基于局部放电的水轮发电机定子绕组层间间隙放电的检测与分析  

Detection and analysis of interlayer gap discharge in hydrogenerator stator winding based on partial discharge

作　　者：杨增杰 赵显峰 张学明 李坚 刘剑明 孙永鑫 YANG Zengjie;ZHAO Xianfeng;ZHANG Xueming;LI Jian;LIU Jianming;SUN Yongxin(Maintenance Branch,Huaneng Lancang River Hydropower Inc.,Kunming 650000,China;Jinghong Hydropower Station,Huaneng Lancang River Hydropower Inc.,Jinghong 666100,China;National Engineering Research Center Hydropower Equipment,Harbin 150040,China)

机构地区：[1]华能澜沧江水电股份有限公司检修分公司,云南昆明650000 [2]华能澜沧江水电股份有限公司景洪水电厂,云南景洪666100 [3]哈动国家水力发电设备工程技术研究中心有限公司,黑龙江哈尔滨150040

出　　处：《绝缘材料》2024年第1期94-100,共7页Insulating Materials

基　　金：中国华能集团科技项目(HNKJ22-HF95)。

摘　　要：为提高绕组层间间隙放电故障诊断的可靠性,以水轮发电机定子绕组为试验对象,研究了通过局部放电诊断层间间隙放电时的影响因素。首先通过离线试验、在线试验、模拟试验方法获取绕组多放电源叠加时的层间间隙放电局放特征,然后通过线棒模拟电气传导衰减,结合发电机绕组结构、检测距离,分析检测距离对检测结果的影响。结果表明:绕组层间的间隙放电有独立特征,在其PRPD模式图中脉冲分布呈悬浮状且具有对称的正负极性,脉冲峰值位于45°和225°前后,两相中一相的正负极性脉冲峰值同时向右偏离45°和225°,另一相的正负极性脉冲峰值同时向左偏离45°和225°;当绕组结构不同时,放电间隙分布和汇流环长度也不同,由此造成的检测距离差异对局部放电信号幅值检测结果有较大影响,如果只考虑电气传导,检测距离每增大1 m,局部放电幅值平均衰减约10%,当只有距离较近的一相能检测到间隙放电时相间分析方法失效;即使绕组中同时存在多个放电源和间隙放电也可以通过间隙放电PRPD模式图的悬浮特征识别层间间隙放电;检测量程对局部放电模式识别有影响,当大量程全局图谱完整但局部模式相互重叠时无法识别具体故障,当小量程全局图谱不完整但局部模式图清晰时可识别具体故障。In order to improve the reliability of interlayer gap discharge faults diagnosis in winding,taking a hydrogenerator stator winding as the experimental object,the influencing factors of diagnosing interlayer gap discharge through partial discharge were studied.Firstly,the characteristics of interlayer gap discharge in winding under the superposition of multiple discharge sources were obtained through offline test,online test,and simulation test.Then,by simulating the electrical conduction attenuation of bar and combined with the generator winding structure and detection distance,the effect of detection distance on the detection results was analyzed.The results show that the winding interlayer gap discharge has independent characteristics,the pulse distribution is suspended in PRPD pattern and has symmetrical positive and negative polarities.The pulse peak values are located around 45°and 225°.In one phase,the positive and negative polarity pulse peak values simultaneously deviate to the right of 45°and 225°,while in the other phase,the positive and negative polarity pulse peak values simultaneously deviate to the left of 45°and 225°.When the winding structure is different,the distribution of discharge gaps and the length of lead ring are also different,resulting in significant differences in detection distance,which has great effect on the amplitude detection results of partial discharge signals.If only electrical conduction is considered,for every one meter increase in detection distance,the average attenuation of partial discharge amplitude is approximately 10%.When only one closer phase can detect gap discharge,the interphase analysis method fails.Even there are multiple discharge sources and gap discharge simultaneously in winding,the interlayer gap discharge can be identified through the suspended characteristics of gap discharge PRPD pattern.The detection range has an impact on the identification of partial discharge patterns.When the global spectra with large range is complete,while the local patterns

关 键 词：水轮发电机 层间间隙放电 PRPD 传播衰减 绕组结构 悬浮特征 

分 类 号：TM312[电气工程—电机]