Power System Protection Using Tf-analysis and Pattern Recognition

Unlike the conventional relaying schemes, using fuzzy systems and neural networks, the proposed research work presents a novel technique for distance and differential protection, using time- frequency analysis and pattern recognition approach. The time-frequency transform such as S-Transform and its variations are used for fault detection, classification and location determination for transmission lines. The S-Transform is an extension of Wavelet Transform which possesses superior property over the latter as the moving functions are fixed with respect to time axis while the localizing scalable Gaussian window dilates and translates. decreasing with frequency providing a frequency dependent resolution. S-Transform is used for finding out the amplitude and phase, which are used for impedance calculation to the fault point. Also energy and standard deviation of the S-matrix are computed to detect and classify the fault patterns. Intelligent techniques such as Support Vector Machine (SVM) are embedded to the proposed protection schemes for automatic recognition of the fault patterns for transmission line including FACTS.