| Geomagnetic disturbances caused by solar activity, resulting in ground potential at the surface, forms a very low frequency of geomagnetic induced current in the power grid. DC magnetic bias on transformer will due to GIC’s being Quasi-DC will result in harmonic and reactive power change and the vibration, noise and other secondary disasters. What’s worse, it may damage SVC, transformer, and shunt reactor equipment or even lead to power instability. Therefore, GIC can be regarded as the pacific reflection of grid magnetic storm.With the increase of grid’s scale, there occurs several cases of GIC violation in Guangdong Jiangsu and other places. And GIC has been a threat to the power grid in China. Therefore to establish a set of monitoring and assessment system to evaluate the risk of a substation before disaster and release real-time warning during monitoring is very important for those department who can make preparations to deal with the coming disaster.This paper firstly analyzed the factors that influences the GIC level. Lay a good foundation for picking risk assessment index for GIC. Then it presents a risk assessment method for power grid magnetic storm disaster based on ANN. The network is trained using the Shandong 500kV grid data. The method proved effective and objective after testing 5 substations. After that, this paper achieves the threshold value of several electrical parameters when GIC of different levels flow through the neutral point of the transformer by analyzing the mechanism of GIC’s influence on transformer and by consulting the results of past simulation experiments. Provide data support for the evaluation of GIC monitoring warning system. At last, this paper designs and develops the GIC monitoring assessment and warning system, use the system and the achieved data to evaluate the risk of a substation in advance and warn the danger during monitoring. |
