Research On Power Quality Evaluation System Based On Blind Number Fuzzy Set

With the rapid development of smart grid,more and more distributed generation devices are connected to the grid,which brings new challenges to the comprehensive evaluation of power quality.Power systems have more uncertainty index such as dynamics,randomness,fuzziness,grayscale and some other unknown factors.Traditional power quality assessment methods can not meet the current practical needs.In this paper,a comprehensive evaluation method of power quality based on blind number fuzzy sets is proposed,and the method is applied to the comprehensive evaluation of power quality system.This paper analyzes the existing evaluation methods at home and abroad,and deeply studies the application status of the blind number theory and variable fuzzy set,and combines the two to obtain the blind number fuzzy set comprehensive evaluation model.The model combines the randomness and grayness of the blind number theory with the dynamic and fuzzy nature of the variable fuzzy set.The blind number theory is used to process the indicators of power quality to obtain the blind number interval,and the variable number interval is used to calculate the variable.The interval value of the relative membership function of the fuzzy set,the interval and credibility of the blind number theory are used to describe the relative membership degree of the variable fuzzy set,and the qualitative concept of evaluation level is converted into the interval quantity representation.The simulation results show that the experimental results obtained by the blind number fuzzy set model are more objective.The final weight of each index of power quality is determined by cooperative combination optimization method.The weighting results of typical subjective and objective weighting methods are combined,and the final weight of each index is obtained by using the idea of minimum deviation of each weighting method.Complete the comprehensive assessment of power quality.According to the weight result and the relative membership degree interval,the comprehensive membership degree interval of each index is determined,and the power quality comprehensive evaluation is completed by the calculation of the level feature vector of the variable fuzzy set.A real-time power quality evaluation system based on B/S mode is developed,which enables users to evaluate the power quality information of a specific evaluation point in real time through the Internet and browser,and to view the historical evaluation data at any time to form a power quality evaluation report,which provide reference for quality pricing for the power quality market.