Research On The Effects Of Geomagnetic Storms On The Characteristics Of High-speed Railway Traction Transformer

With the rapid development of high speed railway in China, its related security research has gradually become the core issue in the field of high speed rail. Especially in recent years, domestic and foreign experts and scholars on the impact of space weather is particularly focused. Geomagnetic storm as an extreme space weather, when they occur, the long distance transmission lines will be affected, at home and abroad has occurred many times the power accidents caused by geomagnetic storms. The high speed railway traction power supply system is similar to the electric power system; and China’s high-speed rail construction time is short, has not yet experienced the test of sunspot maximum period; as the ground traction power supply system of the traction transformer, the influence of geomagnetic storms may be greater. Therefore, the study of the influence of the geomagnetic induced current on the characteristics of the traction transformer has a strong forward-looking and important social significance.This paper firstly introduces the high-speed rail traction power supply system, the analysis of the geomagnetic storms, GIC intrusive traction mechanism of power supply system. In this paper, the equivalent resistance model of the traction power supply system is established, and the theoretical amplitude estimation formula of GIC is derived. Into the relevant parameters, get the range of GIC estimation. In order to determine whether there is a real GIC in traction transformer, this paper designs the GIC monitoring device, and uses Multisim simulation software to build the core of the monitoring device current conditioning circuit, which verifies the feasibility of the circuit. In this paper, the device is put into operation, and the first measurement of GIC in the field of high speed railway in China has been completed. By comparing the monitoring data with the space weather forecast, the accuracy of the monitoring data is verified. Thus it is confirmed that there is indeed a GIC in the traction transformer.In this paper, based on Matlab to build a single line, all parallel AT power supply system model, through the simulation analysis to determine the scope of the change of GIC, verify the theoretical calculation formula of GIC. The paper puts forward the concept of the equivalent resistance asymmetry of traction network. The no-load test model of the traction transformer is built, and the distortion rate of the excitation current of the traction transformer is increased with the increase of the GIC amplitude, but also with the increase of the asymmetry of the impedance. The effect of GIC on the excitation characteristics of traction transformer is proved.Based on Ansoft Maxwell to build the finite element model of the traction transformer, traction transformer core flux and magnetic density, magnetic flux leakage, core loss and winding loss increases with the increase of the amplitude of the GIC, also with increase of the equivalent impedance of the asymmetric degree increased. The effect of GIC on the electromagnetic characteristics of traction transformer is proved.Aiming at the influence of GIC on the traction transformer, this paper introduces the corresponding suppression measures, and emphatically introduces the two methods of the compensation current of the grounding wire series capacitor and the additional winding. The simulation results show that the measure has good inhibitory effect.