Unscheduled interchange (UI) price based secondary frequency control of an interconnected hybrid power system

The availability based tariff (ABT) structure introduced by Government of India established inter region grid discipline through Central Electricity Regulatory Commission Regulation 2009. Using this regulation the over /under injection by the generators during off-peak/peak hours are discouraged and the frequency is maintained within a range amongst five regional grids of India. This work follows the rules of frequency regulation based on unscheduled interchange (UI) charges for power flow between three interconnected area having different combinations of thermal, hydro and diesel power generators. This UI based secondary frequency control scheme is simulated in MATLAB/Simulink. Though the system response is slow, but it finally establish the frequency within the specified limits (50.3 Hz - 49.2 Hz) and economic power generation is maintained.