地磁感应电流对电网安全稳定运行的影响

Influences of Geomagnetic Induced Currents on Security and Stability of Power Systems

太阳黑子异常活动而导致的具有准直流特性的地磁感应电流(geomagnetic induced current,GIC)的峰值远远高于变压器允许承受的直流量,已引起国内外多个电网相继发生电气设备受损和电网崩溃的事故。分析了GIC产生的机制,以及GIC致使变压器出现直流偏磁的原因。文中指出通过变压器的直流偏磁,GIC可能对交流电网的设备和电网的安全稳定运行构成威胁。详细分析了不同类型高压直流输电GIC存在的可能性,指出长距离高压直流输电只有在2种运行方式下,直流线路中才会出现GIC;正常运行时,该直流GIC不会危及直流输电的运行。最后提出了开展GIC对交直流系统安全稳定运行研究工作的建议。

The solar wind arising from the eruption of abnormal movement of solar sunspots makes earth surface potential （ESP） abnormal and the peak values of geomagnetic induced currents （GIC） in transmission lines, which are induced by abnormal ESP and possess quasi-DC characteristic, are much higher than the allowable DC currents sustained by power transformers. This phenomena cause sequent damages of power equipments in power systems home and abroad as well as collapse of power systems. The producing mechanism of GIC and the reason leading to DC bias in transformer due to GIC are analyzed. It is pointed out that GIC could give the danger to power equipments as well as to secure and stable operation of AC power grids. The possibility of existence of GIC in different types of HVDC power transmission lines is analyzed in details and it is pointed out that for long-distance HVDC power transmission the GIC could produce only under mono-polar ground return operation mode and bipolar operation mode, and during normal operation this GIC will not jeopardize the operation of HVDC power transmission system. Finally, some suggestions for the research on the influences of GIC on secure and stable operation of HVAC and HVDC power transmission systems are proposed.