A method of tracking voltage flicker envelope real-time

Fast and accurate tracking of voltage flicker envelope is significant to the performance of flicker meter, flicker source location and the mitigation of voltage flicker. Using the energy of a signal and its shifted signals to track the envelope of voltage flicker is presented in this paper. It is assumed that the signal is shifted, once by a lead angle equal to beta, and at another time by a lag angle equal to beta, which generates two new signals u⁺(t) and u^-(t). According to the energy differences, the relationship between the flicker amplitude and u(t), u⁺(t), u^-(t) can be obtained, so the voltage flicker envelope is successfully tracked. How to obtain the shifted signals u⁺(t), u^-(t) is analyzed in the paper. The frequency error e_f(%), amplitude error e_m(%) and waveform standard deviation sigma(%) are used as the weighing index of the accuracy of tracking flicker envelope. The theoretical analyzing and RTDS simulation test verify that the suggested method is accurate, fast and anti-noise.