特高压断路器预击穿对合闸空载GIS母线操作过电压的影响

针对近几年国内特高压GIS设备启动调试过程中在断路器合闸冲击空载母线时造成绝缘击穿事件,参考特高压GIS断路器特性,建立电磁暂态仿真模型,研究了断路器预击穿对特高压GIS母线快速暂态过电压的影响,得到以下结论:①在断路器合闸空载GIS母线时,不考虑断路器预击穿,则2%统计过电压为1.58 p.u.,考虑预击穿现象后,其最高可达1.8 p.u.;②根据仿真计算,特高压断路器合闸空载GIS母线暂态过电压的首波上升时间约为0.3μs,小于标准雷电冲击波的上升时间;③断路器合闸空载GIS母线暂态过电压虽没有超过GIS设备的操作冲击耐受水平,但可激发GIS母线的隐性缺陷,引起绝缘事件。根据仿真计算结果和国内外对GIS设备绝缘特性的研究,对预防此类绝缘击穿事件提出了意见和建议,对交流特高压GIS设备的设计和绝缘事故预防具有一定的参考价值。

Effect of UHV Circuit Breaker Pre-breakdown on Switching Overvoltage when Closing Unloaded GIS Bus

In the light of insulation breakdown events caused by UHV circuit breaker closing unloaded GIS bus when commissioning process of UHV GIS equipment in recent years, in this paper, effects on switching overvoltage when closing unloaded GIS bus caused by the pre.breakdown of the circuit breaker is researched. And the results suggest: 1) if without considering the pre-breakdown of the circuit breaker, the 2% statistics overvoltage is 1.58 p.u., while with considering the pre-breakdown, the overvoltage would be up to 1.8 p.u.;2)The rise time of the first transient overvoltage wave is 0.3μs,less than the standard lightning impulse rising time;3)The fast transient overvoltage did not exceed switching impulse protective level of UHV GIS equipments, but the hidden defects of equip. ments would be excited easily with the effect of the overvoltage, even cause insulation accident. Based on the simulation results and the researches on the insulation characteristics of GIS equipment at home and abroad, this paper puts forward some opinions and suggestions are put forward to prevent the insulation breakdown, and the research conclusions of this paper can be used as reference for the design of AC UHV GIS equipment and insulation accident prevention.