Comprehensive probabilistic assessment on capacity adequacy and flexibility of generation resources

Abstract

The increasing penetration of renewable energy in power systems has been playing an increasingly important role on power system reliability. However, traditional reliability indices of power systems, such as the loss-of-load probability and the expected unserved load, can only reflect the generation capacity adequacy but neglect its flexibility. Focusing on this issue, a set of comprehensive assessment indices that can accurately quantify both generation capacity adequacy and flexibility is proposed in this paper. Specifically, the proposed up-ward capacity shortage probability and expectation indices assess both generation capacity and ramp-up capacity shortages that may cause load loss, while the down-ward capacity shortage probability and expectation assess both base-load cycling capacity and ramp down capacity shortages that may cause renewable energy curtailment. A probabilistic assessment method with the time sequential probabilistic production simulation technology is developed to effectively calculate the proposed indices. This method can adequately consider uncertainty factors, such as the random outages of generating units and forecasting errors of loads and renewable energy, as well as dynamic operation statuses of generating units. Numerical examples are presented to verify the effectiveness of the proposed indices and the evaluation method.