Current pulse measurement system using LED in dielectric liquids under impulse voltage conditions

Yamazawa, K.; Uemura, M.; Yamashita, H.; Forster, E. O.

doi:10.1109/icdl.1993.593966

Cited by 5 publications

(1 citation statement)

References 7 publications

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“…The maximum framing speed of the ICC was 50 ns/Frame. Partial discharge (PD) current pulses were measured simultaneously using a LED current pulse measurement system (LCPMS) which has a minimum charge sensitivity of 5.5 pC and temporal resolution of 3 ns [4]. In case of using metal cryostat under impulse conditions, it is difficult to make precise measurements of the current pulses due to the large stray capacity of the cell.…”

Section: Experimental Apparatusmentioning

confidence: 99%

Prebreakdown phenomena in cryogenic liquids

Yamazawa

Yamashita

Forster

Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)

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Streamer initiation and propagation processes were observed in liquid nitrogen under non-uniform field. A high magnification (63.5x), high speed (up to 50 ns/Frame) shadowgraph system was employed for the optical measurements. Under impulse voltage conditions, there were two types of negative streamer; one was a slow (10-100 m/s) bush-like streamer and the other a filamentary one which was faster (100-500 m/s) and grew straight or sometimes winding towards the opposite electrode. In both cases, the initial structure of the streamer appeared to he a filament. In conjunction with the optical study, current pulses were also measured simultaneously using a LED current pulse measurement system. The onset of the current pulse occurred prior to the streamer inception for both types of streamers but their frequency and amplitude were quite different.

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Section: Experimental Apparatusmentioning

confidence: 99%

Prebreakdown phenomena in cryogenic liquids

Yamazawa

Yamashita

Forster

Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)

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Observation of cathode streamer initiation in dielectric liquids under high magnification

Yamazawa

Okumura

Uemura

et al.

Proceedings of IEEE Conference on Electrical Insulation and Dielectric Phenomena - (CEIDP '93)

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The initiation process of cathode streamer was observed in cyclohexane under non-uniform field. An impulse voltage was applied to a tungsten needle of 0.5 pn radius. The streamer growth was photographed using a high magnification, high speed shadowgraph system. The streamer initiation voltage was determined to be -5.18 kV. The initial streamer structure was filamentary. Within 100 ns of inception it changed to a bush-like structure which increased with increasing voltage until a secondary stem appeared and the process appeared to repeat itself. After their expansion process stopped they were noted to break up into small bubbles. Partial discharges (PD) were also measured in conjunction with this study using a LED current measurement system. The relation between PD and streamer growth is also discussed.

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