Electric discharge detection and localization using a distributed optical fiber vibration sensor

• Published in: Optical fiber technology Vol. 58; p. 102266
• Main Authors: da Costa, Igor Brutkowski Vieira, Weber, Guilherme Heim, Gomes, Danilo Fernandes, Galvão, José Rodolfo, da Silva, Marco J., Pipa, Daniel R., Ozcáriz, Aritz, Zamarreño, Carlos R., Martelli, Cicero, Cardozo da Silva, Jean Carlos
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-09-2020
• Subjects: Distributed sensor; Optical fiber sensor; Partial discharge; Sagnac interferometry; Sagnac interferometry; Partial discharge; Distributed sensor; Optical fiber sensor
• ISSN: 1068-5200; 1095-9912
• DOI: 10.1016/j.yofte.2020.102266

•Sagnac interferometry for electric discharges detection.•The system is less complex when compared to DAS systems.•Sagnac interferometer to detect and locate electric discharges is evaluated.•High availability and simplicity of low coherence optical sources make it feasible.
Partial discharges are a type of electric discharge that cause localized breakdowns in a small portion of an insulating material without forming a complete rupture. In high power electric machines as well as in transmission lines, partial discharges are caused by the degradation and/or the presence of defects in the insulation. The damage caused by the partial discharges can be either thermal, mechanical or chemical and can cause progressive deterioration of the insulation and lead to catastrophic failure causing serious safety risks. In this work a Distributed Optical Fiber Sensor System (DOFS) for vibration measurements based on Sagnac interferometry is proposed. This system uses acoustic wave emission phenomena to detect and locate electric discharges in electric machines and insulated electrical cables. Two experiments were carried out evaluating the performance of the system. Electric discharges were measured firstly over a conductive board with an attached 10 m long flat-coiled optical fiber sensor and secondly, over a 1.20 m long electrical cable with an optical fiber sensor longitudinally attached to it. Results demonstrate that due to the high sensitivity of the system it is possible to detect partial discharges in both proposed experiments. This effect is observed even with a theoretical fiber optical sensing spatial resolution of approximately 50 m.