A new hybrid digital technique for differential protection of salient pole synchronous generator

In this paper, the development and implementation of d-q axis components and wavelet packet transform (WPT) based hybrid technique for digital differential protection of a salient pole synchronous generator is presented. The analysis is concentrated on the high frequency sub-band contents of WPT obtained from the d-q components of the differential currents of the relay. It has been found that the analysis in this approach provides enough information to detect any fault in the synchronous generator. This hybrid technique provides good accuracy and fast fault clearance with only one level of WPT of the d-q axis components of the current. Off-Line testing is carried out for the data collected from an experimental work on a laboratory salient pole synchronous generator for different types of disturbances. Moreover, the algorithm is verified by Real-Time experimental tests on the laboratory salient pole synchronous generator.