SPINNING RESERVE ASSESSMENT IN INTERCONNECTED GENERATION SYSTEMS

Most utilities use deterministic techniques to evaluate unit commitment and spinning reserve requirements. Deterministic approaches do not specifically take into account the stochastic behaviour of system components in the determination of spinning reserve requirements. A probabilistic technique designated as the 'Two Risks Concept' which considers the stochastic behaviour of system components as an integral element has been developed to assess spinning reserve requirements in interconnected systems . The technique provides a rational basis for spinning reserve allocation amongst each individual system within an interconnected configuration. The technique and its fundamental features are illustrated in this thesis. The effect on the required spinning reserve of related system parameters, generating unit failure probabilities and tie-line capacity are also illustrated. The technique incorporates the essential factors in interconnected systems which directly or indirectly influence system spinning reserve requirements. The spinning reserve requirements in an interconnected configuration involve the recognition of contracted agreements such as export/import conditions between systems. The development of export/import models and a corresponding spinning reserve assessment process are presented in this thesis. The availability of rapid start and hot reserve units and interruptible loads can reduce the unit commitment risk for a given set of generation and load conditions. Rapid start and hot reserve units have been included in the time dependent risk calculation using the Area Risk Technique. The effect of load interruption on required spinning reserve has been studied in detail. A technique to determine the maximum allowable time delay for load interruption is reported in this thesis. A generating system can carry an additional load/interruptible load on top of its firm load due to the discrete size of the generating units without having to commit any additional units than those required to carry the firm load. A technique to determine the additional load/interruptible load carrying capability of isolated and interconnected systems is presented in this thesis. A unit commitment technique for continually changing loads in interconnected systems has been developed based on the 'Two Risks Concept'. The unit commitment during a specified scheduling period is constrained by risk criteria and economic factors. The unit commitment technique in the presence of contracted export/import and load forecast uncertainty is described in this thesis. A risk constrained unit loading technique for interconnected systems is also been presented in this thesis which utilises a least costly deviation from economic load dispatch to satisfy the risk criteria. Two reliability test systems have been utilised to conduct studies based on the 'Two Risks Concept' and the results are presented in this thesis