GENERATING-UNIT COMMITMENT IN COMPOSITE GENERATION AND TRANSMISSION-SYSTEMS

A composite generation and transmission system can be divided into var ious states which can be used to indicate the degree to which adequacy and security constraints are satisfied when conducting a system relia bility assessment. In the paper a new risk index designated as the com posite system operating state risk (CSOSR) is defined, using the proba bilities of these operating states. This risk index can be utilised fo r system expansion planning and unit commitment in a composite system. The application of this risk index for unit commitment in a composite system is presented using two test systems. The results for different generating unit lead times for a fixed load level and for variable lo ad levels for a fixed lead time are also presented.