关于水轮发电机整机交流阻抗无法判断转子绕组匝间短路问题的研究

通过对某电站2号水轮发电机与其他电站多台类似电机显极式1]转子绕组出现匝间短路的数据对比,发现个别磁极出现匝间短路的情形下,其整体交流阻抗未出现明显变化,进一步证实了其转子绕组整体交流阻抗试验,无法有效发现转子单个磁极是否存在匝间短路,检测的有效性、准确性较差。应采用测量单个磁极的交流阻抗判断转子绕组是否存在匝间短路更为有效,以避免故障被掩盖。

Incapability of Overall AC Impedance Test for Determination of Inter-turn Short Circuit of Rotor Windings

Based on the analysis of several inter-turn short circuit faults of rotor windings encountered in explicit pole hydro-turbine generator units,it is found that the inter-turn short circuit in one magnetic pole of the rotor windings cannot be effectively and accurately determined by the overall AC impedance test,as the overall AC impedance does not change significantly in case of inter-turn short circuit in individual poles.Thus,it is more effective to measure the AC impedance of individual poles to judge whether there is inter-turn short circuit in the rotor windings.