2021 Volume 13 Issue 2 Pages 73-82
The short-circuit current flowing from the feet to the ground was numerically analyzed for human models located under transmission lines. The human model with wet feet stood upright on the ground, while holding an overhead metal plate or frame with both arms. A vertical uniform alternating current electric field of 3 kV/m and 50 Hz was applied to the model. The short-circuit current was analyzed by systematically changing the parameters such as height (≤9.34 m), width (≤9.34 m), thickness (≤5.4 cm), and holding point height (≤2.367 m) of the metal object. Each parameter's value was examined when the short-circuit current exceeded the international protection guideline value of 500 µA. Furthermore, the short-circuit current was modeled through a complete quadratic polynomial including all related parameters, and the fitting coefficient was calculated by the nonlinear least squares method. The obtained polynomial can express the analyzed short-circuit current with a difference of approximately −2.64%～3.90% in the case of plate holding model analysis. We believe this quadratic polynomial is appropriate because the short-circuit current is proportional to the amount of surface charge, which strongly depends on the surface area being analyzed.
