An adaptive load shedding method with time-based design for isolated power systems

When an isolated power system encounters a serious disturbance or a large generator unit trip, the system frequency may drop if total generating power is not able to supply the load demand sufficiently. Since an isolated power system possesses a lower inertia with limited reserves, load shedding becomes a critical solution to restore system frequency. In this paper, the initial rate of change of frequency is first detected. A designated time interval and a modification algorithm that considers the maximum frequency change at the last step are integrated to complete a load shedding task. Features of the method include the easy determination of shedding loads and fast trip of the load in anticipation of avoiding the occurrence of over-shedding or under-shedding. Numerical simulations have solidified the effectiveness of the proposed method for the application. (C) 1999 Elsevier Science Ltd. All rights reserved.