Research On Power System Phasor Estimation

During the power system transients, the voltage and current phasors are the basic electricalquantities to enable almost all protecion relays. Thus, quickly and accurately calculatingpower-frequency phasors during transients is crucial for the power system safe and stableoperation.This project started with reviewing the current methods for phasor measurement. Byanalyzing the signal model used by these methods, the model named “sum of exponentiallydamped sinusiods”was chosen as the study object of this project. Using this signal model,the Fast Extraction(FE) Method based on the idea of Matrix Pencil Methodwas developed.To implement FE mehod, a square matrix was formed by sampling matrices of input signaland reference signal. Its eigenvalues contain the information of the concerned phasors,among which the power-frequency phasor can be obtained. However, the computationburden of eigenvalues calculation is huge. A reduced order method was proposed to simplifythe calculation, transfering the high order matrix into a second order matrix. Simulationresults and theoretical analysis demonstrate that the presented method has low computationalcomplexity and is immune to any kinds of harmonics or attenuated DC components. Inaddtion, this method also has high accuracy even for quite short data window.Based on the FE method, this paper also developed a mehod for frequency estimation calledFast Extraction based Frequency Measurement Method(FE2). This method fully utilizes theadvantages of the Fast Extraction Method and will act as a powerful tool for power systemfrequency estimation.Theoretical analysis, simulation results and comparisons to other hackneyed, traditionalmethods indicate that this proposed phasor estimation method has a superior performance,which makes it a promising approach in engineering practice.