Study on Electromagnetic Environmental Impact of AC Overhead Transmission Lines with Different Erection Methods

This study investigates the electromagnetic environmental impact of AC overhead transmission lines with different erection methods, focusing on power frequency electric field (measured by electric field intensity) and power frequency magnetic field (characterized by magnetic induction intensity). Based on the equivalent charge theory, simulations and calculations were conducted using the Matlab Radiation Calculate platform, analyzing the effects of line-to-ground distance, erection mode, conductor layout, and phase sequence arrangement on the electromagnetic field. For single-circuit lines, the inverted triangle (compact) layout exhibits more concentrated field intensity distribution and a smaller high-field-strength area compared to equilateral triangle and horizontal layouts. For double-circuit or multi-circuit lines on the same tower, reverse phase sequence arrangement effectively reduces both power frequency electric field intensity (maximum 2355 V/m vs. 3178 V/m for in-phase sequence) and magnetic induction intensity (4.137 μT vs. 6.601 μT for in-phase sequence). Increasing the line-to-ground height significantly decreases the maximum power frequency electric field intensity (reducing by 0.4–1.6 kV/m per 1m height increase), while its impact on magnetic induction intensity is linearly slight. All calculated values comply with GB8702-2014 standards (electric field ≤4000 V/m, magnetic induction ≤100 μT for public exposure). The power frequency electric field intensity is identified as the key electromagnetic environmental factor requiring attention. This study provides a theoretical basis for optimizing transmission line erection to mitigate electromagnetic environmental impacts.