The Research Of Power Quality Comprehensive Evaluation Method

The rapid development of science and technology as well as national economy promote alarge-scale application and the popularization of sensitive electrical equipment, such ascomputer, power electronics etc., Simultaneously, as the power quality has a direct influenceon life quality and the overall efficiency of national economy, a continuously increasingdemands on it was aroused among the power consumers. Detecting and evaluating powerquality scientifically and reasonably makes an objective and accurate measure on the pros andcons of it, which will be conducive to the comprehensive control of power quality, therefore,itbenefits to establish a fair and balanced electricity market.Firstly, the paper introduces the individual indicators on power quality and elaborated theevaluation method of each single index. In addition, by analyzing and comparing the severalcurrent typical comprehensive evaluation methods on power quality that based on theorieslike “the fuzzy theory, the probability statistics and vector algebra, the neural network theoryas well as the grey theory”, the paper also points out the respective advantages anddisadvantages of each method.Secondly, the subjective and objective weight combining method was discussed. Thismethod adopts single weighting method to determine the weight of each evaluation index,afterwards, uses combinatorial weighting method to determine the comprehensive weights.Eventually, evaluation method that based on the probability and statistics as well as the fuzzymathematics was performed to realize the comprehensive evaluation on power quality.Finally, the paper put forward a comprehensive evaluation method of power qualitywhich based on consumer equipment classification statistics. The method classifies theelectricity consumers in the first place, then using fuzzy clustering analysis method todetermine typical consumers. By analyzing the electrical equipment quantity and energyconsumption statistics of typical consumers, on the basis of the emphasis degree of eachindicator and its proportion from electrical equipment to power quality, the analytic hierarchyprocess and energy weighting method was utilized to determine the weight of each evaluationindicator on power quality, thereby realizing the comprehensive assessment on power qualityof distribution network consumers.The evaluation cases indicate that the subjective and objective weight combining methodcan make an integrated comprehensive consideration of each power quality evaluation indicators, which makes the power quality evaluation on power grid side possible. Moreover,the comprehensive power quality evaluation method that based on customer equipmentclassification statistics, stands fully on the consumers’ perspective, was proved to be withstrong practicability and pertinence which creates a high credibility. Both the two methodscan achieve the comprehensive evaluation on power quality objectively and rationally.