Measurement of electrical conductor drag coefficients in a free-air wind tunnel
- Sverdrup Technology, Inc., Haslet, TX (United States)
Significant differences between conductor drag coefficients generated in wind tunnel tests and conductor drag coefficients derived from full-scale field load measurements have been reported. Most of these full-scale wind loading experiments measure swing angles and insulator forces on long conductor spans in the open air while wind tunnel tests measure drag force directly on short conductor segments under laboratory conditions. Difficulties arise when attempting to identify the causes of discrepancies in drag coefficients derived from these two different types of testing. The first phase of this research was to build a ``free-air wind tunnel`` to measure conductor drag coefficients in the open air with a wind-tunnel like test setup. This experiment was conducted to see if the same drag coefficients could be obtained by measuring conductor loads in open air as were measured in wind tunnels for similar conductor models. The tests were performed on one smooth cylinder and three conductor models with similar surface roughness. A test frame with necessary instrumentation attached was installed on a platform 20 meters above the ground. The existing wind tunnel drag coefficient data were compared with the drag coefficient data recorded at the TLMRC EPRI`s Transmission Line Mechanical Research Center (TLMRC). The results of this study show that the drag coefficients from the ``free-air wind tunnel`` are comparable to those obtained from quality wind tunnel tests in the wind velocity range that the field data were recorded. This implies that wind tunnel drag data are sufficient to determine the drag forces on a short segment of conductor in open air. Other experiments, are still necessary to resolve the discrepancies between the wind tunnel data and existing field data. This report summarizes the results from the first phase of research.
- Research Organization:
- Electric Power Research Inst., Palo Alto, CA (United States); Sverdrup Technology, Inc., Haslet, TX (United States)
- Sponsoring Organization:
- Electric Power Research Inst., Palo Alto, CA (United States)
- OSTI ID:
- 10113014
- Report Number(s):
- EPRI-TR-100672; ON: UN93004786
- Resource Relation:
- Other Information: PBD: Nov 1992
- Country of Publication:
- United States
- Language:
- English
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