A sensor powered by pulsed light (for gas density of GIS)

High optical/electrical energy conversion efficiency was achieved in an optical power supply system which drives a sensor by the optical energy supplied through an optical fiber cable from a laser diode, succeeding in supplying electric power over a distance of 1 km. By matching the impedances of load and of a photodiode, while converting pulsed light into electrical signals with the photodiode and boosting with a transformer, a high optical/electrical energy conversion efficiency of 14.8% was obtained. This power supply method was applied to a sensor for measuring the gas density of extrahigh-voltage substation gas-insulated switchgear (GIS) which can display the merits of an optical-transmission sensor. The sensor section of the gas density sensor, consisting of a transistor temperature sensor and a semiconductor pressure sensor, could be driven by an optical input of 2.3 mW.<
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