Stochastic Network-Constrained Unit Commitment to Determine Flexible Ramp Reserve for Handling Wind Power and Demand Uncertainties

The flexible ramp reserve of dispatchable generators is a key effective means to compensate the fast fluctuation of wind power generators and the forecast error of demand. This article proposes a stochastic network-constrained unit commitment (NCUC) model to determine, on daily horizon, the optimal schedule of generation units along with the required flexible ramp and spinning reserves under uncertainties of wind power and demand. Point estimate method (PEM) is utilized to reduce the number of scenarios that model wind power and demand uncertainties. In addition to PEM scenarios, some worst-case scenarios based on regional wind and demand variations are defined and incorporated in the proposed model. The NCUC model includes for these scenarios various technical constraints of generation units and operation constraints of the network. To ensure computational tractability of NCUC model, the ac network operation constraints are linearized. The proposed mixed integer linear programming NCUC model is tested using the IEEE 118-bus system. The obtained results show better units scheduling than the conventional (deterministic) NCUC model.