四川大学学报（自然科学版）2025，Vol.62Issue(5)：1025-1033,9.DOI:10.19907/j.0490-6756.250132
基于电磁测试的水轮发电机局部放电监测新方法
Novel partial discharge monitoring method based on electromagnetic testing for hydrogenerators
摘要
Abstract
Partial discharge(PD)monitoring is a well-established technique for diagnosing insulation faults in generator stator windings.However,traditional pulse current monitoring methods,which rely on capaci-tive sensors to capture PD signals,face several limitations,including high retrofitting and installation costs and heavy dependence on imported critical components.Additionally,the complex electromagnetic(EM)en-vironment during hydrogenerator operation can significantly compromise the accuracy of EM-based diagnostic results.Engineering experience shows that the frequency-domain characteristics of background electromag-netic interference(EMI)and those of typical PD faults remain relatively stable over time.Consequently,se-lecting non-overlapping frequency bands for EM-based measurements can effectively reduce the impact of background noise.Field measurements on in-service hydrogenerators further validate the practicality and accu-racy of EM-based PD monitoring.This study introduces a novel non-contact PD monitoring method specifi-cally designed for hydrogenerators.The proposed approach explicitly accounts for the complex EM environ-ment in hydropower stations and the EM characteristics of typical PD faults that influence measurement accu-racy.The method operates by capturing characteristic EM pulses generated by rapid charge migration during PD events,enabling accurate non-contact PD detection.An analysis of background EMI in a hydropower sta-tion using this method revealed consistent operational interference levels in SF165-66 hydrogenerators,typi-cally ranging from-75 dBm to-80 dBm(PdBm=10×lg(PW×1000),30 dBm=1 W).Prominent interfer-ence peaks were observed near 1.76 GHz,2.55 GHz,and 3.40 GHz.During in situ PD measurements on an operational SF165-66 hydrogenerator,broadband PD signals in the 0.5 GHz to 1.0 GHz range were suc-cessfully detected.Comparative analysis with simulated PD sources—based on wear defects in the low-resistance anti-corona coating at winding ends—confirmed that the method accurately captures PD-related sig-nals.This work marks the first successful implementation of non-contact,non-destructive PD testing for hy-drogenerators under normal operating conditions.It directly addresses key limitations of traditional pulse cur-rent methods,including their high cost,reliance on imported hardware,and intrusive installation processes.The proposed method offers a lightweight and flexible deployment strategy suitable for retrofitting PD moni-toring systems in existing hydropower stations and for applications in small-to-medium hydropower plants.The non-contact EM-based method allows for flexible installation without the need for invasive modifications.Installation can be completed within 7～10 days during minor maintenance outages.Moreover,it eliminates risks associated with traditional methods,such as introducing new insulation failures from drilling stator bars for high-voltage sensor placement,and reduces both construction costs and implementation time.These ad-vantages make the method especially suitable for retrofitting PD monitoring in operational hydropower sta-tions and for lightweight,scalable deployments.关键词
水轮发电机/局部放电监测/非接触式/电磁法Key words
Hydrogenerator/Partial discharge monitoring/Non-contact/Electromagnetic method分类
信息技术与安全科学引用本文复制引用
王海平,王国丽,杨东,宋坤隆,郭德明,刘云平,黄泽,王骥千..基于电磁测试的水轮发电机局部放电监测新方法[J].四川大学学报（自然科学版）,2025,62(5):1025-1033,9.基金项目
国家自然科学基金企业创新发展联合基金重点项目(U24B20108) （U24B20108）
