直流单极运行时谐波对并联电容器的影响

电力系统中实际运行情况表明,谐波问题是并联电容器安全运行的主要威胁。特别在直流单极运行时,交流变压器因为直流偏磁而使各次谐波电流剧增,这些谐波电流进入运行中的并联电容器并被放大,会导致电容器谐波过载,损坏电容器。某500 kV变电站的35 kV无功补偿电容器组就因为三-广直流单极运行而曾发生多次电容器爆炸事故。文中阐述了直流单极运行时各次谐波电流是如何产生的,然后分析了谐波被放大的原理、谐波对电容器组的危害,并详细分析了该500 kV变电站的无功补偿电容器组在三-广直流单极运行时发生爆炸的原因,最后提出几点抑制谐波电流放大的措施。

Influence of Harmonic on Shunt Capacitor in HVDC Monopolar Operation

It's indicated from the actual operation of power system that harmonic problem is the primary threat to the safe operation of shunt capacitor.Especially,during HVDC is in monopolar operation,the harmonic current in AC transformer would be increased due to the DC magnetic biasing and be amplified after entering in the operating shunt capacitor.Finally,the shunt capacitor would be damaged.A certain 35 kV reactive power compensating capacitors at 500 kV substation had been exploded in succession because the San-guang HVDC system was monopolar operation.In this paper,the principle of harmonic current coming from monopolar operation of HVDC is introduced,and then the amplified principle and harm to the shunt capacitor are analyzed.Also,reason of the blast of reactive power compensating capacitors at 500kV substation during monopolar operation in San-guang HVDC is analyzed in detail.Finally,some measures are proposed to restrain the amplification of harmonic current.