The Study And Design Of Network Topology Algorithms

Network topology analysis is one of the most essential parts of Energy Management System (EMS) and Distribution Management System (DMS). The research on it has important theoretical and practical value. It is also the foundation of other advanced application software of EMS and DMS. As a basic common module, its reliability and rapidity directly influence the performance of EMS and DMS.This paper analyzes the two methods for topology analysis: matrix method and searching method, which are in common use. After in-depth research and analysis of Gaussian elimination process of solving the power network equation, this paper proposes a network topology analysis method that replaces admittance matrix with adjacent matrix and solves equations with logic operations.If current is injected to the electric network at only one node, the voltages at the nodes in the same electrical island as the injected node are not zero; otherwise the node voltages are zero. Solving node equations of the network can find all electrical islands in the electricity network, so this method can be used to complete the analysis of electrical island. Bus analysis and electrical island analysis are same in mathematics, so this method can be applied to bus analysis. Topology analysis is concerned only about the connections between nodes, so it can be used to replace admittance matrix with adjacent matrix and solve equations with the logic multiplication and logic addition operation rules. Meanwhile, according to the sparse of adjacent matrix and sparse technology, this paper uses non-zero storage, non-zero operation and node optimizing ordering in the process of the calculation to improve the efficiency of topology analysis for large-scale network. In addition, value assignment for current vector is based on the upper triangular matrix after Gaussian elimination, so the forward substitution computing is unnecessary. This method only needs to do back substitution, which can reduce the calculation time.In the partial topology analysis, the calculating time of whether the electrical island would split is relatively large. This paper proposes finding articulation point buses and articulation point branches through the overhang branches and overhang points; if the articulation point buses split, the electrical island will split, too. Following the articulation branches, the articulation point buses whose grade are lower than that of split articulation point bus could be gotten. Then these buses form a new electrical island. The remainder nodes of the old electrical island form the other new electrical island.Numerical examples show that the proposed topology analysis method which is based on solving equations can meet the speed demand of real time network topology analysis and the designed partial topology analysis can effectively increase the speed of the partial topology analysis.