基于励磁磁动势差值的汽轮发电机转子匝间短路在线识别方法

Online inter-turn short circuit identification based on exciting MMF difference for rotor winding of steam-turbine-generator

汽轮发电机转子绕组发生匝间短路时会引起励磁磁动势缺失,但在励磁系统恒压闭环调节作用下,励磁电流将增大以补偿励磁磁动势缺额。分析了汽轮发电机转子匝间短路故障时励磁磁动势变化特征,以故障后由励磁电流计算得的"视在"励磁磁动势大于发电机当前工况下所需的励磁磁动势为理论依据,提出了基于励磁磁动势差值的转子匝间短路在线识别方法。试验结果表明了采用所提方法可有效在线识别转子匝间短路故障。

The rotor-winding inter-turn short circuit of steam-turbine-generator may cause the loss of exciting MMF（Magnetic Motive Force）,which will be compensated by the increased exciting current under the constantvoltage closed-loop control. The variation characteristics of exciting MMF during the inter-turn short circuit fault are analyzed and a method of online inter-turn short circuit identification based on exciting MMF difference for the rotor winding is proposed based on the theoretical analysis that the apparent exciting MMF calculated according to the exciting current during the short circuit fault is larger than the exciting MMF needed by the generator at that moment. The test results show that,with the proposed method,the rotor-winding inter-turn short circuit can be effectively online identified.