The Research Of Power Quality Comprehensive Evaluation Method And Comprehensive Evaluation For Regional Grid

With the advance of society and science technology,more and more electronic devices and nonlinear devices have been used,leading to serious distortion of voltage and frequency in distribution network,that is power quality to be destroyed.Therefore,it is meaningful to research judgment method of power quality to power consumer.Detecting and evaluating power quality scientifically an reasonably makes an objective and accurate measure on the pros and cons of it,which will be conducive to the comprehensive control of power quality,therefore,it benefits to establish a fair and balanced electricity market.First of all,the thesis studies the definition,national standard and concept of power quality,as well as research judgment method status of power quality at home and abroad in detail.Through the introduction and statement of researching background of power quality,and the description of the problem caused by power quality damage,thesis draws a conclusion that is the importance of power quality judgment.The thesis also introduces the concept of the every judgment index of power quality and its effects in detail.Secondly,the subjective and objective weight combining method was discussed.This method 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 fuzzy mathematics was performed to realize the comprehensive evaluation on power quality.Finally,The concept of power quality comprehensive evaluation(PQCE)for regional grid has been proposed.The regional grid power quality has been analyzed in hierarchy.First,the PQCE of each substation bus has been done by genetic projection pursuit method(GPPM).Then the weights of the GPPM comprehensive evaluation outcomes were proposed by the eigenvalue weighted method.The PQCE results of the regional grid and its each voltage level and each substation can be acquired by the weight.The power quality of regional grid can be reviewed from the local to overall by means of this evaluation results.Based on actual monitored data,essay gives the practical example analysis.It turns out that the method of power quality comprehensive judgment what is proposed,can achieve the power quality comprehensive considerations simply and effectively.