大型发电机操作过电压的安全预测分析新方法

随着远距离输电线路电压等级的提高,大型电站中的操作过电压威胁着大型发电机的绝缘安全.针对大型发电机操作冲击过电压问题,结合场路综合分析计算,提出了大型发电机绝缘安全预测分析方法,并重点研究了大型发电机绝缘安全状态的特征量模式和绝缘安全的评估模型.通过研究大型电站中的操作过电压冲击波在发电机定子绕组绝缘介质中暂态电场的实时分布状态,在线分析发电机的绝缘工作状况,搜索发电机内部可能突发绝缘事故的区域,锁定可能发生绝缘事故的故障点,预测发电机组的绝缘安全状态,以便对大型发电机进行预防性保护与预知性维护工作.

A NEW METHOD FOR ONLINE SAFETY FORECAST ANALYSIS OF LARGE GENERATORS UNDER SWITCHING OVERVOLTAGE

With the increment of working voltage for the long-distance transmission line, the switching overvoltage in large power stations is threatening the insulation safety of large generators. For large generators stricken by the switching overvoltage, based on the field-circuit analysis and calculation, a new method for on-line forecast and analysis of the insulation safety of large generators is presented in this paper, and the character model and the assessment model for predicting insulation safety of large generator units stricken by the surge overvoltage are approached. The transient field distribution and the insulation condition in the stator winding insulator stricken by the switching overvoltage are studied and analyzed on line. At the same time, some insulation fault point and domain in generators can be predicted and even detected successfully so that the preventive protection and maintenance can be supplied to the large generators. Finally, a simulation example for forecasting the insulation safety of the large generator is given.