500kV砚都站断路器均压电容爆炸事故仿真分析及反措建议

针对一起500 kV变电站隔离开关操作过程中发生的触头关合不到位引起的断路器均压电容爆炸事故,运用电磁暂态软件ATP/EMTP编程建立了电弧重燃模型,从过电压以及能量积累两方面对事故原因进行了分析。结论认为事故是由系统通过电弧向均压电容与线路对地电容构成的串联电容多次充电引起的,均压电容两端电压波形包含基频、高频两个分量,长时间工频电压和操作电压的叠加作用效应最终导致均压电容发生绝缘击穿。根据仿真计算对事故反措提出了建议。

Simulating Study of an Explosion Accident of Circuit Breaker`s Grading Capacitor in Yandu Substation and Its Couter Measures

According to an explosion accident of 500 kV circuit breaker grading capacitors caused by insulation switch operating fault,simulated the arc multi-restrike process between the moving and static contact of isolation switch with electromagnetic transient software ATP / EMTP,and studied the factors of the accident from the view of overvoltage and energy accumulation respectively. Results indicated that the continued arc discharge between the two contacts of insulation switch can be equivalent to a repeatedly charging process by the power system to the series circuit formed by circuit breaker parallel capacitors and the line-to-ground equivalent capacitance of Yan-Xijia transmission line. The voltage waveform across the capacitor includes power-frequency and high-frequency components,and the insulation breakdown by the superimposed effects of long term frequency voltage and switching voltage. According to the simulation we presented the anti-accident measures and recommendations.