Research And Design On Power Quality Simulation And Decision-making System

Problems about power quality were raised with the development of power network and modern society. It was also a new request for the research of power systems. Since power quality systematic application was not perfect, an integrative concept of power quality solution, viz. Power Quality Simulation and Decision-making System (PQSDS) was raised in this paper. PQSDS was designed to perform a continuous progress for Power Quality about monitoring, data integrating, analysis, decision-making and filtering. It consisted of a set of uniform, sequential and reasonable technique. With the development of PQSDS, researches have been done on harmonic source practical model, harmonic eliminating decision-making and power quality evaluation. The main contents are as follows:(1) Based on the central problems researched in power quality and requirement by fieldwork engineers, framework of PQSDS was brought forward. Main features of the system were carefully designed. Three phrase harmonic power flow and expert decision system was discussed in detail.(2) According to researches on harmonic source models, meanwhile, aiming at PQSDS development, a simple and practical model is raised. Main harmonic source, such as Three Phase full control bridge circuit, single phase capacitor filtering circuit and arc furnace, were concerned. The model balanced the simpleness and accuracy, and can satisfy engineering compute.(3) One of the main problems about power quality, viz. harmonic eliminating was analyzed. The way to choose the parameter of passive filter and active filter was given. The progress of expert decision to solve the problem was primarily discussed.(4) Smart client technology was inducted to PQSDS. It was combined with IEC61970 standard. It can provide data integration method including data flow, communication and application layer, so that various data obtained by different company and different devices can be consistently analyzed in one database.(5) A multi-level fuzzy comprehensive evaluation algorithm is proposed to evaluate PQ. The PQ standards are referenced and key factors that influence PQ are extracted. These factors are divided into two levels to assess PQ. By constructing membership functions for all the factors separately according to their characteristics and by determining the weights of each factor using improved Analytic Hierarchy Process (AHP), a model which can classify PQ into five grades is designed.