高压直流开断的三电源合成试验方法

Synthetic Test Method with Three Power Sources for HVDC Circuit Breaker

开断试验的等价性是高压直流断路器合成试验的基本要求。针对直流系统常见的平波电抗器对直流开断后暂态恢复电压(TRV)的持续作用,提出一种由电流源、换流源和恢复电压源组成直流合成试验的三电源回路拓扑,尝试在直流合成试验回路中增加独立的恢复电压源,在TRV上升阶段与避雷器吸能阶段补偿试验系统能量,提高TRV幅值与避雷器吸能时间,提供TRV持续作用和能量吸收对开断等价性的检验。以基于换流技术的机械式直流真空断路器开断过程为背景,参考交流合成试验回路的等价性原则,探讨直流断路器合成试验方法及其等价性条件。采用电磁暂态仿真软件完成直流试验回路建模与直流开断过程仿真,分析了基本满足等价性条件的试验参数设置。搭建了60 kV/16 kA三电源合成试验回路系统,初步测试结果表明:三电源合成回路及其试验方法可基本满足直流开断试验的等价性条件,TRV幅值平稳且持续作用时间可达10 ms以上。

The equivalence of interrupting test is the fundamental requirements of synthetic tests for high-voltage direct-current circuit breakers.As a result of the continuous action of transient recovery voltage(TRV)which is caused by the smoothing reactor in DC system,a synthetic test circuit topology with three power sources was presented,which include current source,commutation souce and recovery voltage source.The equivalence was taken to use an independent recovery voltage source for simulating this condition.Recovery voltage souce was used to compensate the enery of test circuit in the rising stage of TRV and energy absorption stage of surge arrester,and increase TRV amplitude and energy absorption time of surge arrester.According to the background of interrupting process in the mechanical DC vacuum circuit breaker,which was based on commutation technology,the equivalence principles of AC synthetic test circuit were taken as references.The synthetic test method of DC circuit breaker and its equivalence conditions were also discussed.Electromagnetic transient simulation software was used to simulate the modeling of synthetic test circuit and the interrupting process of DC system.Parameters for the basic equivalence test circuit were analyzed.A 60 kV/16 kA synthetic test system with three power sources was built.The preliminary test results show that this synthetic test circuit can basically satisfy the equivalence condition of DC interrupting test.The amplitude of TRV is stable and its duration can be prolonged to over 10 ms.