Stability of system is one of the main considerations of power system. Voltage, Angle and Frequency instability are the basic instability problems. The instability which mostly causes severe damage like blackouts is nothing but frequency instability. This instability is either due to generation-load unbalance or N-1 contingency. History has seen several blackouts due to frequency instability. In past years electromechanical, solid state frequency relays were analyzed. Also the concept of digital frequency relay was introduced. But after distributed generation and the possible is landing...