Analysis of harmonic current characteristics injected into unility grid by urean rail transit

Abstract

Non-liner electrical devices are heavily used in urban rail transportation, which is a typical case of the trend of power-electronics on the power demand side of new energy-dominant power system. Analysis of harmonic current injection caused by urban rail transportation is of great significance to the safety and stability of the power grid as well as power quality. Based on actual test data of a certain urban rail transportation, the electric power consumption throughout a whole day is analysed; harmonic current content as well as 95% probability of the 2nd to 25th harmonic currents is calculated; assessment with reference to the national standard limits is carried out; the correlation between dominant harmonic current and fundamental apparent power through curve fitting is revealed. Then, harmonic current content and potential risk caused by the no-load closing magnetizing inrush current are investigated. Finally, the key research issues on technology supervision and management of urban rail transportation harmonic current injection are discussed. The work of this paper may be a technical reference for the planning, operation, and harmonic current prevention of the increasing rail transportation in the new energy-dominant power system.