Optimization Of Voltage Sag Fault Source Localization Algorithm

Power quality determines the safety and reliability of electrical equipment in people's life and production' process, voltage sag becomes the most serious factor which endangers the stability of power quality because of its short duration,frequent and strong randomicity. This dissertation analyzes the current domestic and international mainstream voltage sag fault source localization algorithm, does further study of voltage sag source localization algorithm and fault monitoring device allocation scheme's details and principle, it concludes that the main factors influencing the location accuracy and speed. Network node impedance matrix in the system which is as the foundation for localization algorithm, its solving steps are complex and inaccurate. The number of voltage sag fault monitoring device is too big that will produce too many redundant feedback data, thus increases the computation redundancy. Judgment of localization algorithm is too singleness and the number of iterations is too much, these two reasons affect the accuracy and efficiency of the localization algorithm. The main work of this dissertation is as follows:First, research network node impedance matrix algorithm. The dissertation does optimize to the transitional matrix method because its advantage of dealing with the mutual inductance data, joins grounding branch to the algorithm steps to resolve the error due to ignore the grounding branch, and the dissertation rebuilds the topological structure of power system by depth first search to reduce the difficulty of calculating complex circuit data, thus improves the accuracy of basic data and its solving speed.Second, research the fault source monitoring device allocation scheme. The dissertation optimizes the scheme based on exposed area, limits the precision of exposed area to node level, solves the problem which triggers repeated or missed monitoring device allocation. Then the dissertation builds the node exposed areamatrix based on above research, and this makes the allocation scheme can be solve by Integer linear programming. The problem of detecting the whole power system by a few of voltage sag monitoring devices can be solved by calculating the linear programming model, thus the allocation scheme optimization of fault monitoring device can be completed.Finally, research the localization algorithm. Establish a comprehensive judgment which contains fault source type analysis, fault source orientation judgment and virtual point localization method. Based on fault power system disturbance amplitude judge the fault point location in the system relative to the monitoring location. The fault type of analysis results and the fault location be used to optimize the virtual fault point positioning method, which can reduce the number of iterations. Based on the above research, this dissertation presents a multiple virtual fault localization method which can solve the problem of positioning is not accurate and get the accurate and efficient voltage sag fault source localization method. Matlab be used to locate the simulation to prove the effectiveness of the optimization algorithm.