某核电汽轮机轴瓦电腐蚀问题分析和处理  

Analysis and Treatment with Bearing Electrical Pitting for a Nuclear Turbine

作　　者：王保田 WANG Bao-tian(Sanmen Nuclear Power Plant Co.,Ltd.)

机构地区：[1]三门核电有限公司,浙江台州317112

出　　处：《电站系统工程》2025年第2期59-62,65,共5页Power System Engineering

摘　　要：某核电站#1机组汽轮机在停机后启动冲转过程中,#2轴承温度高造成碾瓦,通过故障树分析法确定原因为发电机大轴接地不良,机组运行期间轴电压升高发生电腐蚀致轴瓦面凹凸不平;在低转速油膜较薄工况下,蚀坑凸起处与轴颈摩擦致轴承发热碾瓦。大轴接地不良的原因为发电机转子接地铜编织带与轴颈表面接触差,轴电压测量碳刷和铜编织带安装在同一圆周滑道上,剥落的碳粉和碎铜屑进一步加剧铜编织带接地不良。通过增加接地碳刷、错开碳刷和铜编织带滑动轨道、加强大轴接地装置的监测和预维等措施杜绝轴电压超标。HP turbine No.2 bearing metal temperature rose and babbitt wiping occurred at low rotating speed after rolling turbine for a nuclear power plant unit 1.Based on Fault Tree Analysis method,the root cause was poor generator shaft grounding,which result in the shaft voltage rising and electrical pitting(EP) on the loaded surface of the journal bearing at normal operation.Following the oil film thinness at low speed stage,EP disrupted the hydrodynamic film and increased surface roughness that generated babbitt overheat damage.The reason for the poor grounding was the undesirable rough surface contact between the generator rotor with the copper braid earth belt.The carbon brush for shaft voltage measurement and the copper braid earth belt were installed on the same circumferential slide,which made the peeling carbon powder and copper chips further aggravated the bad grounding of the copper braid earth belt.By adding one additional grounding carbon brush,staggered the sliding track of carbon brush and copper braid earth belt,strengthening the monitor and prevention maintenance of shaft grounding device to prevent the shaft voltage exceeding the standard.

关 键 词：轴瓦 电腐蚀 碾瓦 轴电压 分析处理 

分 类 号：TK393[动力工程及工程热物理—热能工程]