Unit Commitment for Systems with High Penetration of Wind Power

High uncertainties in day-ahead unit commitment (UC) introduced by the deviation of wind power forecast error require high amount of spinning reserve, which counteracts the cost and fossil energy saving contributed by wind power integration. To mitigate the above problem, a two-level unit commitment coordinated strategy (TLUCCS) is presented based on the characteristic of wind power forecast accuracy that can be improved gradually as forecast horizon shortens. In the TLUCCS, the traditional UC strategy is expanded to two coordinated UC levels, which are primary (day-ahead) UC (PUC), and secondary UC (SUC) with the time scale of a few hours in advance. The spinning reserve in PUC is decreased so that the operating costs can be reduced. To guarantee the system reliability, the SUC will be carried out when the spinning reserve capacity cannot meet the actual demand in intraday operation, which may result in additional start-up costs. To obtain the most economic UC scheme, the optimal spinning reserve demand in PUC should be determined, which is quantified with a time sequence simulation simulation method in this paper. Case studies validate the proposed strategy and the method.