Algorithm for power swing protection using DSP based numerical relay

The major disturbance occurred in the Northern grid of India on 30
^th
July of 2012 causes shutdown of power in eight state. The main cause was the mal functioning of distance relay due to power swing, weak inter-regional corridor and multiple outage of line. To avoid this situation a modified algorithm is proposed for numerical relay embedded with digital signal processor (TMS320F2812) to protect grid during power swing and avoid the unforeseen blackout. The new algorithm is simulated for numerical relay and gives the expected result and prevents the leading of blackout in electricity grid. This paper describes the algorithm for mho relay to protect the transmission line from power swing disturbance. In electrical power transmission network detection of power swing is very useful for transmission line protection; using this variable signal the protective system can be improved. In this work the power swing is developed by two ways, first one is due to loss of generation and another is due to three phase fault. Modern protective relays based on digital signal processor are capable to perform fast calculation and improve the protective scheme of transmission line.