一起330MW汽轮发电机转子绕组短路故障分析及处理

Analysis and treatment of a 330MW turbine-generator rotor winding short circuit fault

针对一起300MW汽轮发电机因转子绕组包间短路导致转子一点接地故障且大轴严重磁化,从而无法起机并网的事故进行分析,认为转子汽端第7、8套绕组端部铜线在长期运行过程中产生蠕变塑性变形,致使包间绝缘间隙变小,在起机过程中绕组铜线发热膨胀导致第7、8套绕组突发包间短路故障是此次事故发生的根本原因,最后提出相应的检修处理建议并对转子大轴进行现场退磁处理。

This paper analyzes an accident of a 300MW steam turbine generator that could not be started and connected to the grid due to a one-point grounding fault of the rotor and serious magnetization of the large shaft caused by a short circuit between the rotor windings.According to the analysis,creep plastic deformation occurred in the rotor steam end results in the insulation gap between the packages smaller.The copper wire of the coil is heated and expanded,which causes a sudden short-circuit fault between the 7 and 8 sets of winding during starting.Finally,corresponding improvement suggestions are proposed and the rotor shaft is demagnetized.