Study On The Method For Congestion Cost Allocating In Power Market

With the penetration of electrical power market reform and open transmission access, power transactions will increase progressively, which makes the operating conditions complicated and intensifies the unpredictability of power flow distribution and system stability, especially during the practice of national interconnection and west to east power transmission project. Because transactions are oriented to maximize profits, it is inevitable that low-priced lines bear much more power flow, low-cost generators make much more output, which cause the transmission congestions. This thesis makes systematic and thorough studies on problem of congestion cost pricing, tries to improve the method for congestion cost allocation so that the allocation results reflect contributions of market members on transmission congestion, make transmission network be used effectively and alleviate transmission congestions. Based on comprehensive references, this thesis analyses the causation and characteristics of transmission congestion in power market, summarizes methods for alleviating transmission congestions and the effects of congestions on power market. By analysis and compare on congestion management models under different power market modes, aiming at the congestion cost problem, the paper chooses a optimal power flow model which makes minimization of re-dispatch cost as the objective function. The principles of congestion cost and properties that congestion cost allocation method should has are elaborated. Thoroughly probes are made on the shortcomings of nodal price method and shadow price method. Employing the advantage of game theory on cost allocation problem, by means of Shapley value method, the average marginal contributions of lines on system congestion are got which have much more equity on congested line pricing, i.e. improved shadow price method. Loads'and bilateral transactions'contributions on congested lines are got respectively, through calculating of line load distribution factor matrix for load and line share of transaction under unconstrained case for transaction. All the models are verified with examples and satisfactory results have been obtained. It is proved that the proposed congestion cost allocation strategy satisfies the requirements of additive, monotonic and consistency.