500kV串联电抗器对线路断路器开断能力的影响研究

在短路电流严重超标的地区合理地加装串联电抗器是降低局部地域短路电流水平的一种有效手段,但是线路加装串联电抗器后会影响线路断路器的正常开断。以500 k V鹏深双线串联电抗器工程为例,研究了串联电抗器对线路断路器开断能力的影响,研究结果表明:当串联电抗器装在线路一侧时会造成该侧线路断路器断口暂态恢复电压陡度超出标准规定值,致使其在开断短路电流过程中发生重燃而导致开断失败;在串联电抗器两侧并联电容器可降低暂态恢复电压陡度,对于鹏深双线串联电抗器工程建议上述电容值取为60 n F;装设串连电抗器后虽然增加了短路电流直流分量的时间常数,使短路电流中的直流分量衰减较慢,但由于短路电流幅值的显著降低,从而使得灭弧过程中电弧释放的能量并不高,不会影响断路器的开断。

Study on Influence of 500 kV Series Reactor on Interrupting Capability of Line Circuit Breaker

Reasonable installation of series reactor is an effect way to limit the short circuit current in the aera where the short circuit current is excessively large, but it can have an adverse effect on the normal breaking of line circuit.Taking the 500 kV Shenzhen-Pengcheng series reactor project as an example, the influence of series reactor on the interrupting capability of line circuit breaker is analyzed The results show that when the series reactor is installed on one terminal of the transmission line, the RRRV(rate of rise of restriking voltage) of line circuit breaker on the same side with the series reactor can exceed the standard, which could lead to breaking failure. Parallelly installing a capacitor with the series reactor can solve the above problem and a 60 nF capacitance is recommended for Shenzhen Pengcheng series reactor project. Although the DC component of the short circuit current is decayed slower when series reactor is installed, the line circuit breaker can still break safely due to the significant decrease of the amplitue of short ciruit current.