New algorithm based on auto-correlation and cross-correlation scheme to detect the internal fault in single phase transformer

A new algorithm based on the correlation analysis of waveforms to detect an internal fault occurs in a single phase transformer is proposed. The algorithm depends on the changes in differential current waveform that occur during internal fault. Auto-correlation added to cross-correlation algorithm for enhancing the security and speed in detecting the fault within the first half cycle of internal fault waveform. The scheme has been tested by using Matlab/Simulink software. The test results show that the internal fault even inter-turn type can be correctly identified from external fault. The algorithm is simple and can be implemented in real-time process.