Air gap sparkover and gap factors: Analysis of published data. Final report
- High Voltage Transmission Research Center, Lenox, MA (United States)
This report is an account of a literature search on air gap sparkover which was conducted as part of the Live Working 2000 project. The objective of this literature search was to locate and analyze published data on sparkover of air gaps which are relevant to live working. The sparkover data form the basis for determination of gap factors for live working situations. Data dating back to 1930`s were located in published papers and reports, extracted and analyzed for a variety of air gaps, including: rod-to-plane, rod-to-rod, sphere-to-plane, bundle-to-plane, hoop-to-plane, bundle-to-tower window, bundle-to-tower outside phase, and worker-to-tower air gap. The rod-to-plane air gap has been analyzed extensively in the literature, and several accurate empirical formulae have been developed to calculate the 50% sparkover voltage of the gap when subjected to transient overvoltages with the critical wave shape. The terms, such as gap factor, transient overvoltage (TOV), critical wave shape, and other relevant terms, are defined in this report for completeness. The CRIEPI formula is used as the reference in this report, since this formula has been adopted by several technical organizations (IEC, IEEE). Comparisons are also made with the second popular formula, the Gallet formula. All sparkover data obtained from the literature are presented in tables and graphs. In addition, where applicable and available, data for the critical wave shape are identified and placed in separate tables for ready reference. The calculated gap factors are based on the CRIEPI formula. Detailed comparisons of the CRIEPI and the Gallet formulae allow easy determination of the gap factors based on the Gallet formula, should one desire to compute these numbers. The calculated gap factors are summarized in tables and compared with the gap factor values tentatively suggested for use by IEC TC 78 WG 10.
- Research Organization:
- Electric Power Research Inst., Palo Alto, CA (United States); Electric Power Research Inst., Lenox, MA (United States). High Voltage Transmission Research Center
- Sponsoring Organization:
- Electric Power Research Inst., Palo Alto, CA (United States)
- OSTI ID:
- 10107034
- Report Number(s):
- EPRI-TR-104437; ON: UN95005447; TRN: 95:000861
- Resource Relation:
- Other Information: PBD: Dec 1994
- Country of Publication:
- United States
- Language:
- English
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