Detection And Suppression Of Voltage Fluctuation And Flicker

The voltage fluctuation and flicker is an important aspect of power quality problems,is mainly caused by the impact resistance, non-linear load in power supply system.Voltage fluctuation will affect the normal operation of the sensitive load, and in severe endanger the safety of equipment or causing huge economic losses, also cause the lighting flashes that make people’s visual discomfort and fatigue,even bring about irritable mood because of unbearable, thereby reducing the work efficiency and quality of life.As an important indicator to assess power quality, flicker can reflect the quality of the power grid more directly and more quickly.There are two important parts of voltage fluctuation and flicker detection, one is to extract the voltage fluctuation signal envelope and analysis the extracted envelope effectively, the other is to determine the short-term flicker severity Pst. This paper has done some theoretical analysis and research to voltage flicker detection methods, analysised the respective strengths and weaknesses of several commonly used detection methods by simulation.Then simulated the flicker detection method recommended by IEC of analog and digital systems in Matlab/Simulink environment. Through the occurrence of fluctuation signal and the detection result of voltage fluctuation,we can see the system realized detecting and filtering the voltage fluctuation, proved the correctness of the analog and digital simulation system. The main computation indicators of flicker meter short-term flicker value Pst,this paper calculated Pst by the statistics sort method, the relative error of the calculated results met the calibration standards of IEC flicker meter.Grid voltage fluctuation and flicker is mainly caused by the fluctuation and impact of reactive power, the fluctuation of active power affects the grid voltage smaller, so the suppression of voltage fluctuation and flicker should focus on to control parallel reactive power compensation.For this reason,this thesis researched the principle to control voltage fluctuation and flicker of commonly used reactive power compensation device, analysised theie function and characteristics in the suppression of ilicker,and established STATCOM and UPQC simulation model to inhibit voltage flicker, verified the effectiveness of the suppression method.