The Influence Of Direct Power-purchase For Large Consumers On Profit Distribution In Power Grid

From the last round of the electric power system reform so far,direct power-purchase for large consumers is the most important attempt of power market transactions,which is propitious to further improve the service and the operation efficiency of grid corporations,to form a reasonable price mechanism and risk-sharing mechanism,and to develop and perfect the competition mechanism of power market.On the one hand,although the direct power-purchase involves the adjustment of the existing pattern of interest,there is no detailed and comprehensive analysis because the current direct power-purchase theory is not yet mature.On the other hand,with the advance of reform,the responsibilities and interests of power generation enterprises,grid corporations and power users become clearer,thus market players hope to clarify the impact of direct power-purchase on grid profit distribution.However,the present economic accounting method of grid corporations can only reflect the overall profit and loss situation.If the profit changes of every part in grid before and after direct power-purchase can be quantitatively and detailed analyzed,the precise economic dispatch and regulation as well as direct power-purchase related policies can be provided a strong foundation.In this paper,the concept of profit distribution in power grid and a method to calculate the profit distribution are proposed.Firstly,a bi-directional tracing method for multi-source multi-load loop networks is proposed.Based on the power component theory and branch equivalent conversion,the power-supply-networks and load-derive-networks can be worked out,which is the physical basis of profit calculation.Secondly,with tracing results and economic accounting well matched,the economic models of nodes and branches and economic distribution models in grid can be established in accordance with the cost conservation principle.Lastly,“Profit Distribution Surface” and “Profitability Contours” are graphical descriptions of profit distribution in the whole network.This method realizes the matching of energy and economy,with which the local interests of the power grid can be accurately reflected,and the profit distribution characteristics can be intuitively,meticulously and vividly depicted.The method proposed above is used to study the profit distributions of the IEEE 39 bus system before and after direct purchase,and to quantitatively analyze the changes of the interests of all parties in the market.It shows that the direct power-purchase will affect the profits of all market players,and the current “Dual-Track System” allocation method of benefits is a “compulsory” one,unfair in a certain extent.Therefore,it is necessary to study and formulate a more reasonable policy of direct power purchase,so as to balance the interests of all parties in a better way.