| Converter transformer is the key equipment in HVDC systems,as the growth of the HVDC project operating life,has been put into operation of the converter transformer aging problem is increasingly outstanding.For a long time,the main maintenance for power transformer is periodic maintenance,which is regardless of converter transformer’s condition in service and will lead to "over maintenance" or" owing maintenance".With the development of condition monitoring technology,condition-based maintenance which ground on condition assessment becomes an inexorable trend to replace periodic maintenance.Therefore,in view of the health status evaluation of converter transformer and residual life prediction accurately,thus enffectively equipment maintenance plan reasonably,have important theoretical meaning and engineering value.Based on this background,this paper combined with the science and technology project of CSG EHV power transmission company "Study of Condition Evaluation and Life Prediction for Convertor Transformer",carried out health status of converter transformer and residual life evaluation research work.This paper mainly in four aspects to carry out the research:analyzing the converter transformer health state evaluation index system containing of state parameter before and after the operation,research of health status evaluation model of converter transformer based on fuzzy comprehensive evaluation method,research of lifetime prediction model of converter transformer based on health index and failure probability and development of converter transformer health condition assessment and life prediction system.In this paper,the main research contents and achievements are as follows(1)Starting from the basic composition of converter transformer and first proposed bringing the converter transformer critical raw materials,factory test,transportation and installation records before the operation of converter transformer into the evaluation system.Then selected a number of indicators which reflecting the healthy state of converter transformer accurately to establish a systematic and comprehensive health evaluation index system.Has made a definition to the life of the converter transformer,analyzed the service life of converter transformer characteristic curve and introduced the three major factors affecting the service life of converter transformer in detail.(2)Taking operation time as the cut-off poin,combining the fuzzy theory,to set up the classification health status evaluation model of converter transformer.Assessed the health condition of converter transformer before and after the operation and gived the comprehensive evaluation results.At last through an example in Tianshengqiao convertor station,the feasibility and credibility of the model are proved.(3)On the basis of the converter transformer health condition evaluation,calculating the converter transformer ageing health index,and according to the three major factors affecting the service life of the conveter transfomer,and failure probability calculation based on the comprehensive health index model is set up.According to the local power grid as a result,the converter transformer failure rate changes over time of Weibull distribution curve are fitted.Based on this,advances a new notion as conditong degree of reliability,establishes the reliability of the converter transformer based on the life prediction model of converter transformer residual life prediction.(4)According to the established health state evaluation model and residual life prediction model,completed the converter transformer health condition assessment and life prediction of the system software design and development,and put it into test,the results meet the expected requirements and has great engineering practical value. |
