Dielectric-Recovery Characteristic of Power Arcs in Large Air Gaps
- Creators
- McCann, G. D.
- Conner, J. E.
- Ellis, H. M.
Abstract
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.
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.Attached Files
Published - 05060195.pdf
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Additional details
- Eprint ID
- 80757
- Resolver ID
- CaltechAUTHORS:20170823-174326006
- Created
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2017-08-24Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field