Special design and arrangements of UHV AC conductors and subconductors taking reduction of environmental impact into consideration

摘要

To take countermeasures against wind noise from overhead transmission lines, a method of fitting an aluminum rod around each conductor - the so-called Spiral Rods application - has been adopted so far. A 1100 kV transmission line uses as many as 8-bundle conductors per phase, and the number of spiral rods per subconductor required to counteract corona audible noise becomes twice as many as those for the transmission lines rated at 550 kV or less. Therefore the workload for the installation of spiral rods is increased. Moreover, the majority of the routes of these transmission lines cross populated area in both hilly and flat terrains, making it mandatory to provide measures against wind noise. The authors have developed low-noise conductors for 1100 kV transmission lines with improved performance in the reduction of wind-generated hissing sounds and corona-generated hums. The geometry of the surface protrusions has been designed to minimize both wind and corona audible noises, and the newly developed conductor has been installed on 1100 kV transmission lines and been in use successfully.