Optimal electromagnetic hybrid negative current compensation method for high-speed railway power supply system

Abstract

To achieve economical compensation for the huge-capacity negative sequence currents generated by high-speed railway load, an electromagnetic hybrid compensation system (EHCS) and control strategy is proposed. The EHCS is made up of a small-capacity railway static power conditioner (RPC) and a large-capacity magnetic static var compensator (MSVC). Compared with traditional compensation methods, the EHCS makes full use of the SVC's advantages of economy and reliability and of RPC's advantages of technical capability and flexibility. Based on the idea of injecting a negative sequence, the compensation principle of the EHCS is analyzed in detail. Then the minimum installation capacity of an EHCS is theoretically deduced. Furthermore, a constraint optimization compensation strategy that meets national standards, which reduces compensation capacity further, is proposed. An experimental platform based on a digital signal processor (DSP) and a programmable logic controller (PLC) is built to verify the analysis. Simulated and experimental results are given to demonstrate the effectiveness and feasibility of the proposed method.

Loss Minimization of Electrified Railway Traction Systems Using SVC Based on Particle Swarm Optimization

“…A N electric locomotive in a railway traction system is a great source of negative sequence current, harmonic currents, and voltage level reduction because it can be represented by a line-to-line load with an unbalanced characteristic [1]. Therefore, exploiting static var compensators (SVCs) has been considered a promising method to mitigate problems regarding power quality in railway traction systems [2]- [6]. In [2]- [3], a constant AC voltage control function was investigated for a railway traction system.…”

“…In [4], the feasibility of an SVC was investigated at different positions. In addition, compensation methods for a negative sequence current in a three-phase system were developed in [5] and [6]. However, while SVC is being exploited for various purposes in the conventional power network (i.e., system loss minimization, profit maximization, and operating cost minimization), studies on the operation of SVCs in railway traction networks are scarce.…”