特高压串补线路断路器短路电流过零延迟特性及对策

Zero-crossing Delay Characteristics of Short Circuit Current Passing Through Circuit Breakers of UHV Series Compensated Lines and Countermeasures

特高压线路加装串补使得线路发生故障时流经断路器的短路电流特性与无串补线路相比存在差别。受故障工况及串补布置方式、过电压保护措施等因素影响,特高压串补线路回数为双回及以上时,一回线故障时流经断路器的短路电流可能存在过零延迟,与无串补或单回串补线路相比更加突出,对断路器开断不利,需要加以抑制。该文仿真研究特高压串补线路断路器短路电流的过零延迟特性,并结合串补金属氧化物限压器(metal oxide varistors,MOV)、放电间隙的动作状态,采用时、频域解析方法,建立串补装置的等效模型,探讨串补线路短路电流过零延迟的产生机理,研究分析典型影响因素,并提出对策建议。研究成果为特高压串补的规划设计、断路器设备选型提供一定参考。

The installation of series capacitors （SCs） on UHV AC lines makes the short circuit current characteristics during line fault different from that of no SC lines. Provided by the factors such as fault conditions, SC arrangement, SC overvoltage protection measures and so on, it may exists short-circuit current zero-crossing delays when the circuit breakers （CB） clear line fault for the line circuit number is 2 and above. It is much severe than no SC lines and single circuit lines with SC, which can affect the normal switching of the CBs and need suppression. This paper studied the zero-crossing delay characteristic of line CBs short.circuit current for UHV SC lines by simulation. Also, combined with operation situation of MOV （Metal Oxide Varistors） and gap of SC, the equivalent circuit models for SC were built and the generating mechanism of short-circuit current zero-crossing delay was discussed in the time domain and frequency domain analysis method. The typical influencing factors of zero-crossing delay were studied, and the corresponding were proposed. The results provides technical basis for the planning and design of UHV SCs, so as to the equipment specification of UHV CBs.