(1) Before the on-load tap changer tester is put into operation, the oil conservator should be checked, its oil level should be normal, there should be no oil leakage, the control box should be moisture-proof, a cycle of manual operation (i.e., a cycle of raising and lowering) should be performed, the gear indicator and counter should operate correctly, the locking at the limit position should be reliable, and the interlock between manual and electrical control should also be reliable.
(3) The electrical control of the on-load tap changer tester should be correct, the power supply can be adjusted, the terminals should be in good contact, the drive motor should rotate normally with correct direction, and the rated current of the fuse should be 2-2.5 times the rated current of the motor.
(5) When two on-load tap-changing transformers are operated in parallel, the tap changer is allowed to operate under 85% rated load current of the transformer; however, two tap changers cannot be operated continuously on one transformer, and a tap change operation on one transformer must be performed after the tap change operation on the other transformer is completed. Before a transformer with on-load tap changer and a transformer with off-load tap changer are operated in parallel, the tap position of the on-load tap changer must be adjusted to the same or similar position as the off-load tap changer, even if the secondary voltages of the two main transformers are the same or similar. When an on-load tap-changing transformer and an off-load tap-changing transformer are operated in parallel, it is strictly forbidden to adjust the tap changer.
a. Collect oil samples every 6 months for compression test. The oil pressure resistance value should not be less than 30 kV/2.5mm. When the oil pressure is between (25-30kV)/2.5mm, the automatic voltage regulator should be stopped. When the oil pressure is less than 25 kV/2.5mm, the tap changing operation should be stopped and oil replacement should be arranged in a timely manner. Oil should be replaced after 2-4 years of operation or when the number of tap changing operations reaches 5000 times.
<span style="color: rgb(51, 51, 51); font-family: " pingfang="" sc",="" "lantinghei="" "microsoft="" yahei",="" arial,="" 宋体,="" sans-serif,="" tahoma;="" font-size:="" 16px;"="">b. Check the core of the on-load tap changer tester head valve. After one year of new operation, or after 5000 tap changes. After 3x4 years of operation or when the cumulative number of adjustments reaches 10000x20000 times. However, imported equipment can be inspected according to the manufacturer's regulations, and the core inspection should be combined with the transformer overhaul.
