Ground Potential Rise Studies
FAQ
What is Ground Potential Rise (GPR)?
Ground Potential Rise (GPR) is the increase in electrical potential at a grounding point during a fault condition in an electrical system. When a fault occurs, large fault currents flow through the grounding system into the earth, causing the local ground potential to rise significantly above true earth potential. This elevated voltage can create dangerous step and touch potentials that pose serious shock hazards to personnel and can damage connected equipment.
What is a Ground Potential Rise study?
A GPR study is an engineering analysis that evaluates the magnitude of ground potential rise at a substation or electrical facility during a fault event. The study calculates the potential gradients across the site, identifies step and touch potential hazards, assesses the effectiveness of the existing grounding system, and recommends mitigation measures to bring hazard levels within safe limits.
Who needs a Ground Potential Rise study?
GPR studies are typically required for electrical substations, generating stations, transmission and distribution facilities, telecommunications sites connected to power infrastructure, and any facility where fault currents could create dangerous ground potential differences. Utilities, municipalities, and industrial operators with high voltage infrastructure commonly require GPR studies as part of their safety and compliance programs.
What are step and touch potentials and why are they dangerous?
Step potential is the voltage difference between two points on the ground surface separated by one step (approximately one metre), which a person could experience while walking near a fault location. Touch potential is the voltage difference between the ground surface and a grounded object that a person could contact simultaneously. Both can deliver dangerous or lethal electric shocks to personnel during a fault event, even if they are not directly involved in the electrical system.
What does Sabino Electric's GPR study include?
Sabino Electric’s engineers perform a comprehensive GPR study including soil resistivity testing, fault current analysis, grounding system modelling, and calculation of step and touch potentials across the site. The study also includes testing of existing and newly installed grounding grids to confirm their performance against the study results. Recommendations for grounding improvements are provided where hazard levels exceed safe limits.
Does Sabino Electric perform grounding grid testing as part of the GPR study?
Yes. Sabino Electric performs physical testing of existing and newly installed grounding grids to verify their actual performance and confirm acceptability against the GPR study findings. This combination of analysis and field testing provides a complete picture of grounding system performance and compliance.
Where does Sabino Electric provide Ground Potential Rise study services?
Sabino Electric provides GPR study services throughout Arizona, and through the BCES Global network of subsidiary companies, across the rest of North America.
How do I arrange a Ground Potential Rise study with Sabino Electric?
Sabino Electric provides GPR study services throughout Arizona, and through the BCES Global network of subsidiary companies, across the rest of North America.
How do I arrange a Ground Potential Rise study with Sabino Electric?
Contact Sabino Electric at 520-623-6061 or through the request form at sabinoelectric.com. Our engineering team will assess your facility’s requirements and provide a proposal covering the full scope of analysis and field testing.
