The Algorithm Analysis And Application Of Imputation Of An Impedance-Branch Dissipation Power

In a sinusoidal steady-state circuit, how much of an impedance-branch dissipation power should be assigned to each source? To answer this question is not only a theoretical problem, but also concerns the solution of grid's security and economy problem, such as congestion management and available transfer capability(ATC). However, it is difficult to obtain a unique and common consent answer because of the nonlinearity of power expression.This thesis is supported by National Natural Science Foundation of China and Hunan Natural Science Foundation projects. The model and algorithm of branch's dissipation power component are studied as well as its application in fixed cost allocation, congestion management and available transfer capability.For power network with arbitrary configurations and multiple sources of the same frequency, the definition of branch's dissipation power component is given. According to this definition, the current widely used methods for branch's dissipation power component are investigated deeply. The merits, defects and applicability of the existing methods are analyzed in details. Example systems show that the weakly conditioned imputation of an impedance-branch dissipation power which is derived mathematically by the three weak conditions of Shapley value, satisfies the definition of branch's dissipation power component fully, which lays good foundations for its application in electricity markets.Under electricity markets with many kinds of transaction modes such as pool modes and bilateral modes, a novel method for describing the relationship between transaction power and bus power is presented. This method is applicable for all transaction modes. Based on the algorithm of branch's dissipation power component, the dissipation power is imputed simultaneously and naturally to individual transaction, which makes the driven function of branch's dissipation power on transactions clear. Simulation results show that the proposed algorithm is effective.Based on the algorithm of branch's dissipation power component,an accurately analytical method for imputing power flow naturally and simultaneously to individual transaction is derived mathematically, where transaction power is an independent variable. Both the fixed cost and the imputation of branch power flow to transaction are analyzed to develop a concrete method for imputing fixed cost to individual transaction. The proposed method is applicable for electricity markets containing pool and bilateral transactions. It satisfies electric circuit laws and provides economic signals to users. Simulation results show that the proposed algorithm is effective and feasible.The congestion management problem under hybrid transactions modes is investigated based on the algorithm of branch's dissipation power component. Then both the importance of transaction and the imputation components of active-power on impedance-branch are analyzed, and a concrete method for transaction control to eliminate line congestion is developed. Compared to the sensitivity analysis approach to transmission congestion management, this method is independent of swing bus, therefore, it could eliminate the error resulted from the sensitivity analysis approach and ensure the accuracy and uniqueness of congestion management scheme. Simulation results show the proposed algorithm is effective and feasible.The loadability of EHV and UHV transmission line is analyzed based on power circle. And then the dynamic reactive power compensation at middle of EHV and UHV long-distance transmission line is studied. A new method for calculating available transfer capability considering angle stability and voltage stability is presented. For the problem that the expressions of angle stability and voltage stability constraints are complex, this method deduces a simplified formulation of line transfer stability limits based on power-circle. Results show that when a transfer takes place in the system, at least one line reaches its transfer stability limits before the instability occurred. Then it is integrated into standard optimal power flow formulation, and a new ATC model considering angle stability and voltage stability could be established.In view of the expressions of security and stability constraints for transmission lines in ATC model are complex, an approximate linear expression in which the generator power outputs serves as control variables is given, and an optimal power flow model is built. Both are based on the algorithm of branch's dissipation power component. The constraints with different linearity in new model are solved by an approach that combines successive linearization with piecewise linearization. The security and stability constraints of transmission lines are considered directly in the solving process in order to avoid the low-efficiency of both model and solution because of the passive calibration and modifying working constraints in Newton method. Simulation results show that the proposed model and algorithm could improve the convergence of optimal power flow as well as speed up the solution process.