Algorithm for load-shedding operations in reduced generation periods

The authors develop an algorithm for the selection of load circuits to shed in periods of reduced generation. After reviewing the requirements and operational constraints in load shedding and circuit restoration, the authors develop strategies for the selection of substations and circuits to be shed and restored. These strategies form the basis of the developed algorithm. Formulae for calculating the operating frequency under overload conditions are derived for systems containing motive and nonfrequency-dependent loads. Based on the operating frequency, formulae for the determination of the load shed size are developed and incorporated in the algorithm. The algorithm is declarative in nature and is implemented using Prolog. A logic approach to represent the information and decision parameters of substations and load circuits is outlined. The structure of the developed software system is described and the system is applied to an application example in which the period of reduced generation lasts for 6 h