Test circuit for mechanical switch for direct current circuit breaker

Abstract

The invention relates to a test circuit for a mechanical switch for a direct current (DC) circuit breaker. The test circuit comprises positive and negative connection ends for connecting a mechanicalswitch sample, and a DC power supply module, an oscillating circuit and a surge voltage generating circuit which are connected in parallel, wherein the DC power supply module, the oscillating circuitand two parallel ends of the surge voltage generating circuit are correspondingly connected to the positive and negative connection ends. The test circuit provides a stable DC current to the mechanical switch, and provides the mechanical switch with the rated current stress and port thermal stress before breaking; provides the mechanical switch with the high-frequency current stress at the breaking moment to enable quenching of arc when zero-crossing during the mechanical switch breaking process; and generates a transient impulse voltage satisfying certain waveform parameters, which is equivalent to the tolerant transient voltage stress between the fractures of the mechanical switch during the breaking process, thereby realizing the dynamic insulation test of the mechanical switch under rated operating conditions, and the equivalence of the rated current stress before the breaking, the high-frequency current stress during the breaking, and the transient voltage stress after the breaking between the ports. The test circuit is simple in method and strong in stress equivalence.

Description

technical field [0001] The invention relates to a test circuit of a mechanical switch for a direct current circuit breaker, belonging to the technical field of high voltage direct current transmission. Background technique [0002] The hybrid DC circuit breaker based on mechanical switches and power electronic switches as the core components has the characteristics of fast breaking speed, low operating loss, flexible and reliable control, etc., and is also a popular product in the current industry research. However, the mechanical switch in the hybrid DC circuit breaker will withstand the transient voltage before the stroke is in place during the short-circuit current or DC current breaking process. The detailed operating conditions in the system are: under normal operating conditions, the mechanical switch conducts the rated DC current of the system, and the temperature of the switch contacts is in a hot operating state; when the DC circuit breaker receives the breaking com...

AI Technical Summary

Problems solved by technology

[0010] The purpose of the present invention is to provide a test circuit of a mechanical switch for a DC circuit breaker, which is used to solve the problem of dynamic insulation characteristic testing in the breaking process of a mechanical switch of a DC circuit breaker under thermal stress and current stress conditions

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