Research On Locational Marginal Price Model Considering Full Cost Information

With the deregulation of the power industry and the continuous reform of the power market,the locational marginal pricing theory has been widely us ed in the power market as an important means of economic regulation,and it is necessary for the security constrained economic dispatch to grasp the locational marginal price quickly and accurately.The non-convexity of the power market can be caused by the economies of scale,the fixed start-up cost and no-load cost,and the inflexible dispatching capacity of the power market.In the presence of declining average costs or non-convexity,marginal cost pricing is flawed,for it would lead to inefficient al location and distribution of resources and could cause further inefficiencies because of the administrative mechanism used to cover losses.Although the loss cost is only a small fraction of the locational marginal price,it provides the power system with economic signals,which can improve the utilization rate of transmission network and optimize the allocation of power generation resources,as well as planning and construction of transmission network.In this paper,a pricing method model based on the non-convexity condition is proposed,which is modified by using the loss cost.The details are as follows:Firstly,a locational marginal price model based on security constrained economic dispatch is established.On the basis of economic dispatch,the influe nce of loss in transmission process on generation cost is further considered,and transmission constraints of lines are added.According to the different application methods of the locational marginal price in the day-ahead market and the real-time market,the mathematical model is modified based on the corresponding pricing rules.Then,an extended locational marginal price model based on the total cost information of the generator is established.The new constraints include full cost information which has the fuel cost,the starting cost and the no-load cost of the generator.The integer relaxation technique is applied to the extended locational marginal price algorithm.The results show that the model improves the non-convex pricing issue.At the same time,uplift cost can be minimized.The locational marginal price model is divided into a scheduling model and a pricing model to avoid the incorrect excitation signal under the non-convex condition.In the pricing model,the integer relaxation method is used to approximate the Convex Hull relaxation solution in the extended locational marginal price algorithm.Finally,an extended locational marginal price optimization model based on the total cost of the generator and the network loss cost is established.Th e power balance equation includes the loss cost,which is continuously modified by the iterative algorithm in the model.The distributed loss model is adopted to distribute the system loss,which solves the mismatch issue at system reference bus.On the on e hand,the results are compared with those of the ac optimal power flow algorithm and the lossless dc optimal power flow algorithm to ensure the accuracy and feasibility of the algorithm.On the other hand,the effectiveness of the algorithm is verified u nder the non-convex condition.In this paper,an extended locational marginal price optimization model is proposed.This model has been engaged to calculate the prices with the use of the total cost of generators and loss cost.The results show that the new pricing method can reduce the extra payment cost and provide a comprehensive and accurate price signal which can guide reasonable power consumption or investment planning.