Research On Harmonic Propagation Suppression Based On Double-RAPF In Distribution Systems

As an indispensable energy resource of modern society, electrical energy has beenapplied extensively in different areas, promoting the rapid development of the society. Theharmonic propagation phenomenon in distribution systems, which connect the load centreand the user, not only influences the normal operation of the equipment seriously, but alsogreatly threatens the human safety.According to the two main background harmonic sources including harmonic voltagepenetrating from the higher level system and harmonic current injected by non-linearloads in distribution systems, this paper builds the distributed-parameter model andlumped-parameter model respectively based on the transmission line theory. Thedistributed-parameter model is employed to analyze the causes of the harmonicproliferation or amplification, while the lumped-parameter model is used for simulationand experiment validation of theoretical analysis.To overcome the shortcoming that installing a shunt resistive active powerfilter(RAPF) at the end of the transmission line can only damp out the backgroundharmonic magnification effectively instead of attenuating the existing harmonic further,this paper proposes a double-RAPF strategy.The proposed strategy installs an additionalRAPF2on the location which is a quarter of the dominant harmonic wavelength awayfrom the beginning of the transmission line, while RAPF1remains on the end bus. Theconductance gain of RAPF2is not required to match the characteristic impedance, andlarger gain leads to better damping performance. In addition, the reason whydouble-RAPF can suppress the harmonic on the transmission line further is clarified byboth theoretical analysis based on distributed-parameter model and simulation based onlumped-parameter model.An APF experiment platform with TMS320F2812and9km radial transmission linebased on the lumped-parameter model are chosen to verify the feasibility of the proposedDouble-RAPF strategy. Experiment results suggest that Double-RAPF can suppressharmonic propagation more effectively than trational RAPF.