A Study On Peak-shaving Procedure And Its Application To Multiple Hydroplants

With the development of society in China, rapid increase of peak load, great gap between peak load and valley load and the low load rate can be seen in many power grids in the recent years. Thus there is a lot of pressure in peak-load regulation. In addition, the absorption of the wind power also have the demand of peaking capacity. Many large scale hydropower systems like the cascade stations and inter-basin hydropower stations group have emerged due to the vigorous development of the hydropower facilities in our country. Hydropower is a kind of high quality peaking power. It is necessary and of great value to make the long term peaking operation to give full play to the compensation benefit of cascade stations and the joint basin stations for the reliability and the economic operation of power grid.The long-term optimal operation of the hydropower stations is always for the porpose of improving the benefit of the power generation and have less research results compared with the short-term peaking operation. But the long term operation plan has a great influence on the short-term, it is hard to reach the expected benefits and even destroy the stable operation of power grid regardless of the long-term peaking demand. Therefore, this paper studied the long term peaking operation of the inter-basin stations and the main content is summarized as follows:First, the paper carried on the detailed analysis of the characteristics in peak load regulations of hydropower stations, it expounded the advantage of the combined operation and the importance of both short-term and long-term coordination model. The premise and foundation of making the peaking operation model is establishing the realization of the peaking task. Hence it classify and analyze the existing peaking model from this perspective.Secondly, on the basis of above study,it takes the load rate of the power grid into consideration. Load rate represents the stablity of the load. It is critical to improve the load rate for the power grid and thermal power.So this paper establishs the long-term peaking load rate model for the hydropower stations, the model's objective function is to maximum the minimum of the load rates of the residual load curve of periods' s typical days in the long term. Typical day power scheduling is very improtant in solving the model. This paper uses the successive load shedding algorithm to handle it. Besides, it analyses the feasibility of the POA algorithm in solving the maxmin problem and uses the POA method to solve the load rate model.Finally, the paper applies the load rate model into the Hunan Power Grid for the cascade stations in Yuan Shui river and all the inter-basin stations of the four rivers.The case study shows that the proposed model is effective and the hydropower stations mainly take all the peak load and some of the mediate load during the year and the residual load curve for the thermal power is flat. It also compared the proposed model with the long-term maximum power generation model and the long term typical day peak load regulation energy maximization model, the result shows the advantage of the proposed model in this case.