A new load shedding scheme for limiting underfrequency

In large interconnected power systems, serious frequency falls now require a very heavy loss of generation and should such an event occur, the rate of frequency decline would be greater than had been considered at the time when underfrequency load shedding (ULFS) had been developed. Obviously the character of the power systems have changed and yet no corresponding modification of ULFS has been made and there is still shedding of pre-selected loads throughout the entire power system. This paper proposes a new scheme utilising frequency and voltage changes to shed loads specifically in the most affected localities while regaining the load-generation balance for each incident. Simulation studies on an extensive interconnected network, following very severe loss of generation, show the advantages of the proposed scheme to the actions of existing ULFS