On-load tap-changer tap-changer failure and maintenance On-load tap-changer tap-changer fault is caused by what causes?
A: It is caused by the following reasons:
(1) The transition resistance in the auxiliary contact is broken through during the switching process.
(2) The tap switch is not tightly sealed, and the water inlet causes a short circuit between the phases.
(3) As the contact roller is stuck, the tap changer is stopped in the transitional position, resulting in a short circuit between the turns and burning out.
(4) The tap changer tank is short of oil.
(5) The fault current is encountered during voltage regulation.
On-load tap-changer transformer tap-changer maintenance contents and requirements (1) Before the on-load tap-changer is put into operation, it is necessary to inspect the oil-filled pillow. The oil level should be normal, there should be no leakage oil, and the control box should be protected from moisture. Manual operation of a cycle (ie, lifting a cycle), gear indicator and counter should be correct action, the limit position of the lock should be reliable, manual and electric control interlock should also be reliable.
(2) Gas protection of on-load tap-changer, heavy gas input trip, light gas signal. This is the same as the gas protection requirements of the transformer body. We usually call the main gas relay "big gas" and the on-load tap-changer gas relay "small gas." The gas relay should be installed in a position where it is safe to bleed air. After the newly commissioned on-load tap-changer gas relay is put into operation, the operating personnel should deflate gas when necessary (gas in the cylinder).
(3) The electric control of the on-load tap-changer should be correct, the power supply is reliable, and the contact terminals are in good contact. The drive motor rotates normally and the steering is correct. The rated current of the fuse is set at 2 to 2.5 times the rated current of the motor.
(4) The on-load tap-changer power control circuit, the electric operation button installed on the control panel, and the button on the on-load tap-changer control box installed on the transformer body should be intact, the power indicator and the gear position indicator The device should be in good condition and the electrical blocking at the extreme position should be reliable.
(5) The current locking device shall be provided for the electric control circuit of the on-load tap-changer, the setting value of which is 1.2 times the rated current of the transformer and the return coefficient of the current relay is greater than or equal to 0.9. When auto-regulation is used, there must be an action counter on the master change control screen. The secondary disconnection of the voltage transformer of the automatic voltage regulator should be correct and reliable.
(6) On-load tap-changer after new or overhaul shall operate with a remote electric operation button and manual equipment on the transformer at the main control room when the transformer is idling, and try to operate a cycle, gear and voltage, etc. The indication is correct, and the electrical locking of the limit position is reliable, and the tap position that can be adjusted to the schedule can be operated with a load, and monitoring can be strengthened.
(7) The attendant automatically adjusts the pressure according to the voltage curve and voltage signal sent by the dispatcher. Every operation should carefully check the voltage and current changes of the tap operation (one count per adjustment) and make a record.
(8) Two transformer on-load switch testers When the on-load tap-changer is operated in parallel, it is allowed to perform tap change operation under the transformer's 85% rated load current. However, two tap changing operations cannot be performed continuously on a single transformer. A tap changeover operation of another transformer is required after the tap change operation of one transformer is completed. Before an on-load tap changer and a no-load tap changer are operated in parallel, the tap changer of the on-load tap-changer must be adjusted to the same or similar position as the on-load tap changer, even if two The secondary voltage of the main transformer is the same or similar. When the on-load tap-changer and the no-load tap-changer are operated in parallel, it is forbidden to adjust the tap-changer.
(9) When on-duty switches are on duty for on-duty personnel, inspections should be carried out according to the inspection requirements. Before and after operation, attention should be paid to the presence of bubbles in the gas relay.
(10) When the gas relay of the on-load tap-changer in operation signals or the oil change of the transformer of the on-load switch tester of the tap-changer, the operation is prohibited and the power disconnector is opened.
(11) During operation, the heavy gas protection of the on-load tap-changer gas relay shall be tripped. When light gas moves frequently, the on-duty personnel should make records and report the schedule, stop the operation, analyze the cause and deal with it in time.
(12) On-load tap-changer oil quality supervision and inspection cycle: 1 The oil sample should be taken every six months during the operation to carry out pressure test once, and the oil pressure resistance value should not be lower than 30kV/2.5mm. When the oil pressure is between (25～30kV)/2.5mm, the automatic pressure regulator controller should be stopped. If the oil pressure is lower than 25kV/2.5mm, pressure regulating operation should be stopped and oil change should be arranged in time. Change oil when running for 2-4 years or changing operation up to 5000 times. 2 on-load tap-changer body hanging core inspection: After one year of new commissioning, or tap changer switch 5000 times; run 3 to 4 years or accumulative adjustment times of 10000 to 20000 times, but the imported equipment can be carried out according to the manufacturer's regulations , In conjunction with the overhaul of the transformer for core inspection.
(13) When checking the on-load tap-changer core, the transition resistance value shall be tested and consistent with the value of the manufacturer.
(14) When the electric operation occurs "linked" (ie, one or more taps, commonly referred to as "glide", will appear when the operation is performed once), the second point should appear on the gear indicator of the main change control screen. Immediately after the position of the connector, press the "Emergency Trip" button to cut off the power of the drive motor, then manually operate to the position of the tap that meets the requirements at the operation box, and notify the maintenance personnel to deal with it in time.
(15) When the voltage is too low or too high and several on-load tap-changers are required to adjust the taps to meet the requirements, the adjustment should be made one step at a time, ie each press of "N+1" or "N-1" Press the button for a pause of 1 minute. When a new number appears on the gear indicator, press the button again. Repeat the above process in order to achieve the final goal.
A: It is caused by the following reasons:
(1) The transition resistance in the auxiliary contact is broken through during the switching process.
(2) The tap switch is not tightly sealed, and the water inlet causes a short circuit between the phases.
(3) As the contact roller is stuck, the tap changer is stopped in the transitional position, resulting in a short circuit between the turns and burning out.
(4) The tap changer tank is short of oil.
(5) The fault current is encountered during voltage regulation.
On-load tap-changer transformer tap-changer maintenance contents and requirements (1) Before the on-load tap-changer is put into operation, it is necessary to inspect the oil-filled pillow. The oil level should be normal, there should be no leakage oil, and the control box should be protected from moisture. Manual operation of a cycle (ie, lifting a cycle), gear indicator and counter should be correct action, the limit position of the lock should be reliable, manual and electric control interlock should also be reliable.
(2) Gas protection of on-load tap-changer, heavy gas input trip, light gas signal. This is the same as the gas protection requirements of the transformer body. We usually call the main gas relay "big gas" and the on-load tap-changer gas relay "small gas." The gas relay should be installed in a position where it is safe to bleed air. After the newly commissioned on-load tap-changer gas relay is put into operation, the operating personnel should deflate gas when necessary (gas in the cylinder).
(3) The electric control of the on-load tap-changer should be correct, the power supply is reliable, and the contact terminals are in good contact. The drive motor rotates normally and the steering is correct. The rated current of the fuse is set at 2 to 2.5 times the rated current of the motor.
(4) The on-load tap-changer power control circuit, the electric operation button installed on the control panel, and the button on the on-load tap-changer control box installed on the transformer body should be intact, the power indicator and the gear position indicator The device should be in good condition and the electrical blocking at the extreme position should be reliable.
(5) The current locking device shall be provided for the electric control circuit of the on-load tap-changer, the setting value of which is 1.2 times the rated current of the transformer and the return coefficient of the current relay is greater than or equal to 0.9. When auto-regulation is used, there must be an action counter on the master change control screen. The secondary disconnection of the voltage transformer of the automatic voltage regulator should be correct and reliable.
(6) On-load tap-changer after new or overhaul shall operate with a remote electric operation button and manual equipment on the transformer at the main control room when the transformer is idling, and try to operate a cycle, gear and voltage, etc. The indication is correct, and the electrical locking of the limit position is reliable, and the tap position that can be adjusted to the schedule can be operated with a load, and monitoring can be strengthened.
(7) The attendant automatically adjusts the pressure according to the voltage curve and voltage signal sent by the dispatcher. Every operation should carefully check the voltage and current changes of the tap operation (one count per adjustment) and make a record.
(8) Two transformer on-load switch testers When the on-load tap-changer is operated in parallel, it is allowed to perform tap change operation under the transformer's 85% rated load current. However, two tap changing operations cannot be performed continuously on a single transformer. A tap changeover operation of another transformer is required after the tap change operation of one transformer is completed. Before an on-load tap changer and a no-load tap changer are operated in parallel, the tap changer of the on-load tap-changer must be adjusted to the same or similar position as the on-load tap changer, even if two The secondary voltage of the main transformer is the same or similar. When the on-load tap-changer and the no-load tap-changer are operated in parallel, it is forbidden to adjust the tap-changer.
(9) When on-duty switches are on duty for on-duty personnel, inspections should be carried out according to the inspection requirements. Before and after operation, attention should be paid to the presence of bubbles in the gas relay.
(10) When the gas relay of the on-load tap-changer in operation signals or the oil change of the transformer of the on-load switch tester of the tap-changer, the operation is prohibited and the power disconnector is opened.
(11) During operation, the heavy gas protection of the on-load tap-changer gas relay shall be tripped. When light gas moves frequently, the on-duty personnel should make records and report the schedule, stop the operation, analyze the cause and deal with it in time.
(12) On-load tap-changer oil quality supervision and inspection cycle: 1 The oil sample should be taken every six months during the operation to carry out pressure test once, and the oil pressure resistance value should not be lower than 30kV/2.5mm. When the oil pressure is between (25～30kV)/2.5mm, the automatic pressure regulator controller should be stopped. If the oil pressure is lower than 25kV/2.5mm, pressure regulating operation should be stopped and oil change should be arranged in time. Change oil when running for 2-4 years or changing operation up to 5000 times. 2 on-load tap-changer body hanging core inspection: After one year of new commissioning, or tap changer switch 5000 times; run 3 to 4 years or accumulative adjustment times of 10000 to 20000 times, but the imported equipment can be carried out according to the manufacturer's regulations , In conjunction with the overhaul of the transformer for core inspection.
(13) When checking the on-load tap-changer core, the transition resistance value shall be tested and consistent with the value of the manufacturer.
(14) When the electric operation occurs "linked" (ie, one or more taps, commonly referred to as "glide", will appear when the operation is performed once), the second point should appear on the gear indicator of the main change control screen. Immediately after the position of the connector, press the "Emergency Trip" button to cut off the power of the drive motor, then manually operate to the position of the tap that meets the requirements at the operation box, and notify the maintenance personnel to deal with it in time.
(15) When the voltage is too low or too high and several on-load tap-changers are required to adjust the taps to meet the requirements, the adjustment should be made one step at a time, ie each press of "N+1" or "N-1" Press the button for a pause of 1 minute. When a new number appears on the gear indicator, press the button again. Repeat the above process in order to achieve the final goal.
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