Research And Design Of Condition Evaluation System For Large Oil Immersed Transformer

In the power system,transformers occupy an important position,and their operating conditions will affect the systematic operation of power equipment and the stability of the power grid.Transformer operation failure will affect the stability and safety of the power system.The traditional periodic maintenance method has obvious shortcomings and cannot match with the high demand for electricity in practice.Condition maintenance is a new tool in the field of transformer maintenance,and condition assessment is the basis for the decision of condition maintenance.Scientific condition assessment of transformers can accurately reflect their health condition,which has become an important topic of research in the academic field.Based on this background,this thesis takes the condition assessment system of large oil-immersed transformers as the research object based on information technology with modern characteristics,analyzes for 750 k V transformers and takes the initiative to solve the existing problems of the current work.The main work is as follows:1)This thesis analyzes the requirements of the large oil-immersed transformer condition assessment system in three aspects: functional,non-functional and authority management.This thesis constructs the condition assessment model of large oil-immersed transformer by introducing the combined hierarchical analysis method and adopting the improved D-S evidence theory method,and verifies the application and analysis of the above condition assessment method through the 750 k V transformer example,which proves that this theoretical method and the condition assessment model have the feasibility of engineering application.2)Starting from the working mechanism of transformers,the analysis technique of dissolved gas in oil is used as the basis for fault diagnosis of large oil-immersed transformers.The composition of characteristic gases and the correspondent relationship between different types of faults and the composition of oil and gas they contain in this state are analyzed.The three-ratio method has been adopted for fault diagnosis of poorly operating transformers,and the effectiveness of the method has been proved by analyzing and verifying the fault diagnosis examples of transformers.3)The B/S structure system,J2 EE architecture,MVC design pattern,SQL Server database,Java language and other technologies are used to apply condition assessment and fault diagnosis algorithms to complete the design and implementation of the condition assessment system for large oil-immersed transformers.The designed system can carry out condition assessment and fault diagnosis for large oil-immersed transformers.The main functions of the system include rules and regulations management,equipment operation and inspection management,condition assessment management,fault diagnosis management,comprehensive information statistics and analysis management,and system management,etc.