Study of television interference by small wind turbines. Final subcontract report
Electromagnetic interference to television reception caused by small wind turbines (generating about 5 kW of power) has been studied by carrying out measurements using 1/8th-scale models of small windmills in conjunction with a microwave TV system inside an anechoic chamber. Two- and three-bladed windmills with metallized and wooden blades rectangular and trapezoidal in shape were investigated. The locally available TV Channel 9 signal was received and, after up-converting its center frequency to 4.0 GHz, was used as the rf source of the microwave TV system. The television interference (TVI) results were extrapolated to give the TVI effects of the corresponding full-scale windmills at the commercial TV Channel frequencies. Generally, it was found that the two- and three-bladed machines produced similar TVI effects, the metallized blades producing stronger interference than the wooden blades. Extrapolation of the results obtained indicate that, even at the highest TV frequency, the significant TVI effects (video distortion) produced by small wind turbines will not extend out to a distance larger than about 2.5 times the rotor diameter. At lower TV frequenies (or Channel numbers) the distance will be correspondingly smaller. Within this distance, the observed effects will generally be small to negligible over most of the region except possibly in the forward interference direction.
- Research Organization:
- Michigan Univ., Ann Arbor (USA). Radiation Lab.
- DOE Contract Number:
- AC02-77CH00178
- OSTI ID:
- 6314552
- Report Number(s):
- SERI/STR-215-1880; ON: DE83011342
- Country of Publication:
- United States
- Language:
- English
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