Status Maintenance Of 220KV Substation Transformer

With the further deepening of the power grid reform,the grid structure is gradually expanded,and more stringent requirements are put forward for the safety and stability of equipment.As an important part of the power grid,the operation performance of the transformer is related to the normal operation of the power grid.Therefore,the research on the condition maintenance strategy of the transformer is of great significance to the safety and reliability of the power supply of the power grid.In this paper,through in-depth analysis of transformer fault types,influencing factors,and status information,and studied methods such as analytic hierarchy process,fuzzy comprehensive evaluation and D-S evidence theory.First of all,according to the status information of the equipment operation monitoring by the intelligent status monitoring system of the substation,including electrical characteristics monitoring information,insulating oil analysis information,gas chromatography monitoring information and winding frequency response characteristics analysis,a transformer state evaluation system is constructed.Secondly,through the fuzzy comprehensive evaluation method,the evaluation target is regarded as a fuzzy set composed of multiple factors.The factor set,comment set,and weight set are established in sequence,and a fuzzy matrix reflecting the membership information of each influencing factor and evaluation level is obtained.And apply the analytic hierarchy process to establish the multi-level structure and the comparison judgment matrix between the influencing factors,and conduct the consistency test to avoid conflicts in the judgment of the relative influence degree of the influencing factors.Established a transformer state model based on evidence theory.And improve the basic probability assignment rules of D-S evidence theory to fuse the evidence body.Then,according to the initial investment cost,operating cost,failure cost,maintenance cost and depreciation cost,the transformer life cycle cost model is established,and the transformer life cycle management is implemented,and the inflation rate and interest rate are introduced to improve the accuracy of the model.Finally,the conditional maintenance decision-making framework is constructed with three parts: the information evaluation layer,the maintenance strategy layer and the maintenance decision-making layer.The maintenance strategy is composed of the maintenance method and the maintenance time,and used as the identification framework of the evidence theory.Taking the economy and power supply safety demonstrated by the life-cycle cost as decision-making indicators,construct a transformer condition maintenance decision-making model based on D-S evidence theory.Taking the economy and power supply safety demonstrated by the life-cycle cost as decision-making indicators,construct a transformer condition maintenance decision-making model based on D-S evidence theory.