Optimum Allocation Method Of Voltage Sag Monitoring Nodes And Fault Location Estimation

With the development of scientific technology and modern industry, it is an important work to the power quality due to the increasing use of sensitive equipment in power system. Voltage sags casued by short-circuit faults are the most serious problem in power quality which lead to malfunctioning or failure of power equipment. In order to sovle the problem and reduce ecnomic loss, it is necessary to establish a perfect and reliable system of monitoring voltage sags and fault locaiton. The idea of monitoring voltage sags is to detect the optimal location of monitoring nodes, using a minimum number of monitoring nodes to guarantee the observability of the whole system. However, the idea of fault location is to estimate the fault position and the faulted transmission line based on the optimal monitoring program.In order to capture all the fault positions of voltage sag in the whole system, this paper presents an approach based on particle swarm optimization (PSO) algorithm for optimal location of voltage sag monitoring nodes. The monitor reach matrix is built by using the solution of analytical expressions which are valid for any location of faults in the power system. A0-1linear programming model is proposed to solve the problem of optimum allocation, whose object function is to minimize the number of the monitoring buses and the key constraint is to guarantee the observability of the whole system considering any balanced or unbalanced faults. Using penalty function, the PSO algorithm is applied to solve the optimization problem. The best optimal locations of monitoring nodes are finally obtained by comparing the sensitive of buses. The effectiveness of proposed algorithm is verified by the case study based on IEEE-39standard test system.A new method based on optimal voltage sag monitoring program is proposed to locate any type of fault on transmission line. On the base of the improvement optimal location of monitoring buses, the fault position and the faulted transmission line are estimated by implementing the least squares method. In this estimation, only the voltage sag magnitudes recorded at the limited optimal monitoring buses are available measurements. The performance of the proposed method is illustrated in the IEEE39-bus test system, and the validity of such a method is testified.In order to locate the short-circuit faults on the base of monitoring voltage sags, another optimal location method of voltage sag monitoring nodes is presented. The monitor location matrix considering any type of fault is built in the case of replacing fault point by fault section. Then a0-1linear programming-based model is build to solve the problem of optimization allocation. The object of the optimization model is to minimize the number of the monitoring buses. And the key constraint is that the fault section of voltage sags can be locate accuratly and only considering any type of fault. Both the validity of such an optimal monitoring program and the accuration of the fault locating results are testified by their test and comparison.