Series-resonance voltage-withstanding partial discharge test device adopting fixed duty ratio square wave frequency conversion power supply

Abstract

The invention relates to a series-resonance voltage-withstanding partial discharge test device adopting a fixed duty ratio square wave frequency conversion power supply. The device comprises the 1:1 fixed duty ratio square wave frequency conversion power supply. After an excitation transformer adjusts a voltage, the power supply applied the voltage to a sample cable. The sample cable is connected in parallel to a partial discharge collector so as to collect partial discharge signals. The partial discharge signals are transmitted to a partial discharge analysis system so as to analyze. A switching point of a change-over switch of the frequency conversion power supply is always kept at 0 degree and 180 degree, and the positions are a voltage zero point where a sine wave is output; and during partial discharge measurement, the point can be shielded so that a measurement result is not influenced. The partial discharge signals can be continuously collected during alternating current voltage withstanding so that credibility and accuracy of partial discharge measuring signals are increased. Through continuous collection, a noise reduction effect of the partial discharge signals can be greatly increased so that fault positioning of a partial discharge point is easy and accurate.

Description

technical field [0001] The invention relates to the field of electric devices, in particular to a series resonance withstand voltage partial discharge test device using a square wave frequency conversion power supply with a fixed duty ratio. Background technique [0002] Before the power line is handed over and put into operation or after maintenance, it must be inspected and evaluated for its insulation state. Among them, the AC withstand voltage test is a must-do test, and the partial discharge measurement is developed in recent years. A more advanced detection method for early diagnosis and development trend prediction function. [0003] There are generally three boosting methods for the withstand voltage test: external application method, multi-frequency induction method and series resonance method. The series resonance method is to use the reactor and the test object to form an LC resonant circuit, and make the test circuit reach the resonance state through frequency m...

AI Technical Summary

Problems solved by technology

But for partial discharge measurement, the boost source must be non-interfering, otherwise it will affect the accuracy and reliability of the measurement. For this reason, most current partial discharge tests use linear power amplifier mode without partial discharge variable frequency power supply, but The power supply is not suitable for low efficiency, high heat generation, and large volume. Although the partial discharge test system using a square wave variable frequency power supply has high power supply efficiency and small size, the switching tube is turned on and off due to the unstable duty cycle during voltage regulation. The burr interference generated during the time will affect the partial discharge

Images