Studies On Game Models And Algorithms For Electricity Market Under Different Transaction Modes

The market-oriented reform of the world's power industry is gradually becoming the mainstream.The goal of the reform is to break the monopoly of the power industry and gradually introduce competition in the generation and sale sides,which improves the production efficiency of the entire power industry.However,to a large extent,the power industry still presents a landscape of oligopoly and its market-oriented reforms are subject to many restrictions.Because of the particularity of the power industry,effective tools are necessary for market participants to provide decision-making basis in order to obtain more market returns.Whether it is a foreign electricity market that is in operation or a domestic electricity market that is in a transitional period,how to help market participants make decisions based on different transaction modes with the goal of improving the production efficiency of the power industry,which is an important theoretical and practical issue that both academic and industrial circles are concerned about.Based on bilateral transaction mode,bilateral transaction mode with price cap and tradable green certificate mode,this thesis studies noncooperative game model and leader-follower game model and their algorithms for electricity market.The main contents are summarized as follows:Bilateral transaction mode is a transaction way that reflects the marketization of electricity market and the free choices of both parties.By withdrawing the price fixing mechanism for the power grid,the bilateral transaction mode is helpful in transforming the power grid's profit pattern,liberalizing the generation side and the sale side,eliminating the transaction monopoly and encouraging competition among generators.As the interaction among transaction agents in the electricity market becomes more complex,the study of bilateral transaction mode requires richer and more flexible modeling methods.Under the bilateral transaction mode,with the goal of maximizing the profit of generators,this thesis constructs a noncooperative game model among multiple power generators.By means of Karush-Kuhn-Tucker conditions,this thesis reformulates the Nash equilibrium problem into a nonsmooth mixed complementary problem,proposes a modified Jacobian smoothing method based on smoothing technique,and proves the convergence and convergence rate of the method.Numerical experiments further verify that the proposed method is able to find the Nash equilibrium of the game model under the bilateral transaction mode.The results indicate that increasing the number of generators and encouraging competition on the generation side are conducive to the reform of the electricity market.Under the bilateral transaction mode,big users own more options and choose strategies to achieve flexible transaction modes so that transaction risk is reduced.The government is suggested to expand the number of generation companies and introduce a competitive mechanism so that a more open market environment is created.Under the mode of bilateral transaction,due to the obvious changes for the demand of electricity in the market,the price of electricity is fluctuating.In order to prevent the electricity price from being too high,in some cases,the government requires that the electricity price should not exceed an upper bound,i.e.,price cap.The existence of the price cap leads to horizontal segment of the price function at the initial stage,which leads to the nonsmoothdess of the price function.Mathematical models with linear price function or other smooth price function are no longer applicable to the price cap situation,unless the price never reaches the required upper bound.This thesis studies the noncooperative game model among power generators under the situation of the price cap.The Nash equilibrium problem is converted into a nonsmooth second-order cone complementarity problem by the Karush-Kuhn-Tucker conditions.Compared with the nonsmooth mixed complementarity problems,the nonsmooth second-order cone complementarity problems are more general.This thesis makes use of smoothing technique and proposes a smoothing Newton method which posesses global convergence and superlinear/quadratic convergence rate.Then,the numerical experiments verify that the proposed method successfully search Nash equilibrium of the noncooperative game model under the price cap.The results indicate that a suitable price cap ensures that generators and big users sign bilateral transaction contracts,which is helpful to promote the process of marketization.The price cap does not prevent the transaction between generators and big users,which means that there is a theoretical basis for the regulatory agency to implement the policy of price cap.With the formal implementation of renewable portfolio standard,the scale of transactions involving renewable energy in the electricity market is increasing and the competitive relationship among the trading parties has undergone major changes.Based on tradable green certificate mode originated from the renewable portfolio standard,this thesis constructs a leader-follower game model with multiple leaders among multiple power generators and independent system operator.As a leader,each power generator decides its power generation and predicts the decision made by the independent system operator based on the power generations of all generators.As a follower,the independent system operator decides the transportation at all nodes in the electricity market to maximize social welfare.By means of Karush-Kuhn-Tucker conditions,the game model is transformed into an equilibrium program with equilibrium constraints.Then,stationary systems of the equilibrium program with equilibrium constraints are discussed and the uncertain index systems are reformulated into equations with simple constraints.Finally,the global method is employed to solve the equilibrium of multi-leader-single-follower game model under the tradable green certificate mode.The results indicate that the leader-follower game model with multiple leaders is reasonable and the tradable green certificate mode is also effective.Our country needs to improve the related policies of green certificate,promote the implementation of the green certificate trading mechanism,and motivate the development of the green certificate market.