Research On Medium And Long-term Unit Commitment With Joint Operation Of Wind-Hydro Power

Wind energy is a kind of rich, low-cost, and renewable clean energy reserves. In recent years, with more and more countries recognizing the importance of the development and utilization of wind power, the pace of wind power development is growing rapidly, and the proportion of wind power in the Power Grid is increasing year by year. However, the randomness nature and volatility nature of wind lead to strong unpredictability and volatility of wind power. Integration of large-scale wind power impacts the reliability and security in system operation, which brought new challenges to the system dispatching.The medium and long term unit commitment problem is a very important and complex task when making the medium-term plan of power system. The up or down status and power generation of units should be arranged, considering electric power and quantity require and unit operating constraints. Due to the current level of prediction technique, long-term wind power can’t be predicted accurately. By now there is no medium and long term unit commitment considering the wind power. It will undoubtedly lose the economic and environmental benefits from wind power without considering the wind power. Therefore, the study on making the wind power participate in the medium and long term unit commitment is very important.Hydro and wind power can be complementary in natural and technical, so that adjustable hydro can be used to stabilize fluctuations in the wind power. On this basis, two wind-hydro power joint operation modes is built in this paper, in which wind and hydro power work as a joint system. In the two modes, the capacity is provided by hydro capacity and electricity quantity is provided by both wind and hydro power.On the basis of two wind-hydro power joint operation modes, the paper establishes two medium and long term unit commitment model. On the basis of monthly wind power electric quantity, the first medium and long term unit commitment model with joint operation of wind and hydro power is built. It is on the basis of traditional energy-efficient unit commitment model, with the objective of minimizing the coal consumption of the conventional generator, coordinating the optimal operation of each unit. On the basis of the first model, considering the monthly date statistical properties of wind power, the second medium and long term unit commitment model which considers the average daily output of wind power curve is built in this paper. Simulation results of IEEE20test system show that compared with the model without considering the wind power, the two models mentioned in the paper have lower operating costs and the booting frequency. The capacity of units is also reduced. Compared with the model considering the monthly predictive value of wind power quantity, the model considering the average daily output of wind power curve has better energy conservation. Simulation results above verify the feasibility and effectiveness of the proposed model.