USA-USSR Investigation of 1200-kV Tower Insulation

Young, F.S.; Schneider, H.; Gutman, Y. M.; Tikhodeyev, N. N.

doi:10.1109/tpas.1980.319681

Cited by 8 publications

(1 citation statement)

References 4 publications

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“…Air gap discharges exhibit different characteristics under different impulse voltage waveforms. For example, the experimental results show that 50% breakdown voltage shows a certain U-shaped curve with the increasing front time under the same gap, and there exists a critical front time that minimises the breakdown voltage [23]. Based on three different voltage rise rates under a 1 m discharge gap, Cui discovered that the expansion rate of the discharge channel increased with the increasing voltage rise rate [24].…”

Section: Introductionmentioning

confidence: 99%

Discharge characteristics of leader inception and development under 10 m long air gap—experimental observation and simulation results

et al. 2022

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The physical mechanism of leader formation and development is not well understood. In this study, we present experimental and simulation results obtained with a 10 m long air gap discharge. A 10 m outdoor discharge experiment is carried out to obtain the current, voltage, and optical image during the leader discharge process. Four different impulse voltages were applied to the rod‐plane gap. The measured current is used as an input for a plasma model, then the temperature and electric field could be calculated. The simulation results show that the temperature of the streamer stem during the dark period may exceed 2000 K. In addition, the critical charge required for leader initiation can be as low as 0.27 μC for a 10 m air gap. The channel temperature is relatively stable in the process of leader development, which is maintained at about 4500 K. The electron density is about 0.5–3 × 1020 m−3, and the discharge channel conductivity fluctuates in the range of 1–10 S/m for the leader current between 1 and 2 A. A long dark period is tended to be associated with a higher injected charge by the first streamer. It is inferred that the voltage increments during the dark period play an important role in promoting streamer‐to‐leader transition, except for temperature and the injected charge.

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Section: Introductionmentioning

confidence: 99%

Discharge characteristics of leader inception and development under 10 m long air gap—experimental observation and simulation results

et al. 2022

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Estimation of switching surge flashover rate of 1200-kV UHVAC transmission line considering switching overvoltage waveshape

Annadi

Patsa

2020

Electr Eng

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The dynamic expansion of leader discharge channels under positive voltage impulse with different rise times in long air gap: Experimental observation and simulation results

Cui

Zhuang

Zhou

et al. 2019

Journal of Applied Physics

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In this paper, we observe the dynamic expansion process of positive leader channels under impulses with different rise times in a 1-m air gap using a Mach-Zehnder interferometry and a high-speed video camera. The thermal parameters describing the leader channel under a lightning and switching impulse are obtained through an analysis of interference fringes. The influences of different voltage waveforms on the dynamic expansion of leader channels are obtained. Firstly, the expansion rates of the channel radius are higher for shorter rise times. The average expansion rates are 72.30 ± 9.54, 28.09 ± 5.05, and 14.38 ± 3.02 m/s for the rise times of 1.2, 40, and 100 μs and the crest value of 425 kV for a 0.5-cm-diameter cone electrode; moreover, the temperatures at the centre of the leader channels are 5000–7000 K, 4000–6000 K, and 3000–4500 K, respectively. Secondly, the high-temperature region is larger for the shorter rise times. A numerical model was used to study the expansion of the leader channels, and the simulation results for the leader channel diameters showed good consistency with the experimental measurements. The continuous energy injection results in an over-pressure process in the leader channels and ultimately in their expansion. For a 1.2/50 μs waveform, the vibrational-translational relaxation (QVT) and the thermal dissociation (QD), which dominate the energy flow, are about one order of magnitude greater than that in a 100/2500 μs waveform. The convection loss and the ionization mechanism during the expansion process are also discussed.

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USA-USSR Investigation of 1200-kV Tower Insulation

Cited by 8 publications

References 4 publications

Discharge characteristics of leader inception and development under 10 m long air gap—experimental observation and simulation results

Discharge characteristics of leader inception and development under 10 m long air gap—experimental observation and simulation results

Estimation of switching surge flashover rate of 1200-kV UHVAC transmission line considering switching overvoltage waveshape

The dynamic expansion of leader discharge channels under positive voltage impulse with different rise times in long air gap: Experimental observation and simulation results

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