When is it not allowed to adjust the on-load tap changer of a transformer?

During the operation and maintenance of a transformer, the adjustment of the on-load tap changer (OLTC) needs to strictly adhere to regulations to ensure the safe and stable operation of the transformer. Here are several situations in which adjusting the OLTC is not permitted:

During transformer overload operation: Overloading can cause an increase in internal temperatures, and adjusting the tap changer at this time may lead to insulation aging of the transformer windings or even trigger a failure. However, in special circumstances, such as the need to temporarily adjust the tap changer to ensure grid stability, it should be done strictly according to regulations, and normal load should be restored promptly after adjustment.

When signals of frequent gas protection alarms from the OLTC are detected: Frequent gas protection signals indicate a possible internal fault in the transformer, and adjusting the tap changer is not allowed at this time.

When the transformer's OLTC oil gauge shows no oil or an excessively low oil level: Transformer oil is crucial for proper cooling and insulation, and a low oil level can lead to overheating and insulation problems. The oil level issue should be addressed before making any adjustments.

When the number of tap changes exceeds the specified limit: Excessive tap changes may indicate wear or overheating issues in the transformer windings or OLTC and require the transformer to be shut down for inspection and maintenance.

When the OLTC malfunctions: Malfunctions in the OLTC can lead to unstable output voltage from the transformer, affecting grid operation. Adjustments should only be made after troubleshooting and rectifying the OLTC malfunction.

LuShan, est. 1975, is a Chinese professional manufacturer specializing in power transformers and reactors for 49 years. Leading products are single-phase transformer, three-phase transformers, DC inductors, AC reactors, filtering reactor, expoxy resin high-voltage transformer and intermediate, high-frequency products. Our transformers and reactors are widely used in 10 application areas: rapid transit, construction machinery, renewable energy, intelligent manufacturing, medical equipment, coal mine explosion prevention , excitation system, vacuum sintering, central air conditioning.

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