Fourth International Conference On Advances in Computing, Electronics and Electrical Technology - CEET 2015
Author(s) : DILSHAD ARA HOSSAIN, MD MIZANUR RAHMAN, S M SALIM REZA, SAJIB CHAKRABORTY, WAHIDUL HASAN
In this paper, 100% stator ground fault protection by application of low frequency (20 Hz) injection for 6.6/132 KV alternators have been investigated. Here, different types of faults of alternators and possible protections by conventional means have been discussed. It is shown why conventional method by differential relay protection is not adequate. Modern approach of alternator fault protection is reviewed and effective methods of 100% stator ground fault protection of alternators have been applied. In this work, it is focused protection of alternators based on sub-harmonic injection method using low frequency band pass filter. The design of stator ground fault protection consists of 20 Hz signal generator, band pass filter, 20 Hz current relay and protection system model includes alternator, total capacitance to ground of stator winding, grounding transformer turns ratio, and neutral resistor. PSPICE simulation of the protection scheme is performed and analyzed.