Study On The Influence Of High Speed Railway Load And Direct Current Disturbance On Power System

Locomotive load is supplied by traction network of high speed railway.For the power system,it is a three-phase unbalanced load,the biggest impact is negative sequence,it is disadvantageous to the power system in many aspects,including relay protection device,transformer,power lines,generators and motors,which will directly endanger the safe and stable operation of power system.But the DC interference of the traction power system may be caused by a variety of reasons,such as geomagnetic induced current(GIC)caused by geomagnetic disturbances,DC interference of DC grounding near the traction substation,DC interference of high speed rail in the normal operation of the power supply arm,grounding of electrical equipment.The research on negative sequence is to consider the three-phase voltage unbalance of the point of common coupling of the traction substation and the connected power system when high-speed train is in common operation.The paper research adopts the method of theoretical analysis and simulation research to calculate the negative sequence current and three-phase voltage unbalance of the 5 high speed railway traction power stations in Yanbian area.In the theoretical analysis,A mathematical model of high-speed railway traction power supply system with V/X connection mode is established,an analysis method of negative sequence for power system with V/X connection mode is proposed.In simulation calculation,use PSCAD/EMTDC which is an electromagnetic transient analysis program to to complete the calculation of the influence of 5 high speed railway traction station on the power system.The research results show that the influence of 5 high speed railway traction station on power system in Yanbian area is different,there is excessive phenomenon of the unbalanced voltage degree when the short circuit capacity of PCC point is small.Study on the DC interference of traction power supply system is to consider DC interference in power supply system,then carry out scientific experiments including putting forward the monitoring scheme of DC interference science experiment,completing the installation of interference monitoring device in traction substation and joint debugging of background data center,use obtained interference monitoring data and complete the study on the influence of DC disturbance on substation and traction power supply system.The analysis results show that the DC interference of the traction transformer,the rail,the upstream protection line and integrated grounding of traction network system are mainly caused by the interference of the high-speed railway train in the power supply arm and GIC caused by the geomagnetic disturbance,these DC disturbance will flow in the traction network and the integrated grounding grid system.