Transmission Fixed Costs Allocation Using Nucleolus Of Cooperative Game Theory

In the electricity market, the transmission systems are separated from generation systems. As a result, transmission fixed costs that is invested to build a transmission grid should be undertaken by generators and/or users connected to the transmission grid. How to reasonably compute and allocate transmission fixed costs not only is the key of healthy development of power market, but also becomes one of the important problems that must be solved in power market.There are two main allocation methods for transmission fixed costs at present: the embedded cost method and the marginal cost method. The former can guarantee to meet the balance of all costs' income and expense, but it can not provide any economic signals for the users and generators so that it can not induct to make optimal utilization of transmission facilities and long-term development of transmission grid, while the latter whose goal is the maximize of economical benefits of society can make available use of resources of transmission grid, but can not completely recover all the fixed costs. The two methods could not radically solve the allocation problems of transmission fixed costs.This paper proposes to combine the costs allocation problem with game theory, and to assign all transmission fixed costs using a method of cooperative game theory in face of the disadvantages of two methods. In the concepts of cooperative game theory: core is often empty, shaplely exists coalition combination's explosion, nucleolus as a vector of imputation based on core have the characteristic of unique, which can always receive the only value of cost allocation through the nucleolus method in despite of the complicated transmission net. The paper regards the existing transmission systems as a cooperative investment that is formed by all the users based on the investment benefits of scale in the transmission grid, regards the fixed cost allocation problems of transmission systems as the costs allocation problems of cooperative game theory, and mathematics models are setted up using the nucleolus method at the same time, moreover simulations are made with a IEEE 14-bus system. Simulation results show that the costs allocation method based on nucleolus possesses the characteristics of unique and fairness, and can make recovery of all costs, and can also provide available economic signals for the grid users by the comparison of the vectors of profit imputation.