Composite Load Equivalent Modeling of Traction Power Supply System

In recent years, China's high-speed railway from zero to one, from weak to strong, has achieved a leapfrog development. However, the access of a large number of electrified railways is a further challenge for the safety, stability and economy of the power grid, but the current research on the composite load characteristics of traction substations is relatively weak. In this paper, a detailed simulation model of CRH2 emu is built firstly. Based on the analysis of the operation characteristics and load composition of the traction power supply system, a composite load equivalent model of high-speed railway traction power supply system - the mechanism load model of “constant impedance parallel induction motor” is proposed. Finally, the Matlab/Simulink was used to compare the simulation results of the detailed simulation model with those of the equivalent model, and the results showed that the obtained power curve was highly consistent, which verified the accuracy and practicability of the equivalent load model.

I. Introduction

High-speed railway is an indispensable part of the national economy, while the access of a large number of electrified railways has become an important factor affecting the safety and stability of power grid because of its strong impact, large capacity, nonlinear and so on [1]. However, current research focuses on building a digital simulation model that bases on the physical mechanism of locomotives mostly, then the characteristic quantities of the system under various operating conditions are simulated and analyzed. Nevertheless, this model is not practical for the simulation calculation of power grid, the equivalent modeling of the composite load of traction power supply system for high-speed railway is relatively few at present.