摘要
2015年4月28日,±500 k V溪洛渡直流输电工程双回金属回线运行时因线路故障相继闭锁,其中牛从甲极1重启动成功,牛从乙极2重启动不成功,随后在对牛从乙极2解锁试送功率上升过程中,牛从乙接地极母线差动保护动作,牛从乙极2闭锁,检查发现送端昭通换流站牛从乙极2中性母线F4避雷器故障损坏。经分析,本次直流控制保护均正确动作,避雷器故障发生于牛从乙极2重启动过程中。结合故障电压波形和避雷器解体结果分析,得出本次中性母线避雷器故障原因是同塔双回直流系统连续故障期间中性母线避雷器长时承受过电压,且注入能量总和超出其设计能量耐受能力,最终导致电阻片发生热崩溃。拟在保证避雷器保护水平不超过现有设备绝缘水平的前提下,提高中性母线避雷器的参考电压,并合理调整配合电流,将过电压倍数由原来1.415倍降低为1.2倍,同时拟通过在各并联避雷器上加装高精度采样的避雷器动作电流及电压在线监测及录波装置,以实现对避雷器动作时的能量耐受情况以及并联避雷器的均流特性分析,及时发现设备隐患和异常。
On April 28, 2015, ±500 kV Xiluodu HVDC project for line fault locking up one after another, Pole 1 restart successfully,but pole 2 restart failed. In the process of Pole 2 unlock and power up, Grounding pole bus differential protection action,and inspection found Pole 2 neutral bus F4 arrester damaged in Zhaotong Converter Station. By the analysis of the DC control protection are correct action, and arrester failure occurred in Pole 2 restart process. The fault voltage waveform and disintegration of arrester are combined and analyzed, it is concluded that the cause of the neutral bus arrester fault is during the continuous fault of double towers DC system, neutral bus arrester withstand Long-term overvoltage, and the total injected energy beyond its design energy tolerance, eventually lead to thermal collapse in the varistor. It is recommended to ensure the arrester protection level under the premise of not more than the existing equipment insulation level, improve the sending reference voltage on the neutral- bus arrester, and reasonably adjust the current, Preliminary estimates overvoltage multiple can be reduced from 1.415 times to 1.2 times, and by proposed on each arrester parallel unit with high precision high frequency sampling arrester leakage current and voltage on-line monitoring and record device, in order to realize the energy resistance situation of lightning arrester moves and parallel flow characteristics analysis of lightning arrester, timely detection equipment hidden dangers and exceptions.
出处
《电瓷避雷器》
CAS
北大核心
2017年第4期132-135,共4页
Insulators and Surge Arresters
关键词
中性母线避雷器
热崩溃
能量耐受
过电压倍数
动态均流特性
neutral-bus arrester
thermal collapse
energy resistance
overvoltage multiple
dynamic flow characteristics
