In the power system, there are two ways to measure partial discharge: one is power outage measurement; the other is online monitoring.

For power failure measurement: According to various physical and chemical phenomena caused by partial discharge, people have proposed many methods for measuring partial discharge, which can be summarized into two categories, one is electrical measurement. The other is the non-electrical measurement method.

(1) Electrical measurement method

This is a measurement method based on various electrical information generated by partial discharge. At present, there are mainly:

1. Pulse current method

Due to the charge exchange generated during partial discharge, a pulsating voltage appears at both ends of the test product, and a pulse current appears in the circuit connected to the test product. Therefore, the pulse signal representing the partial discharge can be obtained on the detection impedance in the circuit, thereby performing Measurement.

2. Radio Interference Law.

Due to partial discharge, a pulse signal with a wide frequency spectrum is generated. Therefore, radio interference can only be used to measure partial discharge pulse signals.

3. Discharge energy method

Because partial discharge is accompanied by energy loss, a bridge can be used to measure the discharge energy of a cycle, or a microprocessor can be used to directly measure the discharge power.

(2) Non-electrical measurement method

This is a method of measuring the discharge of selenium by using various non-electrical information generated by partial discharge. At present, there are mainly:

1. Ultrasonic method

Ultrasonic detection technology is used to measure the ultrasonic waves generated by partial discharges, so as to analyze the location and extent of the discharge.

2. Photometry

The photomultiplier technology is used to measure the light generated by partial discharges to determine the location of the discharge, the beginning of the discharge and its development process.

3. Decomposition (or production) method of measuring pomelo

Under the effect of partial discharge, various decomposition products or products may appear, and various chromatographic and spectral analysis can be used to determine the various decomposition products or products, so as to infer the degree of partial discharge. Such as measuring the composition and quantity of gas in transformer oil to infer the degree of partial discharge in the transformer.