Capacitor partial discharge detection circuit

Abstract

A capacitor partial discharge detection circuit is used for detecting high-voltage capacitor partial discharge signals. The technical solution is: the detection circuit includes a self-balancing coupling transformer, an inductor and a capacitor, the self-balancing transformer is composed of an iron core and three coils, the first coil and the second coil have the same structure, and the head end of the first coil is The unbalanced input terminal is connected to the test power supply through the capacitor of the test product, and its tail end is connected to the tail end of the second coil through the inductor, and connected to the first end of the second coil through the capacitor. The first end of the second coil is connected to the signal common end, and the third The partial discharge signal output from both ends of the coil is connected to the partial discharge tester. The invention can work in two test modes of unbalanced and balanced. In both test modes, the partial discharge pulse current signal can be separated when the impedance magnetic core is close to zero magnetic flux, and the balanced coupling transformer will not appear saturation phenomenon. , so the magnitude of the main loop current will not affect the PD detection sensitivity.

Description

technical field [0001] The invention relates to a circuit for detecting a partial discharge signal of a high-voltage power capacitor, which belongs to the technical field of detection. Background technique [0002] In the production process of high-voltage power capacitors, it is necessary to test their insulation performance by detecting the amount of discharge inside them. At present, there are two main methods for detecting the internal discharge of high-voltage power capacitors, one is the ultrasonic detection method, and the other is the pulse current method. The disadvantage of using the ultrasonic detection method is that the quantitative error is large, and sometimes it cannot accurately measure the internal discharge of the capacitor. The discharge value of the discharge value; the pulse current method is to connect the capacitor of the test product in series with the primary coil of the coupling transformer and then connect it to the AC test power supply for the te...

AI Technical Summary

Problems solved by technology

At present, there are two main methods for detecting the internal discharge of high-voltage power capacitors, one is the ultrasonic detection method, and the other is the pulse current method. The disadvantage of using the ultrasonic detection method is that the quantitative error is large, and sometimes it cannot accurately measure the internal discharge of the capacitor. The discharge value of the discharge value; the pulse current method is to connect the capacitor of the test product in series with the primary coil of the coupling transformer and then connect it to the AC test power supply for the test, and judge the internal discharge of the capacitor under test by detecting the pulse current signal in the secondary coil of the transformer

The disadvantage of this method is that the leakage current of the capacitor is very weak relative to the test current flowing through it, and it is not easy to detect, and when the test current in the series circuit is large, it will saturate the coupling transformer, resulting in detection Decreased sensitivity, or even undetectable

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