Inspection before disintegration

During disassembly inspection, all parts should be carefully marked, and the marks should be accurate, firm and eye-catching, and records should be made to ensure the original disassembly.

5.2.2 Remove wires and accessories.

5.2.2. 1 Dismantle the high and low voltage side buses of the transformer, and properly place the dismantled buses to prevent deformation or loss.

5.2.2.2 releases transformer oil from oil storage tanks and coolers, and removes gas relays, thermometers, grounding wires and cables. Remove the cooler and oil storage tank.

bell jar

5.2.3. 1 bell jar shall be carried out in sunny days, with ambient temperature not lower than 0℃, humidity not higher than 85% and body temperature not lower than ambient air temperature. When the body temperature is lower than the ambient air temperature, the body should be heated, and the temperature should be higher than the ambient air temperature 10℃.

The surrounding area of the construction site should be cleaned and necessary dustproof measures should be taken.

5.2.3.2 put transformer oil above the coil, opened the handhole door of the high and low voltage leads, and removed the leads; Remove all accessories connected with the bell jar, such as high and low pressure side sleeves, lifting seats and pressure relief devices.

5.2.3.3 drained the oil from the transformer oil tank and removed the bolts around the big cover. When there is oil in the oil tank, it is forbidden to take off the big cover to prevent the box from being deformed.

When lifting the 5.2.3.4 bell jar, the included angle between the sling and the plumb line should not be greater than 30℃. If necessary, the hanging beam can be controlled. In the process of lifting, there should be a special person to monitor and the body should not collide with the box wall.

The bell jar hoisted by 5.2.3.5 should be placed stably on the clean and stable special sleepers.

When the relative humidity of air in 5.2.3.6 is less than 75%, the exposure time of human body to air shall not exceed 16 hours; The exposure time of the body to air is calculated from the beginning of oil discharge to vacuumizing or oiling.

Core maintenance

5.2.4. 1 Maintenance personnel entering the machine body should wear special work clothes, and shall not carry other articles except necessary tools; Tools used shall be fastened with white cloth belts; It is forbidden to scratch feet, step on coils, brackets and leads.

5.2.4.2, check whether the surface of the iron core is clean and free of grease and rust. For grease or rust, wipe it with a clean cloth and rinse it with qualified transformer oil.

5.2.4.3 should check that the surface of iron core should be smooth, without burr, local short circuit overheating and discharge trace. Insulation paint film shall not fall off. If there is any warping or irregularity in the laminations, it shall be leveled with a wooden hammer or a copper hammer, and there shall be no short circuit between the laminations. Burrs, mechanical damage or burns should be treated and coated with insulating paint.

5.2.4.4 checks the tightness and insulation of the upper and lower iron core clamps, square iron and winding pressure plate.

5.2.4.4.1Open the connector between the upper and lower clamps and the iron core, and the connector between the steel pressure plate and the upper clamp. Good insulation is maintained between the measuring core and the square iron, pressure plate and anchor bolt of the upper and lower fixtures, and there is no obvious change compared with previous tests.

5.2.4.4.2 There should be obvious and even clearance between the steel pressure plate and the iron core. Insulating pressure plate shall be intact, free from damage and cracks, free from creeping electric burns and discharge marks on the surface, and properly fastened.

5.2.4.4.3 Steel pressure plate shall not constitute a closed loop.

5.2.4.5, check the contact between the pressure nail and the insulating washer. Check the tightness of each fastener. Tighten the fastening bolts of upper and lower clamps, square nails and other parts one by one with a special wrench to fasten the bolts. The positive and negative pressure nails and locking nuts on the splint are not loose and have good contact with the insulating washer. Fasteners with insufficient mechanical strength or obvious deformation should be replaced.

5.2.4.6 used a special wrench to tighten the piercing bolts of the upper and lower iron cores, and inspected and measured the insulation of the piercing bolts to the iron core. Compared with previous tests, the insulation resistance has no obvious change.

5.2.4.7 checks that the oil circuit of each part of the iron core is unobstructed, and the cleaning pad is free from falling off and blockage, and arranged neatly. When clearing the blockage in the oil passage, care should be taken not to damage the insulation of the iron core or coil.

5.2.4.8, check the connection and insulation of the core grounding plate. The iron core is only allowed to be grounded at one point, and the grounding is good. After the grounding piece is removed, the insulation between the iron core and the ground should be good. If there is multi-point grounding, find out the reason and eliminate it.

The joint between the upper and lower yokes of 5.2.4.9 iron core and the clamp should be tightly pressed, and the connection is reliable. When the upper part of the coil is provided with an open pressure ring for pressing the coil, each open pressure ring is also connected with the clamp.

5.2.4. 10 The electric field shielding insulation of the iron core should be good and the grounding should be reliable.

Maintenance of coils and wires

5.2.5. 1 Check the surface of the coil, which should be clean and free of oil. There is no inclination and displacement of the whole winding, and there is no obvious pop-up phenomenon in the radial direction of the conductor.

5.2.5.2, check the insulation pads of all parts of the winding, which should be arranged neatly, with equal radial spacing and vertical radial direction. The bracket shall be fastened with proper compression force, and its compression screw and back cover shall be fastened. The position of the iron fist under the compression screw is correct. The exposed winding length of the gasket shall at least exceed the thickness of the winding wire.

5.2.5.3, check that the insulation of the coil is not damaged. The root of each wire shall be firmly bound and shall not be loose. Press the insulation surface with your fingers to identify the insulation quality and aging degree;

First-class insulation: the color is fresh, and the surface of insulation layer is soft, tough and elastic. No residue is left after hand pressing. This insulation is very good.

Secondary insulation: dark color, hard and solid insulation layer, traces after finger pressing, but no cracks. This insulation is qualified.

Three-level insulation: the color is black, the insulation layer is hard and brittle, and there are a few cracks and deformation after hand pressing. Can barely use it, but it is not reliable.

Four-level insulation: the insulation layer is fragile, and cracks and spots have appeared on the surface. After being pressed by hand, the insulating layer will fall off. This kind of insulation can no longer be used, it needs to be replaced and bandaged again.

5.2.5.4, check the coil oil circuit and keep it clear. There is no accumulation of grease and other sundries. For grease or debris blockage, you can gently wipe it with a soft brush or silk cloth, so as not to damage the insulation.

5.2.5.5, check the spare partition and casing.

5.2.5.5.1Clean, no damage, complete binding, and the outlet of tap lead is well closed. There are no signs of deformation, heating and dendritic discharge in the shell.

5.2.5.5.2 The starting point of the shell should be placed on the pad of the winding, and the joints must be staggered to prevent the oil circuit from being blocked.

5.2.5.5.3 Check that there is no leakage on the long pad supporting the shell.

5.2.5.5.4 The interphase partition shall be complete and fixed.

5.2.5.6 lead repair

5.2.5.6.1The lead wire is insulated and wrapped in good condition, without deformation, embrittlement, broken strands and card injury.

5.2.5.6.2 For the conductor passing through the cable, a layer of white cloth tape should be wrapped around the conductor to prevent the conductor from contacting with the casing conduit and causing shunt burn.

5.2.5.6.3 There shall be no overheating and welding at the lead joint and welding place. Exposed metal parts should be smooth, without burrs and sharp corners. The joint surface should be smooth, clean and free of dirt.

5.2.5.6.4 The lead length shall be appropriate without distortion.

Maintenance of 5.2.5.7 Insulation Support

5.2.5.7.1Insulation and supports shall be free from damage, cracks, bending, deformation and burns.

5.2.5.7.2 Insulating bracket and iron splint can be fixed with steel bolts, and insulating parts and insulating bracket can be fixed with insulating bolts. Both types of bolts need anti-loosening measures. At the same time, the inspection needs to be tightened one by one with a wrench, but be careful not to damage the bolt or insulator when applying force. Note that epoxy bolts cannot be used when replacing bolts.

5.2.5.7.3 Insulating clips shall be placed on the fixed lead. (Additional insulation) to prevent damage to the conductor insulation.

5.2.5.7.4 The spacing between insulation clips of fixed wires shall meet the standards. Prevent short circuit of wires under the action of electrodynamic force.

5.2.6 Maintenance of Tap Changer

Maintenance of non-excitation tap changer

5.2.6. 1. 1 Check that the tap-changer contacts are free from burns and overheating, and the tap-changer is clean, closely contacted and elastic; Check all exposed parts with a feeler gauge of 0.05× 10㎜, and the feeler gauge should be filled endlessly.

5.2.6. 1.2 The insulating cylinder shall be clean and free from oil stain, crack and flashover.

5.2.6. 1.3 The rotating contact shall stay at all positions correctly and be consistent with the position indicated by the indicator.

5.2.6. 1.4 The pull rod, tap cam, small shaft and pin of the switchgear shall be intact, and the turntable shall be flexible and well sealed.

5.2.6. 1.5 Before and after adjusting the tap-changer position, measure the DC resistance of the winding to meet the requirements of the regulations.

5.2.6.2 on-load voltage regulating device

5.2.6.2.1The on-load tap changer of German MR company is adopted for the startup transformer of our company, and the switch core is pulled out for inspection if necessary. For inspection contents and maintenance process, please refer to the relevant part in Article 7.2.6 of Electrical Primary Maintenance Regulations for 55MW Units.

5.2.6.2.2 Check that the selector switch and range switch of the on-load voltage regulating device should be in good contact, the tap lead should be firm, the switch part should be well sealed, and the current limiting resistor should be intact without fracture.

5.2.6.2.3 Check that the transmission mechanism, motor, transmission gear and transmission rod in the control mechanism are firmly fixed, flexible in operation and free from jamming; The friction part of the transmission mechanism is coated with proper grease.

Maintenance of fuel tank

5.2.7. 1 There is leakage repair welding such as sand holes in the welding spots and welds of the fuel tank. Eliminate the leakage points found in operation.

5.2.7.2, clean the inside of the fuel tank. Remove the oily impurities accumulated on the inner wall of the tank to ensure that the tank is clean and corrosion-free.

5.2.7.3 cleans the special circulating pipeline for heavy oil. Check whether the conduit is firmly connected and undamaged.

5.2.7.4, check whether the joint surface of bell jar and flange is clean and smooth. If groove marks are found, they should be ground flat.

5.2.7.5 checked the paint inside. Parts with complete internal paint and firm attachment, and some peeling and rusting parts should be treated and repainted.

Maintenance of air cooler

5.2.8. 1 Clean the surface of the cooler, and use high-pressure water to clean the dust blocked between the tube bundles. If the oil scale is serious, it can be cleaned with metal cleaning agent, thus improving the cooling conditions of the cooler.

If necessary, 5.2.8.2 should disassemble the cooler for maintenance. Check the cooling pipe and replace the sealing rubber washer. It is required that the cooling pipe is not blocked, and the interior of the oil chamber is clean and well sealed.

5.2.8.3 conducted a leak test on the cooler. Seal the flange of the joint with a cover plate and test the leakage by increasing the oil pressure. The standard is as follows: 0.05-0. 1mpa 10h for chip radiator.

If there is leakage in the pipeline, both ends of the leaking pipeline can be blocked with tapered brass rods (expanding pipes can be used to replace new pipelines if possible), but the number of blocked pipes should not exceed two per loop, otherwise the capacity will be reduced or replaced again.

In 5.2.8.4, gas welding or electric welding is used to repair the leakage points found in operation, so as to completely eliminate the leakage points. When welding, welding slag should be strictly prevented from falling into the radiator.

5.2.8.5 uses qualified transformer oil circulation to clean the interior to ensure the cleanliness of the cooler.

5.2.9 Maintenance of cooler fan

5.2.9. 1 Disassembly and maintenance of impeller

5.2.9. 1. 1 Open the stop washer, loosen the cap nut, exit the stop washer, and use special tools to remove the impeller from the shaft. After disassembly, properly keep the key and taper sleeve. When disassembling, the impeller should be prevented from being damaged and deformed.

5.2.9. 1.2 Check that the blades are riveted firmly with the wheel cover and there is no crack in the blades.

Put the impeller on the platform and check the installation of the blades. The angles of the three blades should be consistent, or they should be adjusted.

Disassembly and maintenance of 5.2.9.2 motor: For motor maintenance, please refer to the motor maintenance regulations.

5.2.9.3 zuzhuang

5.2.9.3.1Install the motor on the air cooler and fix the bolts in the air duct.

5.2.9.3.2 Replace gasket and baffle, install gasket, sealing rubber gasket, taper sleeve, Ping Jian and impeller at the extended end of motor shaft, install 5.2.9.3.3 stop washer, tighten cap nut and lock it with stop ring.

5.2.9.3.4 After assembly, pull the rotor by hand and rotate flexibly. There is no collision between the blades and the air duct, so install the protective cover.

5.2.9.3.5 Connect the working power supply, try to turn positive for minutes, and the operation should be smooth. When the sound and vibration are normal, disconnect the power supply.

Paint. The paint film is required to be uniform, without paint bumps and bubbles. Before painting, butter the nameplate and wipe it clean after completion.

5.2. 10 220KV oil-paper capacitor bushing 220KV maintenance

5.2. 10. 1 Clean and wipe the whole casing. Make sure that the surface of the shell is free of dust and grease.

5.2. 10.2 Check the casing oil storage tank. The oil level and oil color shall ensure that the oil level is in the middle and upper part of the oil gauge, that is, 1/2-2/3. If the oil level is low, the same brand of transformer oil should be replenished through the oil filler plug.

Check the joint surfaces for leaks. When reassembling, replace the oil-resistant gaskets on all joint surfaces. Tighten the wiring cap to prevent water and moisture.

5.2. 10.4 Check whether the porcelain skirt is cracked or damaged.

5.2. 10.5 All electrical tests on shell and oil shall comply with the requirements of test regulations.

Maintenance of pressure relief device

5.2. 1 1. 1 Remove the pressure relief valve from the transformer oil tank and seal the removed hole with a cover.

5.2. 1 1.2 Clean the dirt in the protective cover and guide cover and keep it clean.

5.2. 1 1.3 Check that the connecting bolts and pressure springs of all parts are in good condition, free from corrosion, and have good spring elasticity.

5.2. 1 1.4 Conduct an action test to confirm that the pressure values for opening and closing the valve meet the standards.

5.2. 1 1.5 Check that the microswitch should be flexible, with good contact and correct signal.

5.2. 1 1.6 Replace the sealing rubber gasket to prevent oil leakage.

5.2. 1 1.7 When installing, pay attention to the uniform fastening of the connecting bolts between the pressure reducing valve and the transformer box. After oil filling, the exhaust valve on the pressure relief valve pipeline should be opened, and the valve can only be closed when oil flows out of the exhaust valve.

Maintenance of valves, butterfly valves and plugs

5.2. 12. 1 Check whether the rotating shaft, baffle and other parts of the valve are complete, flexible and tight. If necessary, replace the gasket and parts. After the 0.05MPA oil pressure test, the baffle was closed tightly without leakage. The shaft is well sealed, and the sign indicating the opening and closing position is clear and correct.

5.2. 12.2 Remove the valve for maintenance, grind the contact surface and replace the sealing packing. Defective parts should be complete, and valves with serious defects should be replaced.

5.2. 12.3 The repaired valve shall be subjected to a pressure test of 0. 15MPA to avoid oil leakage.

5.2. 12.4 Thoroughly inspect the oil drain plug, vent plug and sampling door of the transformer body and accessories, replace the sealing rubber gasket, and check that the threads are in good condition and there is no leakage on all sealing surfaces.

Maintenance of moisture absorber

5.2. 13. 1 Dismantle the moisture absorber, pour out the internal adsorbent, check whether the glass cover is in good condition and clean it.

5.2. 13.2 put the dried adsorbent (color-changing silica gel) into the moisture absorber, with the loading capacity of about 4/5 of the volume of the glass cover, and the adsorbent particles are not less than 3 mm ..

5.2. 13.3 If there is no new adsorbent, the original adsorbent can be put into a drying oven, heated to 120OC- 160OC, kept for 5H, and can be reused after being reduced to blue.

5.2. 13.4 All sealing rubber gaskets shall be replaced during reassembly.

5.2. 13.5 Pour the old oil in the oil outlet cover, clean the oil cover, inject new qualified transformer oil and tighten the cover. Pay attention to the normal oil level or slightly higher when refueling.

5.2. 13.6 If a new dehumidifier is replaced, the gasket should be removed first.

Maintenance of diaphragm oil storage tank

5.2. 14. 1 Remove the headers of all parts (moisture absorber, oil filler, exhaust pipe, gas relay header, etc.). ) and clean them, and seal the nozzle to prevent foreign objects from entering.

5.2. 14.2 Remove the connecting rod of the pointer oil level gauge through the top window, remove it together with the oil level gauge, and keep it properly.

5.2. 14.3 Remove the connecting flange bolt in the middle of the oil storage tank, take out the partition, clean it, keep it clean and dry, and check that there is no damage or breakage.

5.2. 14.4 Clean the upper and lower oil tanks and drain the oil in the dust collector. Wipe the box wall with a clean and hairless cloth to keep the inner wall clean and the paint film complete and uniform. If the paint film falls off, please touch it up. (The inner wall is painted with insulating paint, and the outer wall is painted with the same paint as the car body. )

Replace the seal at each connecting flange.

Maintenance of gas relay

5.2. 15. 1 Remove the gas relay, remove the oil stain on the surface, and check that the glass window of the container, vent valve, oil drain plug, junction box and small sleeve are intact, and the arrow marks on the cover plate and terminal are clear.

5.2. 15.2 After the relay is filled with transformer oil, there should be no leakage when it is pressurized for 0. 15MPA/30MIN at room temperature. After passing the test, rinse with qualified transformer oil.

5.2. 15.3 The gas relay shall be calibrated by professionals.

5.2.65438+ The gas relay shall be kept in a horizontal position after installation, and the connecting pipe shall have an ascending slope of 1%- 1.5% towards the oil storage tank.

The inner diameter of the sealing rubber gasket of the connecting pipe flange is larger than the inner diameter of the connecting pipe, and the valve between the gas relay and the oil storage tank should be installed near the oil storage tank. The diameter of the valve should be the same as the pipe diameter, and it should be clearly marked with "open" and "closed".

5.2. 15.5 The installation of the gas relay should make the arrow face the oil storage tank, and the exhaust plug of the relay should be 50MM lower than the minimum oil level of the oil storage tank, so as to facilitate the core-pulling inspection of the gas relay.

5.2. 15.6 Install the gas gathering box and connect the gas gathering pipeline.

Inspection of temperature measuring device

5.2. 16. 1 Verify that the temperature of the temperature measuring device meets the accuracy requirements, check whether the contact action is correct, and adjust the action value as required.

5.2. 16.2 transformer oil should be injected into the top thermometer bracket, and the seal should be good without leakage.

Reinstallation of transformer

5.2. 17. 1 All parts shall be assembled according to the marks made during disassembly and the reverse order during disassembly.

5.2. 17.2 Clean the sealing surface, which should be smooth and clean; Replace the sealed oil-resistant rubber gasket. The gasket should be wiped clean and the installation position should be accurate. Its lap thickness should be the same as that of the original rubber gasket. Tighten the bolts evenly, so that the compression of the rubber washer does not exceed 1/3 of the original thickness.

5.2. 18 vacuumizing and vacuum oiling

5.2. 18. 1 220KV transformer must be filled with vacuum oil; Transformer oil must be inspected according to regulations before it can be injected into the transformer. Before different brands of oil or new oil of the same brand are mixed with waste oil, an oil mixing test must be carried out.

5.2. 18.2 If the body inspection and overall reassembly are completed on the same day, vacuum oil injection shall be carried out immediately. If the whole reassembly cannot be completed on the same day, qualified transformer oil should be injected in time, and vacuum oil injection should be carried out after the next day.

5.2. 18.3 Before vacuumizing, close the auxiliary valves that cannot be vacuumized, such as oil storage tanks; The on-load voltage regulating transformer should discharge the oil in the switch chamber at the same time as the main body, and connect the oil chamber of the on-load switch with the transformer oil tank with a union pipe, so that the switch and the transformer can be vacuumized at the same time, and the oil circuit should be connected to facilitate the main body to inject oil at the same time.

5.2. 18.4 install a vacuum line and a meter at the flange of the gas relay header, and connect it to the vacuum equipment (if the vacuum is pumped through the oil storage tank, it should be installed and implemented according to the relevant requirements of the oil storage tank). Install an oil pipe at the oil drain valve of the next oil tank and connect it to the oil tank through the oil filter.

5.2. 18.5 Start the vacuum pump, uniformly increase the vacuum degree, and vacuumize to 0.098 MPa；; ; When vacuumizing, monitor and record the deformation of the oil tank. The vacuum holding time of 220KV voltage level is not less than 6H, and then qualified transformer oil heated to 50-60℃ is injected under vacuum, and the oil injection speed is less than 4t/h; When the on-load transformer is oiled to 100-200mm box cover, stop oiling, keep vacuum for more than 6h, and oil the on-load switch.

5.2. 18.6 When refueling, according to the rising height of the oil level, gradually open the oil guide pipe of the lifting seat, drain the oil with the exhaust plug at the top of the cooler, tighten the exhaust plug after draining the oil, refuel to the height of the gas relay, remove the manifold, install the gas relay, and refuel the oil storage tank through the butterfly valve at the top of the oil tank.

5.2. 18.7 After vacuum oil injection, hot oil circulation should be carried out to make the oil quality meet the requirements. When the hot oil is circulated, the oil temperature should reach 60-70℃, and the total oil quantity of the circulating transformer is generally 3-4 times.

5.2. 18.8 After oil injection, the transformer shall stand at 220KV for at least 72h.

Maintenance of foundation and other components

5.2. 19. 1 Check that the foundation guide rail is fixed firmly without deformation and the brake trolley device is firm.

5.2. 19.2 ontology and neutral point grounding is good.

5.2. 19.3 The accident oil drainage facilities are in good condition, and the fire fighting facilities are complete and can be put into use.

5.2.20 Carry out anti-corrosion and painting work on the transformer as required.

5.2.2 1 Conduct related electrical tests according to the electrical preventive test regulations of Jiangsu Province.