Methods Research Of Optimal Allocation Of Power Quality Monitors Based On Adaptive Genetic Algorithm

With the progress of science and technology and the development of electricpower system, demands of power quality is higher for both sides of the power supplyand utilization, power quality problems are increasingly attented by the power supplydepartment and scholars both at home and abroad. The voltage sag is the eventscontinually happened, huge dangerous, often complaint by users of power qualityproblems, power quality problems will be improved by monitoring voltage sag. Themost ideal method to monitor voltage sag is installing one power quality monitor oneach node of electric power system, so that we will be able to capture every voltagesag event which may occur in the power system. Due to constraints of economic costand the technical level, power quality monitors can’t be set on each node at present,therefore, it needs to optimize the configuration of the power quality monitors. Theresearch is based on genetic algorithm for optimal allocation of power qualitymonitors. The main contents as follows:(1) According to the requirement of the optimal allocation of power qualitymonitors, adaptive genetic algorithm is used to optimize the configuration of thepower quality monitors. The method realizes that the voltage sag is all observable,and guarantees the diversity of scheme of optimal locating monitors.(2) Aiming at the basis genetic algorithm, its implementation steps are focusedresearch, including encoding, selection strategies, crossover operation and mutationoperation, fitness function and Setting of constraints. The basic theory of adaptivegenetic algorithm and improved adaptive genetic algorithm is analysed.(3) On the basis of the principle of voltage sag, the calculation method of voltagesag is detailed analyzed, including calculating voltage sag caesd by different faulttypes happend in different positions. Voltage sag value is calculated by nodeimpedance, this method is simple. Three sequence impedance matrix obtained bysymmetrical component method is caculated for voltage sag value. The calculation ofvoltage sag occurred on the lines in electric power system was deduced, which canrealize observed area of power system can be broader.(4) A mathematical model for optimal allocation of power quality is established,including setting the objective function which the number of monitors is least andconstraint condition which the entire network can be whole observed. Power system observability is analyzed in detail baesd on the voltage sag. The adaptive geneticalgorithm was applied to the optimal configuration model of monitors, A optimizationconfiguration model of power quality monitors baesd on adaptive genetic algorithm(GA) is set up. Aiming at the shortcomings of the adaptive genetic algorithm,evolutionary attenuation factor is used for adaptive genetic operation, and the optimalpreservation strategy is adopted to improve the performance of the algorithm.According to the voltage sag observable redundancy, optimal solution evaluationprinciple is proposed for assessment of multiple solution, to determine the optimalallocation scheme of the monitors.At the end, the paper test the proposed optimization method on IEEE30nodesystem by MATLAB programming. Results show that this method can effectively getthe optimized configuration scheme of power quality monitors, the improved adaptivegenetic algorithm not only convergence rate is fast, and it is not easy to fall into localoptimal solution, and shows the superiority of the method and is feasible for theoptimal allocation of power quality monitoring.