特高压半波长交流输电系统断路器瞬态恢复电压特性研究

Characteristics of Transient Recovery Voltage of Circuit Breakers in UHV AC Half-wavelength Transmission System

半波长输电线路特性与常规线路不同，在线路发生短路故障时，其断路器开断瞬态恢复电压（TRV）特性与常规线路有很大差别。为此，建立了特高压半波长交流输电系统仿真模型，研究了半波长线路在不同位置发生短路故障时，断路器开断的短路电流及TRV特性，分析了相关影响因素；研究了抑制半波长线路断路器TRV的措施。研究结果表明，半波长线路断路器开断短路电流特性和TRV特性受故障点位置影响较大，在距断路器2500-3000km的远端发生接地故障时，断路器开断短路电流水平较高，可能超过断路器出口故障时的短路电流水平，断路器开断远端故障时的TRV的峰值和上升率均较高，超过了现有标准中断路器试验允许值。半波长线路沿线装设金属氧化物避雷器（MOA）后，MOA抑制了接地故障时的过电压，有助于降低TRV水平，但在部分位置故障时TRV仍然超过了允许值。采用沿线装设MOA和断路器装设分闸电阻的措施后，可以将特高压半波长线路断路器TRV限制在现有标准范围内。

Because of the unique characteristics of half-wavelength transmission lines, the transient recovery voltage（TRV） characteristics of the circuit breaker are different from those of the conventional lines when short circuit fault occurs on the line. We established a simulation model of UHV half-wavelength AC transmission system. Moreover, we studied the characteristics of short-circuit current and TRV of circuit breaker during interrupting short-circuit fault at different posi- tions, analyzed the relevant influencing factors, and proposed the limitation measures of TRV. The study results show that the short-circuit current and TRV of circuit breaker for half-wavelength line are greatly affected by the position of the fault. When the ground fault occurs at the remote end of 2 500~3 000 km from the circuit breaker, the short-circuit current of the circuit breaker is high and may exceed the short circuit current during the circuit breaker terminal fault. Also, the TRV peak and the rate of rise of TRV are much higher than the allowable values of the circuit breaker test in the current standard. Metal oxide arrester（MOA） installed along the half-wavelength line helps to reduce the TRV, by suppressing the overvoltage on the line generated by the ground fault. However, the TRV still exceeds the allowable value in some cases. With the measure of opening resistor installed on circuit breaker together with MOA along the line, the TRV can be lim- ited to the allowable value of current standard.