特高压固定串补火花间隙拒触发事故分析及解决方案

当前超、特高压固定串补用火花间隙的试验及考核均以工频和倍频故障电流为主,基本未考虑故障电流含有直流分量的情况。分析了1000 kV特高压南阳站一起特高压固定串补用火花间隙拒触发事故,认为本次线路故障电流中直流分量幅值较大导致火花间隙触发控制回路中电压测量传感器磁饱和,导致火花间隙触发控制单元未能正确测量出串补过电压水平而拒触发。提出维持现状的南阳站现场临时解决办法。解决该问题的根本途径是提高火花间隙触发控制回路中电压测量传感器在直流电流下的抗饱和能力。根据对火花间隙触发控制回路中元器件的试验室研究结果,提出减小该电压传感器励磁电流、增大铁芯面积以及降低原边和副边匝数以提高传感器在直流电流下的抗饱和能力的解决方案。

Analysis of spark gap refusal trigger accident in UHV fixed series compensation and corresponding solutions

Fault current for test and assessment of spark gap used in UHV(Ultra High Voltage) and EHV(Extra High Voltage) fixed series compensation is mainly based on power frequency and double frequency, DC component in fault current is not considered. A spark gap refusal trigger accident of UHV fixed series compensation in 1000 kV Nanyang substation is analyzed, which shows that the large amplitude of DC component in fault current leads to the magnetic saturation of voltage measurement sensor in spark gap trigger control circuit, so the spark gap trigger control circuit unit fails to measure the series compensation overvoltage level correctly and refuses to trigger. Temporary solution is proposed to maintain the status quo, which is accepted in Nanyang substation. The fundamental way to solve this problem is to improve the anti-saturation ability under DC current of voltage measurement sensor in spark gap trigger control circuit. According to the results of laboratory research on the components of spark gap trigger control circuit, the solutions of reducing the excitation current, increasing the area of the iron core and reducing the turns of the primary and secondary side of the voltage sensor are proposed to improve its anti-saturation ability of the sensor under DC current.