What Key Tests Should Be Performed On The Transformer During Operation?

What key tests should be performed on the transformer during operation?
To ensure stable operation of the transformer, the following tests must be performed regularly:
(1) Temperature test. The upper oil temperature is a key indicator for measuring the status of the transformer. Its upper limit should not exceed 85°C, that is, the temperature rise should not exceed 55°C. Transformers are usually equipped with special temperature measuring devices to monitor this indicator.
(2) Load measurement. In order to make full use of the transformer and reduce power loss, its power supply capacity must be actually measured during the peak power consumption period of each season. The measurement can be carried out directly using a clamp ammeter. The target current value should be controlled within the range of 70-80% of the rated current of the transformer. Exceeding this range indicates overload and needs to be adjusted in time.
 

(3) Voltage measurement. The regulations stipulate that the voltage variation range should be within ±5% of the rated voltage. If it exceeds this range, it should be adjusted through the tap to ensure that the voltage meets the regulations. Usually, the secondary coil end voltage and the end user end voltage are measured separately with a voltmeter.
(4) Insulation resistance measurement. In order to prevent insulation aging and accidents, the insulation resistance of the transformer must be measured regularly. Before the measurement, the transformer should be stopped and the insulation resistance value should be measured with a megohmmeter, which should be no less than 70% of the previous measured value. For low-voltage coils, a megohmmeter with a voltage level of 500 volts can be used for measurement.