550kV双断口交流滤波器断路器暂态恢复电压仿真

Simulation of Transient Recovery Voltage of 550 kV AC Filter Breaker with Double Breaks

直流换流站安装有不同滤波次数的交流滤波器(AC filter,ACF),ACF断路器频繁操作以满足换流站无功补偿的需要,在开断大容性电流后断口承受交直流混合电压的共同作用,断口直流分压按电阻分布,而断口等效电阻受外界环境的影响,因此断口承受的电压可能会超过其绝缘能力。以国内典型的550 kV瓷柱式双断口小组滤波器断路器为例,利用PSCAD建立暂态恢复电压(TRV)仿真电路模型,对影响断口TRV分布的环境因素进行了仿真,仿真结果显示外界环境因素(如湿度、污秽、干湿不均等)对断口TRV影响较大,在特定环境条件下当断口绝缘电阻下降较大且两断口电阻值差异较大时,断口最大TRV值会接近或超过规范要求值,从而可能造成断口电弧重燃或闪络故障。

AC filters（ ACFs） for different harmonics are installed in HVDC stations,they switch on and off very often with circuit breakers for reactive power compensation. ACF breakers bear transient recovery voltages（ TRV） comprising AC and DC voltages after switching off large capacitive current,because the DC voltage component is decided and divided by resistance which is influenced by the ambient environment of porcelain breaker external insulation,the TRV may exceed the insulation requirement. Using a typical 550 k V AC filter procelain breaker with two breaks used in HVDC stations as an example,a simulation model of TRV is established based on PSCAD to simulate the influencing factors of TRV. The simulation results showthat the ambient environment,such as humidity,dirt and dry zone,can seriously affect the TRV of breaks. With specific ambient environment conditions,when the break resistance decreases and the diffence between the two break resistances is large,the maximum break TRV may approach or even exceed the theshhold value,which will result in breaker restrike or flashover.