±500 kV换流站交流滤波断路器闪络故障分析及外绝缘特性

Analysis of Flashover Accident and External Insulation Characteristics of AC Filter Circuit Breaker in ±500 kV Convertor Station

交流滤波器的频繁投切会造成断路器承受较大直流残压,同时受环境因素的影响容易导致断路器发生闪络故障,严重威胁高压直流系统的安全稳定运行。针对某±500 kV换流站发生的交流滤波断路器闪络事故进行了分析研究,结合录波数据和现场试验确定故障原因为恶劣的气象条件加上电源侧直流电压与交流侧电压的叠加引起断路器外绝缘闪络和相间闪络。为解决交流滤波断路器外绝缘降低的问题,开展了断路器外绝缘闪络特性试验研究以及提高外绝缘污闪电压措施试验研究,发现污闪电压会随着盐密、灰密的增加明显降低,而安装增爬裙或喷涂PRTV涂料能够明显提高污闪电压。根据试验结论提出了相应的防止断路器污闪的措施,取得了良好的应用效果。

Frequent input and elimination for AC filter will superpose the circuit breaker a large DC residual voltage, and the influences of environmental factors easily lead to circuit breaker flashover faults, which will cause a serious threat to the safe and stable operation of HVDC system. We analyzed a 500 kV converter AC filter circuit breaker flashover accident by combining with the wave recording and field test. It is found that harsh weather conditions and the superposition between DC voltage on power side and the voltage on AC side will cause the circuit breaker interrupter insulating flashover and interphase flashover. For solving the reducing of AC filter circuit breaker insulation, we experimentally analyzed the circuit breaker external insulation flashover characteristic and improvements in the external insulation pollution flashover voltage. It is found that the pollution flashover voltage will significantly reduce with the salt density and ash dense increasing, and the installation of the creeping increasing skirt or spraying PRTV coating can significantly enhance the pollution flashover voltage. According to the test results, the corresponding measures to prevent the circuit breaker pollution flashover are put forward, and the good application results are obtained.