Capacity Credit Evaluation Of Wind Power Considering Coordinated Operation

Wind power has developed rapidly in China in recent years with its firm increase in proportion of the total power capacity. However, wind resource has a very concentrated distribution in our country. Large scale wind power base is being built far away from the load center, which makes the planning of power system more challenging. The problem is how to scientifically estimate the capacity credit of wind power when it is delivered by long distance and bundled with other power source.From the perspective of power system reliability, planning wind power need to consider two questions:one is that how much capacity of wind power construction can replace a certain capacity of conventional generation when load remains constant; the other is how much wind power capacity must be added to ensure the whole adequacy of the system when load has a certain growth. Wind power capacity credit evaluation is of great importance to the above question.Firstly, in order to improve the speed of computing wind power capacity credit, a simplified method of wind power output model is proposed in this paper. According to the probability distribution of wind speed, the two state model of wind power output is calculated by differential method. The available capacity of all the generations is then calcaulated by adding the two state wind model. This method greatly improve the efficiency of adequacy evaluation by shortening iteration calculating time. The influence on wind power capacity credit of wind power installed capacity and local wind condition are investigated by applying this method.The calculation of wind power capacity credit needs multiple times of system adequacy evaluation. So the calculation speed is always a problem. In this paper, a simplified wind power output model is proposed. According to the probability distribution of wind speed, using differential method to calculate the two state model of wind power output. Then, the capacity outage probability table is applied to evaluating system adequacy which make the computing speed improved greatly.Then, The key point to calculate the capacity credit of wind power is to estimate the system adequacy including wind power. But at present most of the studies only focus on power generation systems, ignoring the influence of transmission line topology and its capacity limitation. Therefore, a sequential monte carlo method is applied to evaluate the system adequacy containing transmission line. Wind power capacity credit is calculated and compared under different connection scheme.At last, Sequential monte carlo method is applied to study the capacity credit of wind power using ELCC as evaluation index when wind power is coordinated with hydro power. A formula to calculate the capacity credit under coordination conditions is proposed. The varying pattern of capacity credit is pointed out for different scenes of wind power penetration and water inflow. The amount of adopted wind energy and fluctuation of wind power is discussed under different coordinated strategy.