A Novel Power Quality Comprehensive Compensator Device Research In Distribution Network

Power plays an important role in the economic development of modern society and the improvement of people’s living standard.Meanwhile,it is also the progressive symbol of the development of a national industry, the enhancement of technical level and social civilization. In recent years,a great deal of new power electronic equipment are used in the power system.It causes the voltage fluctuations, flicker and three phase imbalance in power system, which brings out serious pollution to the quality of power supply, affecting the safe operation of electrical equipment.This paper aims to study a new type comprehensive power quality device to suppress the harmonic.It combines the function of voltage quality control(VQC) device and active power filter (APF).It both can realize the voltage quality control, and can realize the governance of harmonic current governance . It can greatly improve the quality of power grid, reduce line losses.Besides,it can also realize dynamic regulation of harmonic impedance,to avoid the local resonant in power grid.This paper introduces power quality problems and present status appearred in the power grid. It makes a deep study on the typical load in the power quality problems.It analyzes the problems of harmonics and reactive power in different condition.This paper introduces the detection and control methods of reference signal in the power quality problem and the development of power quality control device.Based on the deep study of the shortcomings of traditional voltage and reactive power control devices,this paper proposes a comprehensive Harmonic Suppress and Voltage Quality Control(HSVQC) power quality device to suppress the harmonic.It can not only compensate the reactive power,but also suppress the harmonic dynamically.By the study of topology and operating principle of the proposed device, the paper proposes several new structures. The simulation results verify the validity and stability of the device.It proposed a separate frequency detection arithmetic with forecast estimate and a double hysteresis space vecter control method.firstly,they are start form detection and control of power quality parameters in distribution network and then the voltage,reactive power and harmonic current detection methods based on the reactive power and harmonic current detection method in instantaneous power theory are introduced separately.finally,Voltage and reactive power control method which is based on fuzzy reactive power boundary theory is used to derivate them.With multiple target optimization of voltage,reactive power and harmonic current,the performance of equipment becomes better and the output of compensation reduced to minimum.At last,on the basis of optimization design of the system main circuit parameters which mainly contains researches on reactive power equipment、series resonance branch and optimization of main circuit parameters in inverter,along with the software and hardware design scheme of controller upper and lower computer,the paper verified actual effect integrated with actual operate condition simulation and debugging of model machine in a substation.The equipment not only guaranteed the level of voltage stabilization and improved the system stability,it as well brings about significant economic benefits and social benefits because of the improvement of power factor and the decrease of voltage aberration rate and line loss.