PULSE MEASUREMENTS USING LED IN DIELECTRIC LIQUIDS UNDER IMPULSE VOLTAGES

Current pulses, in the form of partial discharges, are known to be pre cursors of electrical breakdown in dielectric liquids. The precise mea surement of these pulses is of great value for the understanding of th e breakdown mechanism. The measurement of current pulses under impulse voltage is very difficult when using conventional electrical measurem ent systems. To overcome this difficulty, a novel measuring system usi ng fiber optics and a light emitting diode (LED) has been developed. I n this paper, the improvements in time response and charge sensitivity of such a LED current-pulse measurement system are described. Using t his system and a high speed shadowgraph assembly under impulse conditi ons, the current pulse and the streamer initiation in dielectric liqui ds are measured simultaneously.