Monitoring and Modeling Geomagnetically Induced Currents in Power Grids of China

Geomagnetically induced currents (GIC) flowing in the power grids threaten the safe operation of the power system. The GIC disturbing events in Chinese power grids show the necessity of knowing the level of GIC. This paper introduces two aspects of work on the subject, which are monitoring and modeling of GIC, respectively. Firstly, the author introduces the detecting and monitoring technology of GIC in the power grids, and gives examples of GIC monitoring data which expose that the GIC amplitude can be quite large even if in low latitude areas. Secondly, the author introduces the model of calculating GIC and, based on the Plane Wave Method, presents a discrete algorithm according to which software has been developed to calculate the Earth surface electric Held. The data of a strong magnetic storm at the Zhaoqing Geomagnetic Observatory are used to calculate the electric field and GIC at the Ling'ao nuclear power plant. The measured data and the calculated results agree well, and the method is thus applicable to assessing GIC in power grids.