The purpose of conducting a Ground Potential Rise Study is to determine what the effects electrical faults will have on personnel and equipment within the fault area. In the event of a ground fault, understanding what the clearing time and the dissipation of the high-voltage event will be, allows for the safest and most cost effective grounding system design possible, without over engineering and staying within budgetary constraints.

GPR studies use a series of calculations to determine Step and Touch Voltages in accordance with specific standards. These studies also help to determine grid “hot spots” enabling the engineer to understand the behavior of grounding systems and to modify the designs accordingly.

What Else Should I know?
Copper wire communications cables within high voltage environments (substations, power plants, transmission towers) can be exposed to thousands of volts during a power system fault. In that instant, the entire site will experience a ground potential rise, and dangerous potential differences can occur between the power station and the remote (theoretically “zero”) ground of the telecommunication cable (central office). Any voltage difference will trigger a current flow, which as the potentials equalize, may have destructive consequences for personnel or sensitive electronics.

Each year, GPR electrical damage is costing the industry millions of dollars, yet few engineers or their managers are even aware of the phenomenon.