What question did this study set out to answer?

To evaluate the impulse breakdown voltage characteristics of large sphere-plane and rod-plane gaps under varied impulse waveform risetimes.

January 1, 1972Proceedings of the Institution of Electrical Engineers

Impulse breakdown of large sphere-plane gaps

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Authors

JHJ.K. HepworthE.ON (United Kingdom)RKR C KleweWorcestershire Royal Hospital BTB.A. TozerLaser 2000 (United Kingdom)

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Implication

Experimental study demonstrates reduced breakdown strength under slow impulse waveforms in large air gaps, indicating peak field limits prevent insulation failure.

Key Points

To evaluate the impulse breakdown voltage characteristics of large sphere-plane and rod-plane gaps under varied impulse waveform risetimes.
Tested air gap spacings ranging from 0.75 m to 3 m utilizing sphere radii of 125 mm to 375 mm and a 12.5 mm square-cut rod.
Applied positive- and negative-polarity impulse waveforms with fast risetimes of 1–2 μs and slow risetimes of 80–130 μs.
Demonstrated that low breakdown strength during slow positive impulses results from high anode peak electric fields initiating early impulse-corona.
Identified that maintaining peak electric fields below 4.1 MV/m significantly increases gap insulation strength and eliminates the U-curve phenomenon.
Formulated an empirical scaling law for spheres with radii exceeding 10% of the gap distance: Emean = 3.75 - 0.81 Epeak MV/m.

Cite This Study

Hepworth et al. (1972) studied this question.

synapsesocial.com/papers/6a904eae4aebf474cb3419a1 https://doi.org/10.1049/piee.1972.0355

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Implication

Experimental study demonstrates reduced breakdown strength under slow impulse waveforms in large air gaps, indicating peak field limits prevent insulation failure.

Impulse breakdown of large sphere-plane gaps

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Implication

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Cite This Study

Impulse breakdown of large sphere-plane gaps

Discussion

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Implication

Key Points

Cite This Study

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