Sensitive optical detection of Partial Discharges with fluorescent fibers

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…