Research On Power Quality Disturbance Identification And Recognition

With the proliferation of electronically controlled equipments in power system, power quality has been a great issue to both suppliers and users of electricity. In order to improve the power efficiency, it is necessary to detect the power quality sensitively, classify them accurately and clear them effectively.A method which uses instantaneous reactive power theory and wavelet transform is put forward in this paper. It can detect and classify the familiar power quality disturbances effectively. Firstly, the beginning and end time can be detected by the power quality signals transformed using instantaneous reactive power theory , then classify the other signals using the sensitivity of wavelet transform to sudden-change signals and features of frequency by wavelet transform, The efficient and validity of this method is verified by the calculation results.A method to identify the frequency and magnitude of the flicker is proposed in this paper too. The virtual three-phase voltages can be obtained by delaying the signal, and the three-phase currents can be substituted by the three-phase voltages. Using instantaneous reactive power theory, the instantaneous active power and the flicker envelope are obtained. Then discuss the flicker envelope using FFT algorithm with high accuracy , the frequency and magnitude of the flicker can obtained. Feasibility of the method to estimate parameter of the voltage flicker is evaluated by illustration of the simulation examples.