Studies On Practical Methods To Calculate The Available Transfer Capability With Security Constraints In Electricity Market

In the context of electricity market, Available Transfer Capability (ATC) is an important indicator of the further usable amount of transmission capacity for commercial trading, which has a substantial impact on the successful operation of the electricity market not only from the technical viewpoint but also from the economical perspective. In this dissertation, we investigate the applicable methods for the assessment of ATC in practical environment. The main contribution of the thesis is focused on the five aspects as follows:First of all, an applicable scheme for assessing ATC among the different regions in a multi-region power delivery system is proposed under bilateral trading mode, which, utilizes three traditional distribution factors-PTDF, LODF and GODF, to analyze the incremental power transfer capability based on an accurate base flow considering the "N-l" static security constraints. Here, we consider not only the limitation of line thermal capacity and bus injection, but also the limitation of tie line's cutset dynamic stability among different regions.Then, a new mathematical programming formulation is developed, which keeps the validity of arbitrary existing transactions in the system while maximizing the prespecific generators and loads under all the physical constraints. The sequential quadratic programming (SQP) method is proposed to solve the problem. And then Benders decomposition is introduced to account for the static security constraints, each contingency is represented as a separate subproblem which is solved via the SQP method. Parallel scheme and series scheme are presented to deal with the subproblems.Thirdly, the Continuation Power Flow (CPF) method is applied to calculate initial value of ATC. Then a model for calculating the first order sensitivity of ATC with respect to the variation of the system parameters is presented. By this method, the new ATC can be estimated quickly when the corresponding parameters shifting away.Fourthly, an applicable method to compute the ATC with dynamic security is also presented. The strict Lyapunov energy function is constructed for the network structure preserving model and load model with the steady voltage character. Interpolation technique is used to estimate the ATC.Finally, the significations of TRM and CBM are discussed. A method to TRM calculation based on probabilistic model is presented. Then a concept called steady-state ATC region (SATCR) is proposed. Analysis demonstrates that the SATCR conducts a new idea to solve the problem of assessment for ATC. It can decrease the dimension of calculation remarkably.