厄瓜多尔科卡科多-辛克雷水电站1号机定子绕组局部放电问题分析OA

The online partial discharge(PD)of the first generator,which has been operating for two years in the CoCa Codo Sinclair(CCS)Hydropower Station in Ecuador,was larger than that of the other generators.To analyze the reasons for the excessive PD,four offline PD detection tests were conducted from 2019 to 2022.The offline detection results showed that the PD of the A-phase branch 3 in the first test was twice that of the other branches,but in the subsequent tests,the value of the A-phase branch 3 dropped to the same level of the other branches.The value of branch 4 was higher in the last three tests,but there was no significant change.On the other hand,an analysis of the overall trend of online PD from 2016 to 2019 revealed that there were periods of temporary increase and stability,as well as periods of relatively low values.The increased PD pulse data was analyzed by using the software,and it was found that the original pulse data was incomplete,which led to deviations in the analysis of the cause.The analysis results indicate that the PD value of first generator remained within an acceptable range.Moreover,its performance has been stable over time.No corona phenomenon has been found on the surface of the stator bars.Therefore,the insulation performance of the stator winding is stable and no defects.