Assemble the parts on the transformer tank cap

Reinstall the repaired parts or replacement parts on the fuel tank cap, and replace the original sealing gaskets with gaskets of good quality, oil resistance, and stable chemical performance. Generally, the gasket should be compressed about 1/3 of the original thickness after compaction.

(1) Assemble the casing. For 0.4kV low-voltage bushings, use the positioning nails welded on the lower end of the conductive rod and the nuts on the upper end to clamp the upper and lower porcelain bushing strings on the transformer box cover. For 10kV high voltage bushings, there is a fixing table in the middle, which is clamped on the transformer cover with pressure nails. For 60kV and above oil-filled bushings, when assembling, they should be assembled in the reverse order of disassembly and inject qualified insulating oil. , Conduct insulation test. When assembling, it is required that the conductive rod should be in the middle of the porcelain sleeve and must not be skewed. When tightening the flange screws, the gap between the porcelain sleeves should be kept even to prevent local force from cracking the porcelain sleeve. When tightening the oil level gauge gland screws, prevent glass damaged. In order to prevent oil oxidation, the surface of the glass oil level gauge should be painted with silver powder, and there should be a rubber sealing gasket at the junction of the casing and the cover, which should be assembled tightly to prevent oil leakage. The vent screw hole on the top of the casing should be opened when filling oil. Drain the air in the casing. After the oil overflows, tighten the blocking screw to prevent the air in the casing from being broken down under the action of a strong electric field.

For 110~220kV oil-impregnated paper capacitor bushings, the middle flange of the porcelain sleeve should be preheated to 80~90℃ before assembly, and kept for 3-4 hours to remove moisture, and then proceed in the reverse order of disassembly. Assembly. When assembling, it is required that the temperature of the capacitor core should be 10~15℃ higher than the air temperature, and all parts should be clean and intact. The casing has good sealing requirements, no oil leakage, and the oil level meets the standard.

(2) Assemble the tap changer. For the unloaded tap changer, after the switch operating mechanism cover and the installation round nut are removed, the sealing gasket is inserted into the opening of the box cover, so that the positioning nail and the upper card board of the box cover are touched, and then tighten the fixing nut to adjust Just after positioning. After assembling, the mechanical rotation is required to be flexible, the rotating shaft is tightly sealed, the fixing is reliable, and there is no jamming. Appropriate amount of lubricating oil should be added to the rotating part. All the firmware of the switch should be tightened without looseness. The upper indication position of the switch is consistent with the actual contact position of the lower part, which shall be verified by electrical tests.

For on-load tap-changers, there are many types produced by China and imported from abroad. When assembling, they should be assembled in accordance with the requirements of the manufacturer’s instructions.

(3) Assemble the oil conservator (oil pillow) and gas relay. For ordinary oil conservator (oil conservator), hoist the oil conservator (oil conservator) on the cabinet foot of the bracket, insert the bolts, and put on the nuts. Re-adjust and tighten.

For other types of oil conservator (oil pillow) such as capsule type, follow the manufacturer’s instructions and assemble in the reverse order of disassembly. All assembled oil conservator (oil conservator) shall be well sealed and free of leakage. The rising slope of the connecting pipe between the oil tank and the oil conservator (oil conservator) and the rising slope of the top lamp along the direction of the gas relay shall be in accordance with Require.

(4) Assemble the respirator. For a newly installed respirator, unscrew the end cover, remove the gasket, and then reinstall the cover. For the overhauled respirator, check whether the oil level in the cover meets the oil level mark: the silica gel or calcium oxide in the respirator should leave a gap of 10~15mm under the top cover, and the silica gel should appear blue before breathing. The respirator is installed under the flange connecting the oil conservator (oil pillow) and the respirator, and it is required to tighten it so that the respirator cannot shake.

(5) Assemble the thermometer. The structure of the transformer thermometer is shown in the figure. For plug-in mercury thermometers, they are often installed on the low pressure side of the top cover of the fuel tank. The thermometer seat on the top of the box should be cleaned first, and transformer oil should be injected, and then the thermometer should be inserted and tightened, as shown in the figure.

Thermometer assembly drawing

Assemble the parts on the transformer tank cap
(A) Mercury thermometer assembly; (b) Signal thermometer
1- Upper cover: 2- Outer cover: 3- Thermometer scale: 4- Steel flange 5- Screw: 6, 7- Fuel tank cover; 8- Temperature measuring cylinder: 9- Temperature measuring tube: 10- Pipe joint: 11- Metal Hose: 12-terminal, 13-pointing pointer: 14-fixing hole: 15-pointer: 16-shell, 17-adjusting screw, 18-dial

(6) Install the connection between the winding lead of the transformer and the bushing, and the connection with the tap changer. When wiring, be sure to align the original mark and place it in the original position when it was disassembled. The wiring is required to be correct, and the lead wires should be insulated from each other.