During operation of high voltage (HV) motors, different types of discharges, e.g. surface discharge, corona discharge and bar-to-bar discharge can occur at the same time, increasing the difficulty of partial discharge (PD) sources determination and PDs pattern identification. In this study, the end-winding of a 10 kV motor coil was artificially aged and the related PD was measured. The initiation and variation of different PDs under multi-factor stresses were studied. The localised fingerprints coexisting with multiple PDs were identified and analysed. The results confirm that the end-winding discharge process was significantly influenced by the experiment relative humidity (RH) and temperature. The bar-to-bar discharge was easily recognised at a lower voltage since the identification of bar-to-bar discharge pattern would be affected by the corona discharge pattern at a higher voltage. It is shown that it is more difficult for the corona discharge to be detected when RH exceeded 80%, while the surface discharge dominated at the higher RH. In addition, the PDs were more easily identified with the rise of the temperature. This study can provide a reference in PD identification test and be useful for the PD online monitoring of HV motors.

在高压（HV）电机运行期间，可能会同时发生不同类型的放电，例如表面放电，电晕放电和条对条放电，这增加了部分放电（PD）源确定和PD模式识别的难度。在这项研究中，对10 kV电机线圈的端部绕组进行了人工老化，并测量了相关的局部放电。研究了多因素胁迫下不同PDs的引发和变化。鉴定并分析了与多个PD共存的局部指纹。结果证实，绕组端部放电过程受实验相对湿度（RH）和温度的影响很大。由于在较高电压下电晕放电模式会影响到线性放电模式，因此在较低电压下很容易识别出线性放电。结果表明，当相对湿度超过80％时，很难检测到电晕放电，而在较高的相对湿度下，表面放电占主导。另外，随着温度的升高，PD更容易识别。该研究可为局部放电识别测试提供参考，对局部放电在线监测高压电机很有用。