The Detection And Control Of Dynamic Power Quality

Power quality issue is increasingly prominent due to the composition changes of power systems load and the further progress of the electricity market. Dynamic power quality phenomenon, such as voltage sag, discontinuity, has made attention to people and became a focus of power quality analysis, owning to the frequency occurrence of randomness and serious harm to sensitive equipments. Therefore, taking reasonable measures to improve power quality, it is desirable to detect and control dynamic power quality.The magnitude and duration time of perturbation voltage are primary characteristics of dynamic power quality problem. During the analysis of dynamic power quality problem, it is very important to remove noise, locate perturbation time and classify perturbation. In this paper, wavelet and wave packet method, artificial intelligence technology and DQ translating method based on instantaneous reactive power are introduced and summarized about their advantages, disadvantages and application. A new method of dynamic power quality problem detection is propose based on the most staple and simple DQ translating method combining with Order morphological transform. Firstly, this method carries out double DQ translating and no time-lapse single-phase DQ translating, then via low-pass filter, the positive, negative and zero voltage sequence can be obtained. Finally the magnitude and duration time jumping angle of perturbation voltage can be deduced. It can meet the real time requirement to detect dynamic power quality problem by D-FACTS equipments.Dynamic Voltage Regulator(DVR)is regarded as the most important equipment of D-FACTS by its favorable performance and efficiency to control dynamic power quality problem. The main circuit of DVR is discussed in this paper, and voltage compensate method, voltage control tactic are studied. Afterward, build a system simulation model and proposed a new voltage detection method including order morphological filter and PID control mode. The simulation results verified the detection and control tactics are reasonable by its feasibility and validity.