Analysis of the negative sequence interactive impact of traction power supply system on the urban power grid

Abstract

The high-speed railway adopts single-phase power supply, which is asymmetric load for the three-phase power grid. Its high power and fluctuation characteristics will cause the negative sequence voltage problem of urban power grid. With the rapid development of high-speed railway in recent years, this problem is becoming more and more serious. Therefore, it is urgent to analyse the negative sequence of the urban power grid caused by TPSS (Traction Power Supply System). Usually, the mathematical and simulation model of TPSS is established to analyse the power quality of TPSS. However, the modelling process is usually simplified, and the load of TPSS has randomness and volatility, which makes the simulation results deviate from the actual results. Therefore, based on the measured data of TPSS loads and the method of dynamic power flow calculation, considering the factors of station number, common phase of traction transformer and train marshal, the negative sequence influence of TPSS on the whole urban power grid under different conditions is analysed in this paper. Finally, the feasibility of alternation commutation phase to weaken negative sequence voltage is verified.