Research On Harmonic Mitigating Based On Double Point Detection Of Single Resistive Active Power Filter In Distribution Sysems

As the application of power electronic devices is becoming increasingly widespread,the harmonic problem is attracting more and more attention.At the same time,due to the rapid progress of power electronic technology,the structural characteristics of the power system lines cause serious threat.It occurs the harmonic voltage amplification on the transmission line,which resulting in local accident and bring a great influence to the power system,and even affect personal safety.Based on the distribution parameter model and the lumped parameter model of the transmission line theory,the phenomenon of background harmonic voltage amplification on two types of distribution network(radial distribution network and closed-loop distribution network)is discussed and analyzed.This paper introduces the midpoint RAPF(Resistive Active Power Filter,RAPF)suppression method and the background harmonic suppression strategy of the double point detection discrete frequency tunning of APF(DPDDFT-APF).Based on this,a strategy based on the double point detection of single resistive active power filter and a new site selection strategy of double point detection discrete frequency tunning of single resistive active power filter are proposed respectively.Finally,the theoretical analysis and simulation and experiment all prove the correctness of the two schemes and the actual operability.The midpoint RAPF strategy uses single RAPF(SRAPF)and installs it at the midpoint,which can achieve the harmonic suppression,but can not realize the harmonic mitigation.In order to solve this problem,a new method based on double point detection of SRAPF is proposed.It detects the harmonic voltage of two nodes(one node is the midpoint and the another is one node excepted the midpoint)and only one RAPF is installed at the midpoint of the line.By adding a detection point,the strategy not only has the function of the midpoint RAPF control scheme,but also can effectively mitigate harmonic.At the same time,it has better robustness and harmonic mitigation effect under the line impedance changing condition.In this paper,a new location selection scheme of the double point detection discretefrequency tunning of SRAPF is proposed,which is based on the double point detection discrete frequency tunning of APF in radial distribution network.Based on this,the installation point and the detection point position of the SRAPF are respectively proved theoretically,which is chosen to suppress the resonance propagation of the background harmonic voltage in the power system and realize the effective mitigation of the harmonic voltage.The experiment platform is built with TMS320F2812 DSP to verify the correctness of theoretical derivation and simulation analysis.