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National Electric Energy Testing, Research & Applications Center
GROUNDING AND SURGE PROTECTION SERVICES

GROUND SYSTEM DESIGN/TESTING

Maintaining step and touch voltages below tolerable limits is basic to a safe ground grid design. In addition, ground designs for poles and towers must limit transient ground potential rise. NEETRAC can design and analyze any of these grounding systems using state of the art software.

To ensure that the grounding design that we deliver is safe and reliable, the following variables are considered:

  • Worst case fault conditions
  • Alternate ground paths
  • Site soil resistivity and soil model
  • Surface cover materials
  • Strategic placement of grounding elements
  • Sizing of grounding elements
Touch Voltage Profile for a
500/230/115 kV Substation

NEETRAC has the tools and expertise to assist you with a wide variety of ground system testing needs. Our complete line of testing services includes:

  • SmartMeter®
    • Ground resistance (stand-alone or with ground wires)
    • Step, touch, and transfer voltages
    • Soil resistivity
    • Coupled voltages (60 Hz) on I & C circuits
    • Ground integrity test (can use 300-ampere test set)
  • Mobile 200 kV Impusle Generator
    • Transient ground potential rise
    • Coupled voltages (impulse) on I & C circuits
  • Gravel Resisitivity Tester
    • Testing of surfacing materials
  • Ω-Check®
    • Neutral (UG or OH) integrity testing

Training is also offered to help you utilize any of these testing techniques. Give us a call.

SURGE PROTECTION

The National Lightning Safety Institute estimates that lightning costs U.S. businesses five billion dollars annually in damaged equipment and downtime. If transient voltages are adversely affecting your plant or substation, NEETRAC can help. We have the expertise to analyze transient voltage problems and provide workable solutions to protect relays, RTUs, CEMS and enunciators from lightning and switching surges.

Our investigation procedures are simple and direct. To establish the right level of protection, we:

  • Review past and present incident histories
  • Inspect affected equipment and circuits
  • Review cable shield termination practices
  • Perform integrity tests on cable shields and circuit grounds
  • Test for coupled voltages, 60 Hz and impulse (if required)
Damaged 480-V Fuse-Holders Due to Switching Surge in an Electric Boiler

200-kV Impulse Generator on Trailers

High freq. Common Mode Voltage (V/A) on 4#10 Non-shielded Cable

Low freq. Common Mode Voltage (V/A) on 4#10 Non-shielded Cable

STRAY VOLTAGE ANALYSIS

Electric shocks from stray voltages are caused by:

  • Unbalanced phases
  • Earth ground on120 volt circuits
  • Corroded neutral connections
  • Improper wiring

No matter where they occur, NEETRAC can pinpoint the source of stray voltage problems and recommend solutions. Both field investigations and computer analysis are available to find the right solution for each situation. We have corrected stray voltage problems:

  • at dairy, swine or poultry farms
  • around houses
  • near swimming pools
  • at boat docks
  • in RV campgrounds
Analysis

Measurement

Mitigation

Let NEETRAC work with you to assess the cause of electric shock problems and recommend a reliable, effective course of action.

Last revised on October 31, 2011