A New Adaptive Underfrequency Load Shedding Scheme to Improve Frequency Stability in Electric Power System

This paper proposes a new adaptive underfrequency load shedding scheme (UFLS) to avoid frequency instability in electrical power system during abnormal wide area disturbances. The developed is based on online monitoring of the distance relay zone 3 decisions some tie lines using (WAMS) and SCADA/EMS systems, check rapidly reliably uncontrolled islanding conditions and, permit an automatic action maintain stability system. Simulation results 400 kV Turkish transmission systems demonstrated effectiveness proposed compared current schemes which they cannot consider all possible circumstances because their limited access network data. clearly indicate that large disturbances can be avoided propagation also stopped scheme.