| Summary: | Geomagnetically induced currents (GICs) flowing through transformers affect their normal operation and can lead to accidents in power grids. The reactive power loss caused by GICs is called GIC-Q. At present, geomagnetic data are usually used to calculate GICs in research. These methods do not have real-time characteristics and cannot be used for real-time research on GICs. Response mechanisms for GICs in 1000 kV ultra-high voltage (UHV) transformers and for the effect of GIC-Q on large power grids are urgently required to prevent damage. Based on the principle of Kalman filter, this paper presents a model and method of calculating and analyzing GIC disturbance using the reactive power measured by wide area measurement systems (WAMS). The proposed method exhibits superior characteristics for real-time analysis and solves the problem of real-time shortage in GIC research. The model provides a theoretical calculation of GIC-Q disturbance in a 1000 kV autotransformer. Further, this method was verified according to the measured reactive power in three 1000 kV substations in Shandong Province and the measured geoelectric field at the Anqiu geomagnetic observatory station on September 8, 2017. The calculation results show that the reactive power measured by phasor measurement units (PMUs) can be effectively used to calculate and analyze GIC-Q in the transformers, which is significant to prevent disasters in the power grid caused by magnetic storms through dispatch and operation.
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