Research on Working State Evaluation Method of Transformer Based on KPI Assessment Index System

The multi-level evaluation method for fuzzy comprehensive evaluation of transformer operation state based on the key performance indicator (KPI) is studied. Firstly, the KPI method is used to build the key evaluation index system of power transformer, and the status index and evaluation grade of transformer are determined; Secondly, The Analytic Hierarchy Process (AHP) set pair analysis method is introduced into the multi-level evaluation strategy of transformers. The relative deterioration degree is used to characterize the relative deterioration degree of the transformation from the actual state of transformers to the fault state, and the membership degree and relative deterioration degree functions are constructed to describe the uncertainty of the operating state of transformers; Finally, a comprehensive evaluation matrix is constructed to evaluate the evaluation factors at all levels of the transformer in combination with the weight of the evaluation index, and the evaluation results of the transformer are quantified to obtain the operation status of the transformer. The example analysis shows that the multi-level state evaluation method of power transformer based on KPI can effectively and accurately evaluate the operation state of transformer. This method can effectively improve the evaluation level of the health status of power transformer, provide assistance for the stable operation of substation, and provide effective support for the safety of the power grid.