Vorhaben 3608S03011 - DORIS - Bundesamt für Strahlenschutz

Summary
Task
Actual and worst case electric and magnetic immissions in the neighbourhood of overhead
and underground high voltage power lines had to be determined by measurements resp.
calculations and the effect of different technical realisations of the power lines on the immissions
had to be compared. The effect of power lines on the low frequency magnetic field exposure
in dwellings had to be investigated.
Work packages
The following works have been carried out:
• Survey of previous investigations of the immissions in the neighbourhood of power lines
and in dwellings as well as of available procedures to measure or calculate the electric
and magnetic immissions caused by power supply facilities
• Development of a simple computer program for the calculation of the magnetic fields in
the neighbourhood of power lines
• Measurement of the electric and magnetic immissions in the neighbourhood of overhead
and underground power lines
• Extrapolation of immissions for maximum workload
• Measurements of the magnetic fields in dwellings near to as well as far from power lines
• Extrapolation of exposure to magnetic fields in dwellings near power lines for maximum
workload
Results
The results of measurements and calculations of the fields caused by high voltage power
lines and of the measurements in dwellings agree with the results of earlier studies to a large
extent:
• The level of the immissions caused by overhead and underground power lines strongly
depends on the constructive and operational parameters. Critical parameters are
- the strength of the current on the line because this has a direct effect on the strength
of the magnetic field and it influences the sagging of overhead power lines which in
turn affects the magnetic as well as the electric field
- the number of the wires and their spatial arrangement
- the mounting height and the constructive sagging of overhead power lines and the
hauling depth of underground power lines
- the relative arrangement of the phase wires and the current asymmetry
• The immissions caused by underground cables outside the hauling corridor are substantially
lower than those caused by overhead power lines of the same voltage level.
• The low frequency magnetic field exposure increase with the density of flats, it is higher
in apartment buildings than in single-family houses.
• High voltage overhead power lines in the neighbourhood can lead to exposures substantially
higher than those in dwellings faraway from power lines (see below). Near electrical
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