Study On Maintenance Decision Technology In Oil-immersed Power Transformer

Power transformer is an extremely important part of the power network,which plays the role of power conversion and transmission.The safe and stable operation of transformer directly affects the safety and stability of power network.Oil-immersed power transformer is a common type of transformer in power network.Faults of oil-immersed power transformers occur from time to time due to the influence of operating environment and aging of equipment.The existence of faults will greatly reduce the life of power transformer.After reasonable maintenance,its life can be greatly improved.Therefore,in order to improve the reliability and safety of products,fault diagnosis and maintenance decision-making technology is particularly important.First,the characteristics and thermal and discharge faults of oil-immersed power transformer are introduced.On this basis,summarize the current research status of oil-immersed power transformer maintenance decision-making technology,which lays a foundation for the following text.Secondly,the fault types of oil-immersed power transformer are described in detail,and the fault characteristics of oil-immersed power transformer are summarized to form the corresponding relationship between the fault types and each feature quantity.Furthermore,the basic principles of risk assessment and its common problems are described.On the basis of risk assessment,an effective fault analysis process is established for oil-immersed power transformer fault magic and impact analysis.Further,on the basis of fault diagnosis and risk assessment of oil-immersed power transformer,the overall failure probability of transformer system is calculated,and the corresponding relationship between failure and symptoms is established.This paper establishes a transformer fault tree model by means of fault tree analysis,analyses the difference of transformer comprehensive failure probability at different time of bottom event,and puts forward a calculation method of transformer comprehensive failure probability.The validity of the fault tree and the comprehensive probability calculation method is verified by the transformer data.Considering that transformer status maintenance decision involves many decision-making evaluation indicators,the evaluation of these indicators is often made by field experts or engineering technicians.Their evaluation cannot be measured by a strict judgment standard,but is a fuzzy concept.For this reason,the author introduces fuzzy decision into transformer status maintenance decision,puts forward a method of fuzzy multi-attribute decision making to analyze transformer status maintenance decision,and studies the decision-making index and maintenance scheme.Through specific examples,the maintenance schemes are evaluated by using the fuzzy simple weighted average method and the fuzzy multi-attribute compromise decision method respectively,and consistent conclusions are obtained.