HVDC站内直流转换开关避雷器动作电流监测装置设计与应用

Design and Application of Action Current Monitoring Device of DC Transfer Switch Arrester in HVDC Station

直流转换开关是高压直流输电系统中的关键设备。直流转换开关内并联的避雷器组在开关动作后需要快速吸收大量能量。但是,多柱并联结构的避雷器普遍存在氧化锌电阻片能量吸收不均的问题,导致低阻抗的单柱氧化锌发生热崩溃击穿故障。在线同步采样多柱避雷器动作电流是及时发现和更换特性退化的避雷器阀组、保障设备安全和系统稳定运行的迫切要求。为实现动作电流的同步采样,研究了一种无线通信的动作电流监测装置,具有高精度同步、高采样率、短距离无线通信和非破坏安装等优势。实测动作电流数据表明,监测装置能够及时发现电流不均匀情况,避免避雷器被击穿引起非计划停运,提高系统运行稳定性。

DC transfer switch is the key equipment in HVDC transmission system.The lightning arrester group connected in parallel in the DC transfer switch needs to quickly absorb a large amount of energy after the switching action.However,the multi-pillar parallel structure lightning arrester generally has the problem of uneven energy absorption of ZnO resistors,which leads to the thermal collapse and breakdown of low-impedance ZnO single-pole.Online synchronous sampling of the action current of the multi-pillar arrester is an urgent requirement for timely detection and replacement of degraded arrester valve groups to ensure the safety of equipment and the stable operation of the system.In order to realize synchronous sampling of action current,a wireless communication action current monitoring device was studied,which has the advantages of high precision synchronization,high sampling rate,short distance wireless communication,non-destructive installation and so on.The measured action current data show that the monitoring device can detect the current unevenness in time,avoid the unplanned outage caused by the breakdown of the lightning arrester,and improve the operation stability of the system.