Improved lightning arrestor protection results, final results. Final report
- Univ. of Florida, Gainesville, FL (United States). Dept. of Electrical and Computer Engineering
This report is primarily based on triggered lightning experiments conducted by the University of Florida (UF) at the Camp Blanding facility from 1993 to 1998. In 1995 and 1996, MOV arresters were installed on the system for twelve artificially-initiated lightning flashes striking the system`s overhead line directly. Ten of these cases were strikes to the phase conductor of the line, and two, in 1996, were strikes to the neutral. Additionally, in 1995, nearby natural lightning forced current into the system`s neutrals from each, and in 1996, natural lightning hit the phase conductor of the line, both occurring while the system was equipped with arresters. Simultaneous arrester discharge current and voltage waveshapes were obtained for nine of the triggered lightning flashes, including the two strikes to the neutral in 1996, but for neither of the two natural lightning. Arrester voltages, on the other hand, are available for eleven triggered flashes and one natural lightning. The energy absorption by an arrester as a function of time can be calculated, when the simultaneous currents and voltages are available, as the time integral of the current-voltage product. The division of lightning current injected into the neutral of the distribution line among multiple pole grounds is analyzed. The observed difference in waveshapes of currents in different grounds suggests that grounding impedances are frequency dependent, non-linear, or both. The earthing system of a simulated house was struck by lightning for three different configurations. The division of lightning current injected into the simulated house earth system under these three configurations is analyzed. The effects of the presence or absence of SPDs and the variation of the dc grounding resistance of the simulated house earthing system are examined. The change of the dc grounding resistance of a typical ground rod as a function of time and weather conditions is studied.
- Research Organization:
- Electric Power Research Inst., Palo Alto, CA (United States); Univ. of Florida, Dept. of Electrical and Computer Engineering, Gainesville, FL (United States)
- Sponsoring Organization:
- Electric Power Research Inst., Palo Alto, CA (United States)
- OSTI ID:
- 355068
- Report Number(s):
- EPRI-TR--109670-R1
- Country of Publication:
- United States
- Language:
- English
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