1. 1 This guideline is applicable to domestic oil-immersed power transformers, 6kV and above auxiliary transformers and similar equipment, such as arc suppression coils, voltage regulating transformers, static compensation device transformers and parallel (series) reactors.

Oil-immersed power transformers and similar equipment imported from China can refer to this guideline and be implemented according to the manufacturer's regulations.

1.2 This guideline is applicable to major, minor and temporary maintenance of transformer standard projects. Maintenance of non-standard items, such as replacement of windings and cores, is not included.

1.3 transformers and similar equipment should implement the policy of giving priority to prevention and combining planned maintenance with diagnostic maintenance, so that repairs should be made, repairs should be made if they are good, and practical results should be paid attention to.

1.4 The maintenance of on-load tap-changer shall be carried out in accordance with DL/T574-95 Guide to Operation and Maintenance of on-load tap-changer.

1.5 each network and provincial bureau may make supplementary provisions according to the requirements of these guidelines and the specific conditions of this region.

2 reference standard

Gb1094.1~1094.5-85 power transformer

Technical parameters and requirements of GB 6451.1~ 6451.5-86 oil-immersed power transformer

GB725 1-87 Guide for Analysis and Judgment of Dissolved Gases in Transformer Oil

GBJ 148-90 Code for Construction and Acceptance of Power Transformers, Oil-immersed Reactors and Transformers in Electrical Equipment Installation Project

GB7665-87 transformer oil

DL/T572-95 Operating Rules of Power Transformer

DL/T574-95 Guide for Operation and Maintenance of On-Load Tap Changers

3 Maintenance cycle and maintenance items

3. 1 maintenance cycle

3. 1. 1 overhaul cycle

3. 1. 1. 1 is generally overhauled once every 10 years after it is put into operation.

3. 1. 1.2 Unless otherwise specified by the manufacturer, overhaul can only be carried out when it is determined that there is internal failure or serious oil leakage in the engine body after tests and inspections in combination with the operation conditions.

3. 1. 1.3 After the main transformer running in the power system has an outlet short circuit, it can be considered to be overhauled in advance after comprehensive diagnosis and analysis.

3. 1. 1.4 When the transformer in operation is found to be abnormal or the internal fault is determined by test, it should be overhauled in advance; After comprehensive diagnosis and analysis of the normal transformer, the overhaul period can be appropriately extended with the approval of the chief engineer. People's Republic of China (PRC) issued 1995-06-29, Ministry of Electric Power Industry issued1995-1implementation.

3. 1.2 Minor repair cycle

3. 1.2. 1 general year 1 times;

3. 1.2.2 The minor repair period of transformers installed in polluted areas of Grade 2~3 shall be specified in the site regulations.

3. 1.3 Maintenance cycle of accessories

3. 1.3. 1 The calibration of protection device and temperature measuring device shall be carried out in accordance with relevant regulations.

3. 1.3.2 Disassembly and maintenance of transformer oil pump (hereinafter referred to as oil pump): two-stage pump 1~2 years, and four-stage pump 2~3 years.

3. 1.3.3 transformer fan (hereinafter referred to as fan) shall be disassembled and overhauled every 1~2 years.

3. 1.3.4 The replacement of adsorbent in the oil filter shall be determined according to the oil quality test results; The adsorbent in the dehumidifier should be replaced at any time according to the degree of loss.

3. 1.3.5 Automatic devices and control circuits shall be inspected once a year.

3. 1.3.6 The maintenance of water cooler shall be carried out once every 1~2 years.

3. 1.3.7 overhaul of the casing shall be carried out together with the machine body, and the replacement of the casing shall be determined according to the test results.

3.2 Maintenance project

3.2. 1 overhaul project

3.2. 1. 1 lift the bell jar for maintenance, or lift it out for maintenance;

3.2. 1.2 Maintenance of windings, leads and magnetic (electric) shielding devices;

3.2. 1.3 Maintenance of iron core and iron core fasteners (piercing screws, clamps, drawstrings, straps, etc.). ), pressure nail, pressure plate, grounding plate;

3.2. 1.4 Maintenance of oil tank and accessories, including shell, moisture absorber, etc.

3.2. 1.5 inspection of auxiliary equipment such as cooler, oil pump, water pump, fan, valve and pipeline;

3.2. 1.6 Maintenance of safety protection devices;

3.2. 1.7 Maintenance of oil protection device;

3.2. 1.8 Calibration of temperature measuring device;

3.2. 1.9 Maintenance and testing of operation control box;

3.2. 1. 10 Maintenance of non-excitation tap-changer and on-load tap-changer;

3.2. 1. 1 1 Leak test of all gaskets and components;

3.2. 1. 12 If necessary, dry the body insulation;

3.2. 1. 13 Treatment or oil change of transformer oil;

3.2. 1. 14 Clean the oil tank and spray paint;

3.2. Testing and debugging of1.15 overhaul.

Minor repair project

Deal with the found defects;

3.2.2.2 releases dirty oil from oil storage tanks;

3.2.2.3 overhauled the oil level gauge and adjusted the oil level;

3.2.2.4 Shuo Shuo cooling device: including oil pump, fan, oil flow relay, differential pressure relay, etc. , if necessary, purge the cooler tube bundle;

3.2.2.5 maintenance safety memory device: including oil storage tank, pressure relief valve (safety airway), gas relay, quick-acting oil pressure relay, etc.

3.2.2.6 overhauled the oil protection device;

3.2.2.7 overhauls temperature measuring devices, including pressure thermometers, resistance thermometers (winding thermometers) and rod thermometers.

3.2.2.8 overhauled and debugged the voltage regulating device, measuring device and control box;

3.2.2.9 checks the grounding system;

3.2.2. 10 Repair all valves and plugs, check all seals and deal with oil leakage;

3.2.2. 1 1 Clean the oil tank and accessories and touch up the paint if necessary;

3.2.2. 12 Clean, insulate and inspect the conductive joint (including the bushing general cap);

3.2.2. 13 Measure and test according to relevant regulations.

3.2.3 Temporary maintenance project

Can be determined according to the specific situation.

3.2.4 For the maintenance of old and new transformers, it is suggested to make improvements with reference to the following items.

3.2.4. 1 Strengthen the mechanical strength of the fuel tank;

The grounding device in 3.2.4.2 body is changed into lead wire and ground wire;

3.2.4.3's safe airway is changed to a pressure relief valve;

3.2.4.4 high-speed oil pump changed to low-speed oil pump;

Improvement of 3.2.4.5 oil level meter:

3.2.4.6 oil storage tank is equipped with sealing device;

3.2.4.7 gas relay is equipped with bellows joint.

4 Preparation before maintenance

4. 1 Consult the archives to understand the operation status of the transformer.

4. 1. 1 Defects and anomalies (accidents) found in operation, and the number and situation of export short circuits;

4. 1.2 load, temperature and accessory operation;

4. 1.3 Consult the summary report and technical files of the last overhaul;

4. 1.4 refer to the test records (including oil test and chromatographic analysis) to understand the insulation status;

4. 1.5 Check the oil leakage position and mark it;

4. 1.6 Test before overhaul to determine additional maintenance items.

4.2 Prepare technical organization measures plan for overhaul project.

Its main contents are as follows:

4.2. 1 personnel organization and division of labor;

4.2.2 Construction projects and progress;

4.2.3 Construction scheme of special projects;

4.2.4 Technical measures and on-site fire prevention measures to ensure construction safety and quality;

4.2.5 List of main construction tools, equipment and main materials;

4.2.6 Draw the necessary construction drawings.

4.3 Construction site requirements

4.3. 1 transformer maintenance work, if conditions permit, should be arranged in the maintenance room of power plant or substation as far as possible;

4.3.2 When there is no maintenance room at the construction site, the transformer can also be maintained at the site, but waterproof, moistureproof, dustproof and fireproof measures must be taken. At the same time, attention should be paid to keeping a safe distance from live equipment, preparing sufficient construction power supply and lighting, and arranging oil storage capacity, placement of large machines and tools, dismantling accessories and reasonable arrangement of fire fighting equipment.

5 Disassembly, maintenance and assembly of transformer

5. 1 Disassembly and maintenance

5. 1.65438+

5. 1.2 After the oil is partially drained, remove the auxiliary devices such as shell, lifting seat, oil storage tank, cooler, gas relay, oil purifier, pressure relief valve (or safety airway), header and thermometer. , and check whether the oil level indicator is correct when discharging oil from the oil storage tank.

5. 1.3 Drain all oil and dispose of it.

5. 1.4 Dismantle the operating lever of the tap-changer without excitation; For disassembly methods of various on-load tap changers, please refer to Operation and Maintenance Guide of On-load Tap Changers. Remove the middle waist flange or the connecting bolt of the big cover palace after the bell cover (or valve body).

5. 1.5 Check the car body condition, fasten all parts and test the insulation.

5. 1.6 Replace the sealing rubber gasket, repair all valves, and clean and repair the iron core, winding and oil tank.

5.2 assembly

5.2. 1 Replace the bell jar (or shell), and inject oil as required after fastening the bolts.

5.2.2 Install the casing after proper oil drainage, and install the internal lead for secondary oil injection.

5.2.3 Install accessories such as cooler.

Integral seal test.

5.2.5 Add oil to the specified oil level.

5.2.6 Conduct electrical and oil tests after overhaul.

5.3 Precautions during disassembly, maintenance and assembly.

5.3. 1 The disassembled bolts and other parts shall be cleaned, classified and properly kept, and repaired or replaced if damaged.

5.3.2 When disassembling, disassemble the small instrument and bushing first, then disassemble the large parts, and assemble them in the reverse order.

5.3.3 After the cooler, pressure relief valve (or safety air duct), oil purifier and oil storage tank are removed, they shall be sealed with cover plates, and qualified transformer oil shall be injected into the boss with current transformer (or other moisture-proof sealing devices shall be adopted).

5.3.4 Wearable parts such as casing, oil level gauge, thermometer, etc. After dismantling, it should be properly kept to prevent damage and moisture; Capacitor bushing should be placed vertically.

5.3.5 After assembly, check the valves of cooler, oil purifier and gas relay, and open or close them as required.

5.3.6 Exhaust the vent holes on the upper part of the casing riser, the upper pipe hole cover, the cooler and the oil purifier for many times until the exhaust is completed, and then re-seal and wipe off the oil stain.

5.3.7 When disassembling the operating lever of the tap changer without magnetization, the position of the tap changer shall be recorded and marked; When disassembling the on-load tap changer, the tap changer should be placed in the middle position (or the position specified by the manufacturer).

5.3.8 All components of the assembled transformer shall be intact.

5.3.9 Do a good job of on-site recording.

5.4 Lifting and handling during maintenance

5.4. 1 Lifting Work and Precautions

5.4. 1. 1 tea lifting should have a clear division of labor, with a special person in charge and a unified signal;

5.4. 1.2 Choose lifting tools according to the importance of transformer bell (or body), including crane, wire rope, lifting ring, U-shaped lifting ring, jack and sleeper.

5.4. 1.3 Before hoisting, dismantle all kinds of connections that affect the hoisting work;

5.4. 1.4 If the crane body is bound, the relevant bolts of the crane body should be fastened first;

5.4. 1.5 When lifting the whole transformer or bell jar (body), wire ropes should be hung on special lifting devices respectively, and gaskets should be placed at the four corners; When lifting about 100mm, stop to check the suspension and binding, and continue lifting after confirming reliability;

5.4. 1.6 When hoisting, the included angle of the steel wire rope should not be greater than 60, otherwise a special spreader or wire rope sleeve should be adopted;

5.4. 1.7 When hanging back or falling back to the bell jar (or body), the four corners should be tied with cables and supported by special personnel to maintain stability;

5.4. 1.8 The lifting or landing speed should be even, and the center of gravity should be well grasped to prevent tilting;

5.4. 1.9 When lifting or falling back to the bell jar (or box), keep a certain gap between the high and low voltage side leads, tap-changer bracket and the box wall to prevent damage to the box;

5.4. 1. 10 When the bell jar (or body) cannot move after lifting and needs to stay in the air, measures such as support should be taken to prevent falling;

5.4. 1. 1 1 When lifting the casing, its inclination should be basically the same as that of the casing lifting seat, and it should be tied with cables to prevent the porcelain bottle from being damaged by dumping;

5.4. 1. 12 When lifting with a truck crane, check the stability of the support, pay attention to the angle of the boom, the safe distance between the swing range and the adjacent live equipment, and supervise it by designated personnel.

5.4.2 Handling work and matters needing attention

5.4.2. 1 Understand the structure and bearing capacity of roads, subgrade, bridges, culverts and tunnels along the way, reinforce them when necessary, and contact the local railway department in advance when crossing important railway crossings.

5.4.2.2 knows the height of obstacles such as overhead power lines and communication lines along the way, and eliminates air obstacles to ensure safe passage.

When 5.4.2.3 transformer is transported in the factory (station) or in long-distance transportation, it should be bound and fixed firmly to prevent impact, vibration, inclination and damage to parts; The steering inclination is not greater than15 in the long axis direction and10 in the short axis direction; If a special pallet (raft) is used for traction and handling, the traction speed shall not be greater than 100m/h, and if the main transformer roller is used for handling, the traction speed shall not be greater than 200m/h (or as specified in the manufacturer's manual).

When 5.4.2.4 uses a jack to lift (or lower) the transformer, it should be supported at the designated part of the oil tank to prevent deformation; Jack should be placed vertically; The contact between the top of the jack and the fuel tank should be padded with wooden boards to prevent slipping.

When using jack to lift (or drop) the transformer in 5.4.2.5, it should be padded with wood squares and boards when lifting (or dropping) to prevent the jack from suddenly falling down and dumping; If jacks are used on both sides of the transformer, and both sides cannot rise (or fall) at the same time, they should take turns to work alone. Pay attention to the height difference between the two sides of the transformer to prevent the transformer from tilting. The loaded jack shall not be loaded for a long time, and shall be watched by special personnel from beginning to end.

When carrying 5.4.2.6 transformer with rolling bar, the traction center of gravity should be placed below the center of gravity of the transformer, and a special support plate should be placed at the bottom of the transformer. In order to increase the stability during handling, the length of the special support plate should exceed the length of the transformer, and both ends should be made into wedges to facilitate the placement of the roller frame; When transporting large transformers, steel belts should be added at the bottom of special supporting plates to enhance their robustness.

When 5.4.2.7 uses special trays and rolling frames to carry and load transformers, the channels should be filled and sleepers should be staggered. In order to facilitate the roller rolling, the joints of sleepers should be transferred from sleepers with slightly higher joints to sleepers with slightly lower joints in the direction of transformer. When the transformer rotates, the angle should be adjusted by the roller frame to prevent the roller from popping up and hurting people.

In 5.4.2.8, in order to keep sleepers flat, the bottom of sleepers can be properly padded with boards with different thicknesses.

When using the sliding national record group traction transformer in 5.4.2.9, the staff should stand in a proper position to prevent the wire rope from loosening or breaking and hurting people.

5.4.2. 10 transformer should check the direction of high and low voltage sides before handling and loading and unloading to avoid changing direction when it is installed in place.

5.4.2. 1 1 Nitrogen charging transformer shall be equipped with pressure monitoring instrument and nitrogen charging bottle to ensure that the transformer always keeps positive pressure during handling, the nitrogen pressure shall be kept at 0.0 1~0.03MPa, the dew point shall be below -35℃, and the nitrogen purity shall be no less than 99.99%.

(2005-06-25)

Integral assembly

Preparation and requirements before overall assembly

6.2. 1. 1 Before assembly, thoroughly clean the cooler (radiator), oil storage tank, pressure relief valve (safety airway), oil pipe, lifting seat, shell and all components and parts. Use qualified transformer oil to flush the components and parts in direct contact with the oil.

6.2. 1.2 The attached oil and water pipelines must be thoroughly cleaned, and there shall be no welding slag and other sundries in the pipelines, and inspection records shall be made.

6.2. 1.3 Metal mesh is not allowed to be installed in the oil pipeline to avoid the metal mesh rushing into the oil tank, and nylon mesh is generally used.

6.2. 1.4 Before installing the fuel tank, the foreign matters and dirt inside, box and bottom of the fuel tank must be cleaned up.

6.2. 1.5 Parts with installation marks, such as gas relay, tap changer, high and medium pressure bushing or high seat, relief valve (or safe airway) lifting seat, etc., shall be assembled according to the installation marks.

6.2. 1.6 Prepare a complete set of gaskets and sealants.

6.2. 1.7 Prepare qualified transformer oil.

6.2. 1.8 Clean the refueling equipment, vacuumizing equipment and pipelines; The newly used pipeline should also be washed first to remove the release agent from the pipeline.

put together

6.2.2. 1 Replace the bell jar (or shell);

When installing components in 6.2.2.2, it shall be carried out according to the manufacturer's "Shipping and Installation Instructions";

If there is a locating piece at the top of 6.2.2.3 oil tank, it should be located and sealed according to the combined dimension drawing and technical requirements;

For transformers made in 6.2.2.4 without rising slope, the gas relay side of the oil storage tank should have a specified rising slope on this basis;

The root of 6.2.2.5 transformer lead should not be stretched, twisted and bent;

6.2.2.6 For high-voltage leads, the wrapped insulating cone part must enter the equalizing ball of the bushing to prevent deformation;

6.2.2.7 must check whether the connecting rod of the nonmagnetic tap changer has been inserted into the fork of the tap changer before installing the bushing, and adjust it to the required tap position;

Transformer oil should be injected into each thermometer base in 6.2.2.8;

6.2.2.9 assembles the disassembled groups and components according to the outline dimension drawing (assembly drawing) of the transformer, in which the oil storage tank, moisture absorber and pressure relief valve (safety air duct) can be temporarily dismantled, and the connecting flange is sealed with a cover plate; Installation requirements and precautions shall be carried out according to the "Installation Instructions" of each group of components.

6.3 Drainage and refueling

6.3. 1 General provisions for oil drainage and refueling

6.3. 1. 1 Check and clean the oil tank, oil drum, pipeline, oil filter, oil pump, etc. And keep them clean and dry, free of dust, impurities and moisture.

6.3. 1.2 When discharging oil, the vent holes of transformer and oil tank must be opened, and the vent holes should be connected with a dry air device to prevent moisture from invading.

6.3. 1.3 When the oil in the oil storage tank does not need to be drained, the valve under the oil storage tank can be closed. Drain all transformer oil from the oil tank.

6.3. 1.4 Oil in the oil chamber of on-load tap changer shall be pumped out separately.

6.3. 1.5 Before filling oil into the strong oil-cooled transformer, the differential pressure relay on the water cooler and the plug on the oil purifier pipeline should be turned off.

6.3. 1.6 The exhaust pipe can be installed by using the valve on the main box cover or the valve on the gas relay header. The on-load tap changer should be connected with the main body, and the pressure of the main body should be balanced, and at the same time, it should take time to inject oil. After oil injection, it should be taken out and returned to normal.

6.3. 1.7 When filling oil into the transformer oil tank, it should pass through the pressure oil filter (vacuum oil filter is suitable for 220kV transformer).

Figure 1 Schematic Diagram of Vacuum Oil Filling Connection

1- oil tank; 2, 4, 9, 10- valve; 3- pressure oil filter or vacuum oil filter; 5- transformer; 6- vacuum gauge; 7- check valve; 8- vacuum pump

Vacuum oiling

220kV transformer must be vacuum oiled, and other equipment should also be directly oiled when conditions permit. Vacuum oil injection shall comply with the manufacturer's regulations or be carried out by the following methods. See figure 1 for the connection diagram.

Check the strength of the oil tank by vacuum test. In general, the local elastic deformation should not exceed twice the thickness of the tank wall, and the tightness of the vacuum system should be checked.

Operation method:

6.3.2. 1 vacuumize at a uniform speed, and after reaching the specified vacuum degree and keeping it for 2h, start to inject oil into the transformer oil tank (generally, the evacuation time is 1/3 ~ 1/2 exposure time), and the oil injection temperature should be slightly higher than the body temperature;

When 6.3.2.2 is about 200mm away from the top of the box, stop injecting oil into the transformer at a speed of 3~5t/h and continue pumping for more than 4h.

6.3.2.3 transformer oil replenishment: When the transformer is replenished after vacuum oil injection, oil needs to be injected through the oil injection pipe of the oil storage tank. Fuel injection from the lower throttle is prohibited. When injecting oil, the oil flow should be slowly injected into the transformer until the specified oil level is reached, and then let stand for 12h.

6.3.3 Oil replenishment of capsule oil storage tank

6.3.3. 1 Capsule venting: Open the vent hole at the upper part of the oil storage tank, fill the oil storage tank through the oil filler pipe until the oil comes out of the vent hole, and then close the oil filler pipe and vent hole;

6.3.3.2 drains oil from the throttle at the lower part of the transformer. At this time, air naturally enters the bladder of the oil storage tank through the dehumidifier until the oil level meter indicates the normal oil level.

6.3.4 Oil replenishment of diaphragm oil storage tank

6.3.4. 1 Before refueling, first set the magnetic oil level meter to zero, then open the air vent plug on the diaphragm, and then close the air vent plug;

6.3.4.2 injects oil into the diaphragm from the oil injection pipe until it is slightly higher than the specified oil level, and then opens the gas release plug again to fully eliminate the gas in the diaphragm until the oil overflows, and reaches the specified oil level after repeated adjustment;

6.3.4.3 found that when the oil mark in the lower gas collecting box of the oil storage tank showed air, the exhaust valve was used to exhaust gas.

When the normal oil level in 6.3.4.4 is low, the oil injection pipe at the lower part of the gas gathering box is connected to the oil filter to inject oil into the oil storage tank. When air is found in the gas collecting box during oil filling, stop oil filling, and open the exhaust pipe valve to exhaust, and so on until the oil level of the oil storage tank meets the requirements.

6.3.5 When the oil level gauge is equipped with a small tape, fill the oil storage tank.

6.3.5. 1 Before refueling the oil storage tank after the transformer overhaul, refuel the oil level gauge first. At this time, it is necessary to open the oil gauge breathing plug and the small bag chamber plug, slowly refuel from the oil gauge breathing plug seat with a funnel, and at the same time press the small adhesive tape by hand to exhaust all the air in the bag;

6.3.5.2 opened the oil drain bolt of the oil gauge, drained the excess oil in the oil gauge (you can see that the oil has an internal oil level), and then closed the plug of the capsule room. Pay attention to that the breathing plug of the oil gauge need not be screwed too tightly to ensure that the air in the oil gauge can breathe freely.

6.4 Overall seal test

After the transformer is installed, the overall sealing performance shall be checked as follows:

6.4. 1 static oil column pressurization method: the oil column height of 220kV transformer is 3m, and the pressurization time is 24h；; The oil column height of 35~ 1 10kV transformer is 2m, and the pressurization time is 24h；; The height of the oil column is calculated from the vault (or box cover).

6.4.2 Oil-filled pressurization method: 12h refueling pressure is 0.035MPa, and there should be no leakage or damage.

6.5 transformer oil treatment

6.5. 1 General requirements

6.5. 1. 1 The quality of transformer oil injected into the transformer after overhaul shall comply with the provisions of GB7665-87;

6.5. 1.2 After oil injection, take an oil sample from the oil drain valve (plug) at the bottom of the transformer for test and chromatographic analysis;

6.5. 1.3 According to the lowest temperature in the region, different brands of transformer oil can be selected;

6.5. 1.4 The transformer oil injected into the bushing shall also comply with the provisions of GB7665-87;

6.5. 1.5 When supplementing different brands of transformer oil, oil mixing test should be done first, and it can be used only after it is qualified.

Pressure oil filtration

6.5.2. 1 Use a pressure oil filter to filter water and impurities in the oil; In order to improve the speed and quality of oil filtration, the oil can be heated to 50~60℃.

Before using 6.5.2.2 oil filter, check whether the power supply, oil filter and filter screen are clean, whether there is dry oil filter paper in the polar plate, whether the rotation direction is correct, whether the shell is grounded, and whether the pressure gauge indicates correctly.

6.5.2.3 starter oil filter should first open the oil outlet valve, and then open the oil inlet valve, and the operation sequence is reversed when stopping; When installing the heater, start the oil filter first, and then put it into the heater after the oil circulates. When it stops, the operation sequence is reversed. The pressure of the oil filter is generally 0.25~0.4MPa, and the maximum pressure is not more than 0.5MPa.