A Novel Flexibility Evaluating Approach for Power System Planning under Deregulated Environment

Traditional production cost simulation has not taken consideration of the influences of electricity market and the bidding strategies of generation companies. Thus, if it is used in a deregulated environment, the result would be far away from what it should be. Furthermore, it would probably cause risks to system operation in the future deregulated environment. Based on this analysis, we can come to a conclusion that the evaluating process must be updated according to electricity market simulation. A simplified market simulation method for power system planning is proposed. This method focuses on market simulating, including the trading process and the bidding strategy of the generation companies. It is a simplified method of electricity market operation simulation which is called "electricity market simulation used in power system planning". It holds the key point of the trade by combining the regulated planning and the electricity market. By using the simplified market simulation method, this paper presents a flexibility evaluating framework for power system planning under competitive market. This framework tries to take various factors involved in power system planning and electricity market into consideration as a whole. It emphasizes the mutual impacts of the generating units, power grid, system load and trading. This framework adopts the method of comparison of multiple schemes to evaluate the flexibility. It can be separated into several steps as following: the flexibility evaluation between generating units and power grid, the flexibility of generating units to system load, the flexibility of power grid to system load, the flexibility of generating units to bidding strategies, the flexibility of power grid to bidding strategies and the flexibility evaluation between system load and bidding strategies. Because of the large number of variation of bidding strategies, this framework adopts scenario analysis method to evaluate the scenes with larger probability or essentiality. According to the rules of East China regional electricity market, the proposed method has been put into application in the evaluation of power system planning in Jiangsu Province, and some valuable results are given which has been approved by relevant department.