Flexible Transmission System Expansion Considering Accommodation Capacity Of Large Scale Wind Power

With the gradual development and construction of 7 giga-watt wind power bases in China, the accommodation problem of large scale cluster wind power has brought significance to the stable operation of power systems. The initial planning of these bases was determined according to evaluated wind resources and construction condition without analysis of the operation characteristic of power system. Therefore, based on the determined wind power planning, during the later stage, transmission system planning and operational dispatch will be the key facor of whether wind power could be well accommodated. Considering the characteristic of randomness, fluctuation and intermittence, as well as the influence that wind power would bring to peak/frequency regulation, system reserve and operation mode of other units, the traditional method has not a good solution to the problem of transmission system planning with large scale wind power integrated. Hence, the definition of planning objectives under this background as well as the new planning principles, models and tools will be a worthy project for research.The impact of large scale wind power integration to peak regulation, unit commitmenet and transmission expansion is firstly analyzed. On this basis, several indicators are proposed to evaluate the wind power accommodation capacity, which is the accessible capacity of wind power, economic cost and system risk.Based on the mentioned definition, models and algorithms of flexible transmission system planning are proposed. Models of this paper can be categorized to 3 parts. First is the optimal unit commitment problem from the aspect of of power sytem dispatch. Second is the pure transmission system expansion problem considering wind power accommodation capacity. The third part proposed a joint optimization based on the coupled relation between unit commitment and transmission expansion. Finally, fuzzy multi-objetive method is used to unify all the evaluation indicators of wind power accommodation capacity and thus the planning schemes can be well chosen by the fuzzy satisfaction indicator.