Abstract Research purposes: The number of electrical equipments characterized nonlinear voltage—current is increasingly connected to metro power grids．The harmonics current generated by these nonlinear loads will produce the harmonics voltage on the impedance of metro subway power grids，and will superimpose on the fundamental power system voltage to cause the voltage distortion，resulting in a series of hazards and seriously endangering the traffic safety．In this paper，the discussions are made on the mechanism of harmonic generation and control measures，and the filtering way and harmonic treatment plan are offered for eliminating harmonic current and enhancing power factors．
Research conclusions: Through analyzing the mechanism of harmonic generation and comparing the active filter system with the passive filter system，the harmonic treatment plan with active filter technology is pointed out and the introduction is siren to the working principle，installation principle and option requests of the active filter system．The application of active filter system shows using the active filter technology can effectively eliminate the harmonic current and enhance the power factor of power supply system．
2009, Vol. 26 
