Inspection method for overheating of power transformer

1. If the instrument in operation indicates that the transformer is overloaded, if the indications of the phases in the three-phase transformer group are basically the same (may have several deviations), and the transformer and the cooling device have no signs of failure, it can be judged that the temperature rise is Caused by overload. It is necessary to strengthen the monitoring of the load, temperature and operating conditions of the transformer, and strive to reduce the overload multiplier and shorten the overload time.

2. If the cooling unit is not fully charged or faulty, it should be disposed of immediately to eliminate the malfunction. If the fault cannot be eliminated immediately, the transformer operating load must be reduced and operated according to the corresponding cooling device performance and load.

3. If the remote temperature measuring device sends an alarm signal and the indicating temperature value is high, and the field thermometer indication is not high, the transformer has no other fault phenomenon, which may be a fault alarm of the remote temperature measuring device. Such failures can be ruled out when appropriate.

4. If the temperature of one phase of the three-phase transformer group rises, which is significantly higher than the operating temperature of the same load and the same cooling condition before the phase, and the cooling device and the thermometer are normal, the overheating may be caused by the internal of the transformer. Due to some faults, the technician should immediately take samples for chromatographic analysis to further identify the fault. If the chromatographic analysis indicates that there is an internal fault in the transformer, or if the transformer is constantly rising in load and cooling conditions, the transformer shall be taken out of operation as specified in the on-site operating procedures.