Reliability Evaluation Of Transformer Considering Aging And State Evaluation

Currently,in addition to the power grid fault,we should pay more attention to the fault of power equipment.The stability of the power grid is based on the safe operation of power equipment,especially the transformer,which is the core equipment of the power system,its running state affects the security and stability of the power system directly.There are many methods about the evaluation of transformer and there is constantly room for improvement.Besides,the comprehensive method which combines the long term life evaluation with the short-term state evaluation is lacking.In this paper,based on the existing methods,the improved algorithm is used to evaluate the reliability of the transformer.First of all,this paper calculates the equivalent life loss and remaining life of transformer,considering the influence of data acquisition frequency,environment temperature and load.The remaining life of transformer is calculated by combining the expected total life with equivalent life loss.The accuracy of the method is proved by the example analysis.Secondly,state evaluation methods are summarized,the hierarchical process is done based on the national grid evaluation procedures and Fuzzy AHP method is used to determine the weights of each layer elements to get the transformer state evaluation result.The accuracy of the method by a practical example is proved in the end.The fuzzy analytic hierarchy process(AHP)is a new attempt for transformer condition evaluation,which provides a new approach for transformer condition evaluation.Finally,failure rate function model is established in this paper by the boundary conditions and trend analysis considering the remaining life and state scoring and the parameters of the model is fitted by the least-square method.The rationality of the proposed model and the accuracy of the fitting method are verified by the calculation results of a series of data.