Fast Calculation Of Probabilistic Insecure Index And Optimization Of Operating Costs Based On DSR

With the fast developing of global economics, united power system has satisfied the user demands. Meanwhile, hidden troubles are caused in the operation of bulk power system by the complex and variability of network topology.Traditional security analysis is usually point to point method based, which can only provide binary information about the system states. However, the method above will induce the computational burdens and time consuming which are hardly to be endured, thus, the results are not desirable. By the idea of dynamic security region(DSR), the problem can be transferred to analyze that whether an operating point is inside a region when faced with a disturbance. Besides, DSR can give the quantitative index of security assessment, such as security margin and probabilistic insecure index(PII).This paper proposes the rapid calculation method of probabilistic insecure index based on angle spin. First, large amount of simulations are performed for DSR and its boundaries upon various fault point of transmission lines. As a result, boundaries of DSR for different fault points are approximately parallel and the angle exists among the boundaries. Secondly, with the fault point occurring at head of the line stretching into the end, each angles formed by hyperplanes and reference one changes in linear.Therefore, according to the law above, we can first calculate the DSR hyperplanes at both the head and end of the line by matching method. Then, according to the linear law among coefficients of each hyperplane, probabilistic insecure index are quickly obtained on various fault points. Take WSCC4-11 bus test system as an example: probabilistic insecure index are almost same and maximum overall error is only 2.84%. The computational time consuming is 15.39% times of traditional matching method. Meanwhile, more complicated, higher dimensions the system is, the more obvious the advantages of angle spin method takes over.Through fast calculation of PII, the transient states of systems are also fast recognized. If the emergency control is needed when fault occurs, the cost of both the normal operation and measures taken for emergency control should be considered. Thus, this paper proposed the optimal power flow model, in which the total expectation of system is selected as the objective function and the probability of anticipate faults are added. The total cost can be divided into two parts: normal operation and optimal emergency control, both of which are integrated into objective function as each occurrence probability. 10 generators – 39 bus test system demonstrates that the total cost determined by the model proposed by this paper is 12% less than traditional optimal power flow model with various transient states consideration as constrains.