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Ann. Geophys., 23, 2107-2116, 2005
www.ann-geophys.net/23/2107/2005/
© European Geosciences Union 2005
Identifying power line harmonic radiation from an electrical network
S. M. Werner, C. J. Rodger, and N. R. Thomson
Department of Physics, University of Otago, Dunedin, New Zealand
Abstract. It has been suggested that the space environment is being polluted by power
line harmonic radiation (PLHR), generated from harmonics of the electrical
power transmission frequency (50 or 60 Hz) and radiated into the
ionosphere and magnetosphere by long power lines. While some in-situ
satellite measurements of PLHR have been reported, it has proved difficult to
confirm the source and overall significance. The electricity network of the
city of Dunedin, New Zealand, is tiny compared to the many large industrial
zones found outside New Zealand. However, the 1050Hz ripple control
signal injected into the local electrical grid at regular intervals as a
load-control mechanism provides an opportunity for identifying PLHR strengths
radiated from a spatially well defined electrical network. In-situ
observations by satellites should allow a greater understanding of PLHR and
its significance as man-made pollution to near-Earth space. Calculations have
been undertaken to estimate the strength of the radiation fields expected
from the ripple control signal which is injected into the Dunedin city
electrical network. We find that ground-based measurements will not be
sensitive enough for detection of the ripple control radiation fields, even
during the quietest winter night. While significant power penetrates the
lower ionosphere, this is well below the reported threshold required for
nonlinear triggering in the Van Allen radiation belts. Some radiated fields
at satellite altitudes should be detectable, allowing in-situ measurements.
At the altitude of the DEMETER mission, the radiated electric fields will not
be detectable under any ionospheric conditions. However, we find that the
radiated magnetic fields may be detectable by the DEMETER satellite at
certain times, although this will be very difficult. Nonetheless, there is
the possibility for future experimental campaigns.
Keywords. Magnetospheric physics (Magnetosphereionosphere
interactions; Plasma waves and instabilities) –
Ionosphere (Active experiments)
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