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Dielectric-Recovery Characteristic of Power Arcs in Large Air Gaps

McCann, G. D. and Conner, J. E. and Ellis, H. M. (1950) Dielectric-Recovery Characteristic of Power Arcs in Large Air Gaps. Transactions of the American Institute of Electrical Engineers, 69 (1). pp. 616-625. ISSN 0096-3860.

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A satisfactory test technique has been developed for studying the rates of dielectric recovery of large air gaps and other types of power-system insulation. This permits the accurate control of the fault conditions so that all practical types of fault currents can be studied. These are: (1) very high magnitude short-duration surges typical of lightning currents; (2) currents of power-system frequencies; and (3) intermediate duration currents such as those which might result from high-frequency current zeros produced by natural system oscillations. Results are presented showing the rate of dielectric recovery of 3-, 6-, and 11-inch standard rod gaps for power frequency fault currents up to 700 amperes. Electrode cooling effects were found important at 3-inch gap spacings but not at six inches or above. The 11-inch gap data are proportionately higher than the 6-inch data indicating that the results can be extrapolated. The data show that for arcs of a few cycles actual duration has little effect on rate of recovery. A range of current magnitudes from 50 to 700 amperes causes only about a 2-to-1 variation in rate of recovery. For the normal ratios of transmission-line insulation level to operating voltage (about four to one) minimum delay times of from 0.025 second for 100-ampere faults to 0.05 second for 700 ampere faults are required before the recovery voltage reaches the magnitude of the normal applied voltage. Time intervals of 0.05 to 0.

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Additional Information:© 1950 AIEE. Paper 50-96, recommended by the AIEE Transmission and Distribution Committee and approved by the AIEE Technical Program Committee for presentation at the AIEE Winter General Meeting, New York, N. Y., January 30-February 3, 1950. Manuscript submitted November 2, 1949; made available for printing December 2, 1949.
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Official Citation:G. D. McCann, J. E. Conner and H. M. Ellis, "Dielectric-Recovery Characteristic of Power Arcs in Large Air Gaps," in Transactions of the American Institute of Electrical Engineers, vol. 69, no. 1, pp. 616-625, Jan. 1950. doi: 10.1109/T-AIEE.1950.5060195
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:80757
Deposited By: Kristin Buxton
Deposited On:24 Aug 2017 01:05
Last Modified:03 Oct 2019 18:34

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