Power quality analysis system of electrified railway based on PSASP and virtual node and applications

Power quality analysis calculation is an important power system analysis method, which is always held in high regard by power quality researchers. Electrified railway load destroys the symmetrical operation of the power system that injects harmonic current and negative sequence current into the system. A power quality analysis system based on PSASP is developed in this paper to calculate harmonic current and three-phase voltage unbalance generated by electrified railway. System transformation method and virtual nodes are used in the analysis system to make the two-phase traction power supply system and three-phase power system unified in topology so that three-phase calculation method can be used. The System transformation method, virtual nodes and the structure of PSASP are illustrated. The modification of node admittance matrix and the process of the calculation are discussed in brief. The wscc-9 nodes system example and a practical example show that the power quality analysis system has higher availability.