Recent Publications from the Group
The following have all been recently submitted, accepted for publication or have now been published:
Comparisons of ground level measurements of ion concentration and potential gradient upwind and downwind of HV power lines in corona.
James C. Matthews, Alison J. Buckley, Matthew D. Wright and Denis L. Henshaw
Journal of Electrostatics, 2012, vol 70(4), pages 407-417
ABSTRACT
Simultaneous ion concentration and potential gradient measurements were made at AC high voltage power lines using ion mobility spectrometers and electric field mills. A significant (p < 0.01) change in central tendency and variability of ion concentration and potential gradient can occur downwind of power lines. In 3 out of 8 downwind measurements, there was a discrepancy of sign between the overall mean of these quantities, attributed to ion dispersion and ion-aerosol attachment. While ion concentrations give a greater indication of personal exposure, potential gradient measurements are more appropriate for assessment of the behaviour of a power line.
The effect of weather on corona ion emission from AC high voltage power lines
James C. Matthews
Atmospheric Research, 2012, vol 113, pages 68-79
ABSTRACT
There is a natural potential gradient caused by global thunderstorm activity that can be measured from the ground using electric field mill meters. High voltage power lines can produce corona ions by ionising the air, depending on the ambient weather conditions. A fixed site monitoring station recorded atmospheric potential gradient and weather conditions near to two AC high voltage power lines throughout 2008. High humidity correlated with negative potential gradient both upwind and downwind of power lines and high wind speed correlated with greater potential gradient disruption. Rain caused the greatest disruption to potential gradient, causing negative fields and an increased standard deviation. Multiple regression analysis also showed that that humidity and wind speed have an effect on the production of corona ions and quantile regression plots indicate a clear trend of decreasing mean potential gradient with increasing wind speed and relative humidity.
Diurnal variations of atmospheric potential gradient disruption near to high voltage power lines
James C. Matthews
Journal of Atmospheric and Solar-Terrestrial Physics, 2012, vol 77, pages 235-240.
ABSTRACT
The Earth's background potential gradient (PG) has a diurnal cycle (the