Summary
Partial discharges (PD) in high-voltage (HV) bushings are a critical early indicator of insulation degradation and can lead to catastrophic transformer failures if undetected. Conventional electrical PD measurements (IEC 60270) are often challenged in in-service substations by electromagnetic interference (EMI), limited localization capability, and restricted access to test taps. Acoustic emission (AE) techniques provide a complementary approach; however, conventional piezoelectric sensors are limited by EMI susceptibility, the need for powered electronics, and reduced flexibility for multiplexed monitoring. This paper presents an industrial evaluation of fiber optic acoustic emission (FOAE) sensing for PD detection and monitoring in HV bushings, using point sensors rather than distributed acoustic sensing (DAS).
Read more Read lessA controlled experiment was conducted on two full-scale bushings, one faulty and one reference, equipped with six FOAE sensors in multiple configurations, alongside simultaneous electrical PD measurements via the bushing test tap.
The results demonstrate that FOAE sensors reliably detect PD activity at inception voltages of approximately 80–85 kV, corresponding to apparent charge levels around 1 nC. The highest sensitivity was consistently achieved with sensors mounted at the base of the bushing, indicating that even a single base-mounted FOAE sensor can provide effective PD monitoring in similar geometries. The passive and dielectric nature of the sensors ensures safe operation without influencing the electric field or normal bushing performance. Remaining challenges include acoustic attenuation over long bushing lengths, discrimination between internal and external PD sources, and sensitivity dependence on defect type and coupling conditions. Future work will focus on advanced signal processing, improved localization strategies, and validation under controlled and operational conditions.
Additional informations
| Publication type | Session Materials |
|---|---|
| Reference | D1_10308_2026 |
| Publication year | |
| Publisher | CIGRE |
| Country | Netherlands, The |
| Study committees | |
| File size | 1 MB |
| Price for non member | 30 € |
| Price for member | 30 € |
Authors
HASHEMI-DEZAKI Hamed - Optics11; ZADEH Aydin - Optics11; VOETEN Stefan - SGB-SMIT Group; ZHAO Weichuan - Optics11
Keywords
Fiber optic acoustic emission (FOAE) sensing technology, High-voltage Bushing, Partial discharge (PD), Online PD monitoring, PD localization, Power transformer
