Study On GIC Reactive Power Of 500kV Transformer With Multiple Geomagnetic Storms

The research of geomagnetically induced current(GIC)has made important progress in China,including the understanding of the differences in geoelectric field between low and high latitude,the mechanism of the power grid disasters of geomagnetioc storms in low latitude,and the secondary interference effects of GIC injected into transformers,ect.,which implies that it is urgent to study the prevention and control of power grid disaster of geomagnetic storm.This paper studies the algorithm of GIC reactive power of 500kV transformer against geomagnetic storms based on the PMU data.The main contents are as follows:(1)The basic theory of geomagnetic storm on transformers was studied,the generation process of GIC and its distribution path are analyzed,and the basic geoelectric field model based on geomagnetic data is introduced in Chapter 2.For more accurate calculation of 3D geoelectric field,a discrete format for solving transient Maxwell equations is proposed.This part provides a comparative method and comparative data for the follow-up study of GIC reactive effect.(2)The mechanism of secondary interference of transformers under effects of GIC is analyzed.Based on PMU data,the response models of fundamental reactive power and excitation current to GIC are established respectively,and a calculation method of GIC reactive power of transformer with PMU data is proposed,which is compared with the method based on the transformer parameters.The results show that the new method based on the PMU data to calculate the GIC effects is more directly and reliably compared with the previous methods.(3)The cases of multiple geomagnetic storms in 500kV substation in Yangquan,Shanxi are analyzed.The transformer response and the variation characteristics of reactive power and excitation current for multiple geomagnetic storms are discussed.And the paper makes a compare with the results of the method based on parameter K to verify the validity of the new model and algorithm.The results indicate that transformers GIC disturbance can be calculated availably by measurement data,which offer a foundation for GIC risk assessment and prevention.In this paper,the PMU data of the reactive power variation induced by geomagnetic storm is obtained for the first time.A calculation method of GIC reactive power of transformer based on PMU data is proposed,which can be used for the power grid operation and dispatching system,the analysis of reactive effect of transformer caused by geomagnetic storms,and the judgement of influence and harm of the transformer GIC reactive power,which is of great significance to prevent and control the geomagnetic storm disasters.