The Research On Operation State Evaluation Technology Of Power Transformer

The evaluation process of transformer operation state is complex,the information of some evaluation indexes is complete,and some information is incomplete,so traditional white and black systems cannot be used for evaluation.The operation state of transformer involves many indexes.Different units of each index have different influence on transformer.How to find out the accurate evaluation method of transformer operation state is an urgent problem for power enterprises.At present,in the aspect of transformer operation state evaluation,power enterprises lack of objective and effective evaluation methods and means.Problems such as poor operation of transformer or sudden damage of equipment often occur,which affect the stability and safety of the whole power grid.In order to evaluate the operation state of transformer comprehensively,the grey theory model can be used to evaluate the evaluation indexes of operation state comprehensively.At the same time,according to the evaluation target of operation state,we can set the weight and threshold,get the positive and negative boundary of operation state,and use the grey theory model to get the prediction value of each index.Firstly,an evaluation system of transformer operation state based on electrical test,dissolved gas in oil,insulating oil characteristics and other insulation factors is constructed through expert questionnaire survey,and the evaluation score is changed from 9 point system to 3 point system,which simplifies the calculation amount of index system;secondly,the evaluation of transformer operation state is determined by grey model by using the fusion of secondary derivation formula and grey theory model The threshold boundary(positive and negative expectation boundary)of the index is represented by the second derivative formula.According to the index weighting adjustment in the later stage,the curve variation range drawn by the grey model is in line with the actual setting requirements,and the improved grey theoretical model is obtained.Finally,taking the 110 kV substation as an example,the index value of the operation state evaluation system of the power station is investigated.According to the aging rule of transformer,the stage of each index value is analyzed by using the improved grey theory model.According to the actual results of the operation state index,the maintenance frequency and key points of different equipment are set to ensure the stability of transformer operation.