Research On Selection Method Of Transmission Congestion Management Mechanism

At present,the reform of power system in China has developed rapidly,and the power spot markets are already in preparation in many provinces(regions).After the spot market establishing,the management method of the transmission congestion will be changed essentially.The problem of the transmission congestion management under the electricity spot market is one of the important issues that need to be solved.Each of the transmission congestion management mechanisms has its specific scope of application.However,the selection methods and applicability analysis of the transmission congestion management mechanism in the existing research mostly stay at the qualitative analysis.A general set of quantitative evaluation indicators for the transmission congestion management mechanism that provide a reference for selecting an appropriate transmission congestion management mechanism for the emerging power market has not been proposed.Based on the simulation of the electricity spot market,this paper proposes a s set of quantitative evaluation indexes and a comprehensive evaluation method to evaluate the applicability of the transmission congestion management mechanism.The specific research contents are as follows:Firstly,the management mechanism of the transmission congestion applied in the foreign power market is reviewed.The selection of the transmission congestion management mechanism is closely related to the power market model and price mechanism.This paper summarizes the four congestion management mechanisms that are the re-scheduling method,the market splitting method,the nodal price method and the transaction reduction method.And the qualitative analysis of their applicability to is conducted.Secondly,a set of quantitative evaluation indicators for evaluating the management mechanism of transmission congestion was established,and a quantitative analysis method based on the simulation calculation of electricity spot market and the applicability of comprehensive evaluation of transmission congestion management mechanism was proposed.The applicability of the transmission congestion management mechanism should be based on market efficiency.Market efficiency can be measured by the social welfare considering transaction costs and power generation external costs.In the case that it is impossible to quantitatively evaluate the external cost of power generation,considering that market power may affect market prices,congestion costs increase the cost of consumers,and the proportion of renewable energy consumption reflects the efficiency of resource optimization allocation to a certain extent.Therefore,this paper takes social welfare,market power,congestion costs and renewable energy consumption ratio as the first-level evaluation indicators to evaluate the applicability of the transmission congestion management mechanism.After calculating the various indicators according to the unit cost-based production cost simulation method and normalizing them,the weight coefficient of each index is determined by the analytic hierarchy process,and then the comprehensive evaluation of different transmission congestion management mechanisms is studied for selecting suitable transmission congestion management mechanism.Thirdly,the example of the selection method of the transmission congestion management mechanism proposed in this paper is verified.It simulates the process of applying different transmission congestion management mechanisms to eliminate congestion in the future electricity spot market.The results of the example show that under the same scenario,the comprehensive evaluation indexes of different transmission congestion management mechanisms are different,especially when there are many congestion lines in the system,which demonstrates the effectiveness of the proposed indicators.At the same time,the difference of load characteristics will also affect the choice of mechanism.It is impossible to select the transmission congestion management mechanism by simple qualitative analysis method.Therefore,the quantitative analysis method proposed in this paper is of great significance.