Electricity Today T&D Magazine

How to guard utility personnel from shock hazards

BY JEFF JOWETT, Megger

In the power industry, safety is just as important a function as performance. Safety considerations, parameters, and methods of implementation are an integral part of any electrical system. A most important element is the grounding system. This system performs several functions, not the least of which is safety. Substations are active in fault clearance, and personnel working in and around them, as well as pedestrians passing in the vicinity, need to be protected. When a fault condition occurs, the grounding electrode (grid) must be sufficient to equalize potentials...

Step Potential

Step potential is the step voltage between the feet of a person standing near an energized grounded object. It is equal to the difference in voltage, given by the voltage distribution curve, between two points at different distances from the electrode. A person could be at risk of injury during a fault simply by standing near the grounding point.

Touch Potential

Touch potential is the touch voltage between the energized object and the feet of a person in contact with the object. It is equal to the difference in voltage between the object and a point some distance...