Research On Condition Assessment And Maintenance Strategy Of Power Transformer Based On Multidimensional Cloud Model

In recent years,China's power grid access load presents the characteristics of diversification,strong randomness,large fluctuation range and increased complexity.The safe and stable operation of power system is constantly subject to new impacts and challenges.Power transformer,as the most important pivotal link in power transmission and transformation system,provides a strong support for ensuring the reliable operation of the system.How to quickly diagnose and identify potential risk points of power transformers in the operation process and adopt corresponding maintenance strategies,and at the same time to minimize the various risks caused by overmaintenance,is a key research topic of the State Grid Corporation of China,which is also the main research content of this paper.Firstly,this paper studies the transformer winding deformation fault,establishes the transformer winding deformation fault simulation model,analyses the main characteristics of transformer winding deformation fault,and analyses the state feature extraction strategy of transformer fault diagnosis based on vibration signal and running current signal,and puts forward the method of using transformer vibration signal and current signal to process transformer fault diagnosis.The intrinsic mode function(IMF)derived from Expirical Mode Decomposition(EMD)decomposition is used as the criterion to determine the abnormal operating conditions of power transformers.Through case diagnosis analysis,it is proved that the strategy can significantly improve the accuracy of diagnosis and effectively improve the diagnosis effect of transformer mechanical fault.Secondly,the paper studies the establishment principle of power transformer operation condition rating system.Oil chromatographic index,electrical index,insulation deterioration index and short-circuit electrodynamic force index are used as evaluation factors for power transformer operation conditions.A power transformer evaluation model based on multi-dimensional normal cloud model is established.The non-fault operation conditions of power transformer are divided into five types.The weight of each index of power transformer is determined by using the entropy weight method.The state evaluation factor is combined to realize the state evaluation of power transformer,and the corresponding maintenance strategy is further determined.Finally,based on the historical operation data of three 110 kV transformers of the same type in Quanzhou A,B and C substations of Fujian Province,the paper uses the state assessment model proposed in this paper to analyze them,and verifies the scientificity and effectiveness of the state-based maintenance strategy for power transformers designed in this paper.