Calculation of Transmission Line Worker Electric Field Induced Current Using Fourier-Enhanced Charge Simulation

Abstract

Exposure to quasi-electrostatic field induced currents is a hazard of live-line transmission work. These steady-state induced currents are typically less than 1 mA, and their sensory effects range from imperceptible to painful depending on the person and conditions such as contact area and duration. Permanent injury from these currents is unlikely but they can distract workers, increasing the risk of injury from falls or other dangers. Identifying contact current severity and training workers can help reduce the risk of accidents. Measuring induced currents along a climbing route is time-consuming and simulation is challenging because of the geometric complexity of the worker, the transmission structure, conductor bundles, and electric fields in the climbing space. This research explores the suitability of a recently published adaptation of the charge simulation method for calculating worker-induced currents. The method uses Fourier principles to improve computational efficiency while explicitly modeling all bundle subconductors. The research also examines simplifications for modeling lattice structures and human geometry. Calculated currents compare well to measurements for a worker climbing a 400 kV lattice structure. This indicates the method is a practical option for calculating steady-state contact current severity. A simple calculation is suggested for estimating these currents.