Strong magnetic storm''''s influence on China''''s Guangdong power grid
中国广东电网的几次强磁暴影响事件

With the Yang-Huai power transmission system and other 500 kV long-distance transmission lines' coming into operation since 2001,unknown severe transformer vibration and increased noise have often been found in Shanghe of Jiangsu and Ling'ao of Guangdong.This paper gives a comparison of more than ten magnetic storms and measured transformer neutral current data since November,2004,and proved that the disturbances were caused by geomagnetically-induced current(GIC).On the 7th and 10th,November,2004,the maximal magnetic storm caused GIC in Ling'ao Nuclear Station was 47A and 55.8A,both larger than the transformer neutral DC level in HVDC's monopole operation,so,magnetic storms' instantaneous influence is larger than HVDC's.And the data show that GIC level in Guangdong Power Grid is higher than that of the Yang-Huai power transmission system,by initial analysis it's considered to be related with grid structure and coast effect etc.By now,the widely concerned 1000kV UHV power transmission system has begun constructing,and the UHV line's unit resistance will be at most half of the 500 kV line's,and in condition of longer transmission line,larger scale and single-phased transformer's adoption,the issue of magnetic storm's influences will be more urgent to be studied.