinghouse Elec tric Corporation, Sharon. Pennsylvania, by identi fying the transformer with its serial number. If the transformer is at or lower than room temperature at the start o f the drying process, circulation o f 125 t 1507c o f full load current will hasten the heating, and a higher top Inerteen temperature can be obtained more quickly by blanketing the coolers when tubular coolers are used or by shutting o ff the radiator valves when radiators are used. The cover should be lagged to prevent condensation. All Inerteen transformers are carefully inspected and tested at the factory and they are in good condition when shipped; but it is desirable to inspect each transformer thoroughly before plac ing it in service. The loading should be carefully watched and when the top Inerteen reaches a temperature o f 60C, the load should be reduced to obtain an approximately constant top Inerteen temperature based on the following table: NPC00026552T 7 Short Circuit Amperes in Percent of Load SO?? 75% H5% Maximum Temperature o f the Top lnerteen 85C 80C 75C To do this, clean the damaged portion by means of a scraper or sandpaper, wipe thoroughly with a solvent dampened cloth, apply Westinghouse primer paint and allow it to dry for at least 24 hours, then apply a coat o f Westinghouse finish paint. While the windings o f the transformer heat up, do not permit the temperature o f the top lnerteen to exceed the value specified for a given percentage o f load. This precaution is necessary because the windings will heat up more quickly and operate at a higher temperature than the lnerteen. If the windings are allowed to reach too high a temperature, the insulation will be dam aged. The drying o f a transformer should be continued until the dielectric strength o f samples o f lnerteen taken from the transformer test at 30 kv or higher. The cover should be kept tightly sealed during the temperature run, and until the transfohner has cooled down to room temperature to prevent condensation, This also prevents the release o f hot lnerteen vapors which are quite objection able. particularly if the ventilation is poor. 4 CAUTION It is not safe to attempt the drying out of transformers unless constant attention is given to the job. ACCESSORIES AND FITTINGS Bushings, fittings, and accessories when boxed and shipped separately should be mounted as shown on the outline drawing. Proper installation instructions when necessary are included in the instruction leaflets for component parts. Care must be exercised when these components are fitted to eliminate the accidental introduction o f moisture in any form inside the transformer. Where blind flanges are removed before fittings are mounted, the level of the lnerteen must be lowered below the openings that will be made. FINISH Any portion o f the paint film damaged during shipment or installation must be repaired as quickly as possible. FILLING Use only all-metal hose or pipe when filling, since the lining o f most other types o f hose may be soluble in lnerteen and will contaminate it in a short time. All joints should be tight; where practical, fill through the drain valve to keep aeration to a minimum and vent the top of the tank to allow the air to escape. Be sure that valves and pipe connections between the main tank and any lnerteen filled compartments are open for free circulation o f gas and liquid. Otherwise, trapped air or gas may cause the lnerteen level in some parts o f the transformer to be below the safe operating level. If it is necessary to fill a transformer out-ofdoors, particularly on a damp day, care should be taken to prevent the entrance o f moisture. In order to avoid condensation the temperature inside the unit should be kept several degrees above the outside air temperature. The tank and compartments, if any, should be filled at ambient temperatura to the point on the gauges marked "25-Liquid Level.1' If the ambi ent varies greatly from 25C (7 7 F ) when filled, the lnerteen level should be checked when the average fluid temperature is 25C; sufficient lnerteen should be added to or drained from the tank to bring the level to the proper height. The transformer should never be operated or left standing even out o f service without the lnerteen level being indicated on the gauge. Filling Under Vacuum Entrapped air is a potential source o f trouble in all liquid filled transformers. Therefore, it is desirable to fill all lnerteen transformers under a full vacuum. This is done for the transformers shipped from the factory and should be done where practicable when transformers are filled in the field, providing the transformer cases have been $0 designed. If the cases have not been designed for full vacuum and it is imperative to t 00265 i -! ff: - - - - i 753AQn get the maximum winding impulse strength imme diately, the transformers should be filled with Inerteen under full vacuum by placing them in an auxiliary vacuum tank. Where purchaser does not have an established technique for vacuum filling, the following pro cedures may be used whether vacuum is applied directly to the transformer or the complete transformer is placed in an auxiliary vacuum tank. 1. Apply and maintain continuously a vacuum of at least 28 inches of mercury for at least one-half hour to units rated 25 kv and below, or for four hours to units above 25 kv. * 2. While retaining the vacuum, slowly fill with Inerteen to the normal 25C level or with approximately 90% of the required amount where it is impossible to gauge properly. 3. Maintain the specified vacuum for at least one-half hour after filling. 4. Adjust Inerteen to normal level and seal the transformer tank. Do not reopen until the tem perature at the top of the fluid is equal to or higher than the ambient temperature in order to avoid condensation on the surface of the Iner teen. In those cases where the transformers are not filled under vacuum, full voltage should not be applied to the windings for several hours after the Inerteen has been put into the case. This time is necessary to allow the air bubbles to escape. PLACING IN SERVICE Pressure Testing All Inerteen transformers are pressure-tested at the factory and shipped free of leaks. After installations and before voltage is applied, it is desirable to pressure-test each transformer, espe cially if any fittings or covers have been removed and replaced during installation. Compressed dry nitrogen or dry air may be used for the purpose. It is recommended that the space above the Inerteen be blown out with dry nitrogen, then close all vents and apply a pressure-test of five pounds per square inch for a period of six to eight hours. The test pressure can best be limited by the use of a pressure regulator attached to the nitrogen cylinder. A check for leaks of joints above the Inerteen level may be made by painting them with a solution of soap and glycerin and watching for gas bubbles. At the conclusion of the test the internal pressure should be returned to normal by momentarily venting the gas space. High Altitude Where transformers are to be used at a high altitude (more than 3000 feet above sea level) a fitting above the liquid level should be opened to equalize the internal and external pressures at a temperature of approximately 25C before plac ing the transformer in service. Grounding Transformer Tank Regardless of the type of foundation or floor on which a transformer is to rest, the tank should be definitely and permanently grounded to eliminate the possibility of obtaining static shocks or being injured by accidental grounding of a winding to t$e case. A ground pad or lug is always provided near the bottom of the tank for the purpose of connecting the grounded lead. CAUTION A good low-resistance ground is necessary for adequate protection-a poor ground may be worse than none at all. * Grounding Low Voltage Winding Every effort is made in insulating transformers to guard against any chance of breakdown between high voltage and low voltage windings; however, in order to be absolutely safe, it is advisable that low voltage circuits with which persons may come in contact be grounded. The maximum voltage that can be obtained to ground is then limited to the normal voltage that exists between the grounded point and the line: this is true even though the high voltage and low voltage windings become connected electrically. In grounding the winding, the neutral point should be used if it is available. When trans formers operate on single phase circuits with the middle point of the low voltage, the maximum voltage that can exist between any part of the lowvoltage circuit and ground is one-half of the low voltages. I NPC00026554^ 9 MAKING CONNECTIONS A diagram, usually on the metal instruction plate attached to the side of the case, shows the proper power terminal connections to be made for various voltages. Care should be taken to see that all connections and only those shown are prop erly made, for a wrong connection may cause severe damage. Any increase in operating temperature at nor mal load should be investigated and if the cause cannot be determined, the transformer should be taken out of service and given a thorough inspection. Any symptoms, such as unusual noises, high or low Inerteen levels, operation of relief device, etc., should be investigated at once. Some installations require an auxiliary source of power or control leads to be wired to terminals at the transformer; a wiring diagram, either a separate drawing or included as part of the outline drawing, shows the connections to be made. Voltage Application When voltage is first applied to the transformer, it should, if possible, be brought up slowly tp its full value so that any wrong connection or $ther trouble may be disclosed before damage! can result. After full voltage has been applied success fully. the transformer should be operated without load for a few hours. It should be kept under close observation during this time and also during the first few hours while loaded. Transformers which have been subjected to unusually severe operating conditions, isuch as overloads, frequent short circuits, or special units should be inspected at least once a year. This can usually be done adequately by lowering the Inerteen level and inspecting with a light through the manhole. Before this inspection is made, the Inerteen should be allowed to cool to reduce the amount of Inerteen fumes given off which are quite objectionable and should not be inhaled. During periodic inspection, all accessories should be inspected to see if they are operating properly. SAMPLING INERTEEN INSPECTION It is desirable that periodic inspections of Inerteen apparatus be made and that samples of Inerteen be taken from each and from all compartments of any apparatus and tested after a short period of service (approximately three months for transformers). Following this, when operating conditions permit, routine sampling and testing of the Inerteen at intervals of six months to one year are suggested. Accurate records should be kept of such inspections and tests and if the Inerteen shows a dielectric strength of less than 28 kv, it should be conditioned. If facilities are not available for testing Inerteen. see "Westinghouse Inerteen Testing Service," P.L. 4S-825. When an appreciable amount of Inerteen is removed from any apparatus, it should be replaced with an equal amount of neve Inerteen so that the liquid level in the apparatus is maintained. The Inerteen used for replacement purposes should have a dielectric strength of not less than 30 kv. All sampling and testing equipment must be thoroughly dry and clean. It is recommended that sampling and testing equipment used for handling Inerteen and servicing Inerteen be used for no other purpose. Care must be used in taking samples of Inerteen and sealing them prior to testing. It is desirable that samples of Inerteen be removed from any container on clear days only, and when the temperature of the Inerteen is at least as high as the temperature of the surround ing air. Use only tin containers with screwed metal caps or glass bottles with Inerteen-resistant stop pers to hold Inerteen samples. If it becomes necessary- to use other than factory sampling containers, they should be rinsed with clean naphtha, washed with strong soap* suds, and rinsed thoroughly in hot water, and then dried at approximately J10C for four hours with neck down in a circulating air oven. If the containers are not used immediately after cleaning, they should be sealed tightly and stored in a dry, clean place. NPC000265 753892 pr ovision is made on all Inerteen transformers to obtain a top sample of the Inerteen, however, on a transformer that is in operation, a sample may be taken from either the top or bottom since any moisture present will be mixed in. due to circulation of the Inerteen. In sampling, allow a small amount of Inerteen to run out to flush the sampling connection clean before collecting the sample. The Inerteen should be put into the sample containers immediately and the caps screwed on tightly. The label for each container should be marked clearly with the serial number of the transformer or compartment from which the Inerteen was taken. Before taking samples from a storage tank, the ' Inerteen should be allowed to settle for approxi mately twelve hours so that if there is any moisture present, it. having a lower specific gravity, will rise to the top where the sample is to be taken. A clean sneak-thief should be used to obtain the samples. Essentially, the same pre cautions to prevent moisture and dirt contamina tion should be used as outlined above. Quantity of Sample It is recommended that one 16 oz. bottle of Inerteen be taken as a sample for testing. At least one sample should be taken from a tank car of Inerteen. One sample may be taken from each drum, or if desired, a composite sample may be made from Inerteen from five drums, provided all the drums are airtight. When the bung is first loosened, a hissing sound should be heard, which indicates that the drum has been airtight. If the test of the composite sample is not satisfactory, a sample from each of the drums represented should be tested. When drums have been stored exposed to the vyeather. a sample from each drum must be tested t<j determine if it i* suitable for use. i 4 Westinghouse Electric Corporation Power Transformer Division, Sharon, P i. Print! in U.S.A. (W.P.D.I 7COnftn