Magnetic field exposures for UK live-line workers

Area of Science:

• Biophysics
• Occupational Health
• Electromagnetic Field Dosimetry

Background:

• Live-line workers in the UK are exposed to 50 Hz non-uniform magnetic fields from high-voltage transmission lines.
• Understanding dosimetry for these workers is crucial for assessing potential health risks.

Purpose of the Study:

• To evaluate dosimetry for live-line workers exposed to magnetic fields from typical UK high-voltage transmission line configurations.
• To assess induced electric fields and current densities in critical organs under various worker postures and transmission line bundle types.

Main Methods:

• Simulations of twin-, triple-, and quadruple-conductor transmission line bundles with specific worker postures representing worst-case scenarios.
• Calculation of electric field and current density (averaged and non-averaged) in critical tissues like the retina, spinal cord, brain, and cerebrospinal fluid.
• Comparison of calculated values against UK and international regulatory guidelines for neural tissue (10 mA m(-2)).

Main Results:

• Averaged current densities exceeded guideline bounds in the brain, retina, and cerebrospinal fluid for a small number of postures and bundle configurations at 1 kA nominal load.
• Non-averaged current densities exceeded the suggested bound in the cerebrospinal fluid for all modelled scenarios.
• Non-averaged current densities also exceeded the bound in the retina for three postures involving a quadruple bundle.

Conclusions:

• While averaged current densities may exceed guidelines in specific scenarios, non-averaged current densities present a more consistent exceedance risk in the cerebrospinal fluid and retina.
• The findings highlight the importance of considering non-averaged current densities and specific worker postures in risk assessments for live-line workers.
• Further investigation into current-density averaging algorithms and their implications is warranted.