Characteristics of a Power Line Used as a VLF Antenna.

Abstract

The 100-kW transportable very low frequency transmitter system was used at Kafjord, Norway, for transmissions to the SCATHA and GEOS spacecraft. A 22-kV, 10.6-km long transmission line was used as an antenna. Modifications were made in the line to reduce telephone interference. Components were designed and installed to reduce the resonant frequency and increase the antenna current. The final practical operating current was 45 A at 1280 Hz. This resulted in power dissipation of 72 kW and an estimated radiated power of 0.17 to 0.79 W. BACKGROUND Attention in the Space Science community has recently been directed toward possible effects of powerline harmonic radiation on the earth's radiation belts [Helliwell et al., 1975; Park and Helliwell, 1978; Thorne and Tsurutani, 1979]. The members of the GEOS S-300 experiment scientific board proposed using power transmission lines for antennas in a program to transmit ELF signals to the GEOS satellite. Since The Aerospace Corporation also provided a VLF receiver for the P78-2 (SCATHA) satellite, this provided a unique opportunity to study power line radiation, wave-particle interactions and whistler-mode propagation in the outer magnetosphere. The measurements reported here were undertaken to understand the technical aspects of ELF/VLF radiation from an actual power line over a ground whose effective conductivity is a function of frequency. A 60-kV line was made available for tests at Andoya, Norway. Impedance measurements indicated that the line would be satisfactory as an antenna, however, local residents experienced troubles with appliances, which were being serviced temporarily with a 22-kV backup line. A 60-kV line, which did not require customers to receive service from an inferior line, was located in Konstadbotn, Norway, and preliminary transmissions were made by using the 100-kW TVLF transmitter [Koons and Dazey, 1974] running at currents as high as 50 amperes. Severe telephone interference was experienced. This was attributed to the fact that the line ran within a few hundred meters of a fjord, and most of the telephone Copyright ¸ 1982 by the American Geophysical Union. subscribers had residences between the line and the fjord. A third line was located in a remote part of Norway about 300 km from Tromso near the town of Kafjord. The line was approximately 15 km long. There were a few telephone subscribers near the Kafjord end of the line. Low-level tests indicated serious telephone interference in the nearby residences. Since the residences were all close to the transmitter end of the line, a test was made with the first 3.6 km of the line DAZEY AND KOONS

Dominant factors of electromagnetic interference problems of asymmetrical and equi-distance differential-paired lines

“…By advancement of electronics information and communication technologies, computerization, and internationalization of society, there has been a remarkable progress in our social life. The major application area for the practical use of radio frequency (RF) signals is wireless transmission of information [ Dazey and Koons , ; Caorsi et al , ; Culhaoglu et al , ]. On the other hand, undesired electromagnetic (EM) waves that can cause interference or noise in various electronic and electrical devices such as radio receivers and telephone communications.…”