金丝接地极偏磁治理对浙江电网GIC的影响

Influence of Jinsi Grounding Electrode Magnetic Bias Control on the GIC of Zhejiang Power Grid

直流输电工程建设中大量采用电容隔离装置治理偏磁电流,这种治理方法会导致电网GIC(地磁感应电流)的重新分布,使电网发生地磁暴事故或灾害的风险增加。针对溪洛渡—浙西±800 kV直流工程金丝接地极近区的电网,建立了500 kV电网的GIC模型,根据1989年3月13日、2004年11月7日及2017年9月7日GMD(地磁扰动)数据,分别计算了电容隔离装置投入前后电网的GIC水平。研究结果表明,采用电容隔离装置治理后,500 kV某变电站变压器中性点的GIC从10 A水平增大为90 A水平,使该变电站成为GIC事故高风险站点。

Capacitive isolators,widely used to control magnetic bias current in construction of Ultra-high voltage direct current(UHVDC)transmission projects,may lead to the redistribution of geomagnetically induced current(GIC)in power grid and multiple the risk of geomagnetic storms and disasters.The GIC model of the 500 kV power grid is established for the power grid near the Jinsi grounding electrode,which is the grounding electrode of Xiluodu-West Zhejiang±800 kV UHVDC project.A GIC model for 500 kV power grids is built according to the power grid adjacent to Jinsi grounding electrode of the±800 kV Luoxidu-Zhexi DC transmission project.Based on the geomagnetic disturbance(GMD)data of March 13,1989,November 7,2004,and September 7,2017,the GIC levels of the power grid before and after the capacitive isolators were put into operation.The results show that the GIC of 500 kV Ninghai substation transformer neutral point increases from 10 A to 90 A after capacitor isolators were adopted,and 500 kV Ninghai station,therefore,became highly risky.