Time-Frequency Analysis of Power Distortion under Fault Conditions for Grid Connected Wind Turbine

This paper serves the idea of designing appropriate method for complex investigations of transient states in wind power plants. Proposed algorithms belong to two-dimensional time-frequency representations. Additional dimension allows to obtain simultaneous information about frequency of distortion components as well as its duration time. Two algorithms were proposed: short-time Fourier transform (STFT) and Choi-Williams Distribution (CWD). In order to explore advantages and disadvantages of the method in application for wind power plants area, several experiments were performed using model of squirrel-cage induction machine connected directly to the grid. Investigated phenomena concerned power distortion caused by different kind of faults as well as influence of wind speed on instantaneous character of the transient states.