Our Services
High Voltage Isolation (HVI)
Boyles Electronics provides specialized telecommunications support for services entering the high-voltage corridor, including power substations, transmission towers, and generation facilities. We design, furnish, install, and troubleshoot high-voltage isolation equipment in accordance with IEEE 487.x standards to protect communication circuits from hazardous electrical environments. Our work includes fiber and copper facility placement, HVI protection arrangements, circuit provisioning, and on-site problem resolution. With decades of experience coordinating between utilities and telecom providers, BE ensures systems are installed safely, correctly, and in full compliance with regulatory standards.
Ground Potential Rise (GPR)
When a power fault occurs, the current which returns through the earth passes through the ground mat impedance. This current flowing through this impedance (resistance) creates a voltage per Ohm’s law equal to the current multiplied by the impedance and can be in the thousands or even tens of thousands of Volts and is called Ground Potential Rise or GPR. The ground grid of a substation is comprised of multiple horizontal conductors and vertical ground rods buried in the earth beneath the substation, and all metallic structures above ground are bonded to this grid via metallic “pigtails”. These connections keep all metallic infrastructure above ground at the same potential. During normal operating conditions, this GPR is effectively zero and is safe to touch.
Ground Potential Rise (GPR) Studies
Ground Potential Rise studies determine how fault current behaves at power substations during electrical faults. BE performs on-site data collection, including soil resistivity measurements and equipment verification, and uses advanced software modeling to calculate grid resistance and determine the Zone of Influence (ZOI).
We offer both full GPR studies and Mini-GPR studies depending on project requirements. Each study provides utilities and telecommunications providers with the information necessary to safely provision communications services, design grounding systems, and comply with regulatory and engineering standards. When greater accuracy is required, BE uses the Smart Ground Multimeter (SGM) to measure actual grid resistance, improving the precision of the analysis.
Ground Grid Location
Geotechnical Testing
System Ground Impedance
When a fault occurs in the power system, a phase lead comes into contact with ground or another phase conductor. When this happens, a high current flows through all available return paths to its source, such as a transformer’s secondary winding. The normal return path for the fault current includes numerous parallel paths including earth grounds, neutral conductors, shield wires, and any other incidental parallel metallic conductors such as water lines, telephone cable shields, and other metallic paths. The impedance of these combined parallel paths constitutes the “system ground impedance” and is important in the design considerations of a substation ground grid.
Ground Mat Impedance
That portion of the system ground impedance which flows back to its source through the earth, enters the substation by way of the earth and its connection to the ground grid. The earth is not a particularly good conductor and varies significantly depending on the resistivity of the varying layers of soil. Ground mat impedance is the impedance of only that current which flows back to its source through the earth via its connection to the ground grid. Also of note, the impedance of the earth is almost purely resistive with negligible reactive components (capacitive or inductive reactance), therefore the impedance of the earth is also equivalent to the resistance of the earth’s connection to the grid.
SGM Impedance Measurements
Using the Smart Ground Multimeter (SGM), we can accurately measure the impedance of the fault return path and specify how much of the return current will return through the earth and how much through other paths. The SGM is the only device capable of accurately measuring the impedance of an energized, in-service ground grid. BE’s testing supports safe operation, verifies new installations, and identifies changes in grid performance over time.
Soil Resistivity
Soil resistivity is a measurement used in substation design, grounding analysis, and the provisioning of telecommunications services, and it evaluates how well the soil conducts electricity. BE performs detailed soil resistivity surveys using industry-standard techniques and advanced tools and hardware, by way of the Super Sting R1 test set, and or the SGM, which will provide a two-layer model. These measurements help predict grid performance, guide substation design decisions, and determine fault behavior.
Touch Potential
During a power fault, when this voltage is applied to the ground grid, a voltage gradient is developed at the surface of the earth within and between the horizontal elements of the grid. If a technician is standing on a point inside this ground grid while touching a piece of metallic infrastructure (such as a steel upright or a cabinet), his hands and feet will be exposed to a difference of potential between the earth and the grounded metal object. This Voltage is referred to as Touch Potential, and BE can estimate this threat to safety. Step potential influences ground grid design and determines the spacing of horizontal elements to ensure a safe work environment. The resultant current that flows from the technician’s hand to his feet creates a shock that must be kept within safe limits. These voltages can be measured and are referenced to the maximum available fault current.
Step Potential
Similar to touch potential, step potential is the difference in Voltage between a technician’s feet while walking within the ground grid. Safety standards are developed that limit the amount of potential exposure to that which is less than life-threatening during a maximum fault current event.
Point-to-Point Continuity (Integrity)
The integrity of the ground grid is essential to the safety of personnel and the proper operation of equipment within the power delivery system. Point-to-point continuity checks confirm that the ground grid is working as intended. These measurements are made using the Safearth CS3 test set by connecting one lead to the first point of measurement and the other lead to the second (and subsequent) connection to the ground grid. These measurements should confirm that the different points on the ground grid are within just a few thousandths of an Ohm.