摘要
为了有效评估大电机主绝缘的剩余寿命,对大量已运行 16、18 和 23 年的 300MW 发电机定子线棒进行统计最小波速 Vmin和统计平均波速 Vav的超声波波速测量试验,以及介质损耗角增量?tanδ、电容变化率?C/C0、最大放电量 qmax、平均放电量 qmean等电气测量试验,用线性回归分析对比研究了超声参数和电气参数与运行年数 y?的相关性。结果表明,Vmin 和 Vav与 y?密切相关,?tanδ、qmax和 qmean 与 y?相关性较弱,?C/C0与 y?没有相关性,超声参数比电气参数能更准确评估绝缘状态;分别建立了 Vmin和 Vav与 y?的二阶和三阶线性函数数学模型,提出了最可靠运行年数和置信度为95%的可靠运行年数的预测方法。
To assess the remaining life of large generator stator insulation effectually, lots of stator bars from three 300MW generators, which had been in-service for 16, 18 and 23 year periods respectively, were tested to diagnose the insulation condition. The measured parameters included statistical minimum ultrasonic velocity Vmin, statistical average ultrasonic velocity Vav, dissipation factor tip-up ?tanδ, change of capacitance ?C/C0, maximum discharge magnitude qmax and mean discharge magnitude qmean. With linear regression analysis A compared investigation of the correlation between Vmin, Vav and time in service y?was compared with that between ?tanδ, ?C/C0, qmax, qmean and y? respectively. The results showed that a significant correlation was evinced between Vmin, Vav and y?, that a most slight correlation between ?tanδ、qmax, qmean and y?, and that no definite correlation between ?C/C0 and y?. Vmin and Vav were of more accuracy than ?tanδ、qmax, qmean and ?C/C0 to assess stator insulation. A second-order and a third-order mathematic models were built to describe the relationships of Vmin, Vav with y?respectively. Based on the two models, predicted methods were proposed to assess the most reliable and the 95% reliable remaining life of stator insulation respectively.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2005年第4期76-82,共7页
Proceedings of the CSEE
基金
国家自然科学重点基金项目(59837260)
电力设备电气绝缘国家重点实验室开发课题基金。~~
