| Transient stability constrained optimal power flow (TSCOPF) is an effective measure to coordinate the dynamic security and economic of power system. It is a big challenge of power system’s safe operation. It has been paid great attention by a large number of researchers.The thesis has constructed TSCOPF model in polar coordinate to avoid the complexity of electromagnetic power equation in mixed coordinate. Power flow equation and electromagnetic power equation are unified into polar coordinate. The model is more convenient for memory and programming. In order to improve the computational speed, the thesis has proposed TSCOPF model based on three-step implicit Adams method. The three-step implicit Adams method is with fourth order accuracy and big step. It can effectively reduce the dimensionality of TSCOPF problem. Reduced-space interior point method, which is the combination of reduced-space approach with primal-dual interior point method, is used to solve the problem. The method has made full use of reduced-space approach to reduce the computational time caused by the correction equation, so as to improve the computational efficiency and reduce the memory usage.Critical Clearing Time (CCT) is an important parameter to judge transient stability. The thesis proposes dichotomy with variable step to solve CCT for screening the expected unsafe contingencies. Compared with dichotomy with fixed step, the method can use a bigger step according to an update strategy when they achieve the same computational accuracy.Numerical simulations on the six systems, from9to3301buses, have shown that reduced-space interior point method is with high computational efficiency and less memory, and suitable to solve large-scale TSCOPF. Compared with implicit trapezoidal method with a small step, three-step implicit Adams method with a big step can improve more than five times of computation speed. The proposed method is close to the level of online application. |
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