Sensitive optical detection of Partial Discharges with fluorescent fibers

Summary

The optical detection of partial discharges (PD) provides the unmatched benefit of being absolute immune to practically any type of electromagnetic interference, besides light itself. Power apparatus with encapsulated high voltage insulation, like GIS, oil-paper insulated power transformers or terminations of HV power cables exclude external light by design. The occurrence of light inside such equipment would clearly indicate severe problems with the insulation system. To detect such light from defects, the insulation material must be transparent to permit light to propagate to a light sensor. To achieve suited optical detection sensitivity, the spectral characteristics of the PD source, the optical transmission through transparent material, the light sensor and the optical-electrical converter were carefully investigated. This paper describes the design, properties and application of the complete optical measurement chain including fluorescent optical fibers (FOF) as distributed light sensors and avalanche photo diodes (APD) to convert PD light intensity into electrical signals of proportional magnitude. The electrical signals can then be detected with standard PD measuring systems. Fluorescence dyes for FOF design were chosen to sensitively absorb the PD light and to emit light of longer wavelength, better suited for silicium-based optical-electrical converters with a sensitivity maximum at approx. 800nm and so maximizing overall quantum efficiency.

Additional informations

Authors

Phung Bao Toan, Potivejkul Siriwat, Patthanadech Norasage, Sato Masahiro, ilhan Suat, Guo Peiqi, Ozdemir Aydogan, Zhong Lipeng, Nourirad Ghasem