Research On Transformer Reliability Based On Fault Tree And Electrical Test

The stable operation of the transformer is very important to the power system.At present,the transformers in the power grid are basically adopted with no differential periodic maintenance mode,and this wasted a lot of manpower and material resources.In view of this situation,this paper systematically studied the fault condition of the transformer,which provided certain theoretical support for the maintenance of the transformer.Firstly,this paper studied the current state maintenance method and state evaluation method of transformers,and a lot of literatures were read,and analyzed the current research status at home and abroad.The statistical analysis of the actual transformer operation of Dalian Power Grid was carried out.It was pointed out that there are many old-age transformers,and it was necessary to check the operation of the old transformers.Secondly,the fault condition of the transformer was deeply studied.At present,the fault types of the transformer were complex and diverse,and the fault condition classification was also different according to different standards.In order to show the fault condition of the transformer more intuitively,this paper started from the fault phenomenon,and divided the transformer fault into heating fault,insulation fault and mechanical fault,and analyzed the influencing factors of each fault carefully.Then,combined with the current maintenance methods in the power grid,several methods for transformer state maintenance were studied,including DC resistance measurement,dielectric loss factor measurement,frequency response measurement,oil decomposition gas measurement,and combined with examples.The effects of the measurement methods were described.Finally,based on the research on transformer fault,the fault tree model of the transformer was established.The fault of the transformer was divided into five parts according to the components,which was the intermediate event of the fault tree,and the bottom event of the fault tree was established accordingly.According to the fault tree model of the transformer,combined with the fault statistics of the substation,the reliability of the transformer was evaluated.The average fault-free time of the transformer and the failure rate of each component of the transformer were obtained.According to the analysis results,it is proposed to adopt different maintenance cycles for different regions,and adopt different maintenance plans for different test methods,thereby improving the efficiency of maintenance and saving manpower and material costs.Through the research in this paper,we can have a systematic understanding of the faults of the transformer and its maintenance,and optimize the maintenance plan of the transformer,which has certain guiding significance for the stable operation of the transformer.