A Weekly Scheduling Method for Hydro and Thermal Unit Commitment

Abstract

In a transmission network open access environment, an efficient comprehensive generation scheduling taking into account the transmission network will be required. This paper proposes a practical hydro-thermal unit commitment scheduling considering the transmission network.
The proposed technique consists of a multi-stage screening algorithm for processing the operation constraints and a feasible solution is obtained using a heuristic multi-stage approach. At first stage, we decide an initial schedule by relaxing various operation constrains of the thermal units and reservoir storage constrains of hydro power stations. Second stage processes the thermal unit operation constrains of the spinning reserve and minimum up and down time taking into account the hydro system operation. At final stage, we screen the violation of reservoir storage of hydraulically coupled power stations. In each stage, calculation of transmission losses using an optimal DC power flow is carried out and it is expected to realize a more detailed and realistic schedule than the conventional one in which transmission losses are ignored. The application results for a 53 buses model power system including 12 thermal units and 24 hydro power stations of 7 rivers show the effectiveness of the proposed method.