The present state of the technique of measuring ground resistance and impedance, earth resistivity, and potential gradients from currents in the earth, and the prediction of the magnitude of ground resistance and potential gradients from scale-model tests are described and discussed. Factors influencing the choice of instruments and the techniques for various types of measurements are covered. These include the purpose of the measurement, the accuracy required, the type of instruments available, possible sources of error, and the nature of the ground or grounding system under test. The intent is to assist the engineer or technician in obtaining and interpreting accurate, reliable data. The test procedures described promote the safety of personnel and property and prevent interference with the operation of neighboring facilities.
- Standard Committee
- PE/SUB - Substations Committee
- Status
- Superseded Standard
- Superseded by
- 81-2012
- Superseding
- 81-1962
- Board Approval
- 1981-09-17
- History
-
- ANSI Approved:
- 1984-09-04
- Published:
- 1983-03-11
Working Group Details
- Society
- IEEE Power and Energy Society
- Standard Committee
- PE/SUB - Substations Committee
Other Activities From This Working Group
Current projects that have been authorized by the IEEE SA Standards Board to develop a standard.
No Active Projects
Standards approved by the IEEE SA Standards Board that are within the 10-year lifecycle.
81-2025
IEEE Approved Draft Guide for Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials of a Grounding System
Practical test methods and techniques are presented for measuring the electrical characteristics of grounding systems. Topics addressed include safety considerations, measuring earth resistivity, measuring the power system frequency resistance or impedance of the ground system to remote earth, measuring the transient or surge impedance of the ground system to remote earth, measuring touch and step voltages, verifying the integrity of the grounding system, reviewing common methods for performing ground testing, reviewing instrumentation characteristics and limitations, and reviewing various factors that can distort test measurements.
These standards have been replaced with a revised version of the standard, or by a compilation of the original active standard and all its existing amendments, corrigenda, and errata.
693-1997
IEEE Recommended Practices for Seismic Design of Substations
Superseded by IEEE Std 693-2005, Recommendations for seismic design of substations, including qualification of each equipment type, are discussed. Design recommendations consist of seismic criteria, qualification methods and levels,structural capacities, performance requirements for equipment operation, installation methods, and documentation.
These standards have been removed from active status through a ballot where the standard is made inactive as a consensus decision of a balloting group.
81.2-1991
IEEE Guide for Measurement of Impedance and Safety Characteristics of Large, Extended or Interconnected Grounding Systems
Practical instrumentation methods are presented for measuring the ac characteristics of large, extended or interconnected grounding systems. Measurements of impedance to remote earth, step and touch potentials, and current distributions are covered for grounding systems ranging in complexity from small grids (less than 900m 2), with only a few connected overhead or direct burial bare concentric (2) neutrals, to large grids (greater than 20 000m 2), with many connected neutrals, overhead ground wires (sky wires), counterpoises, grid tie conductors, cable shields, and metallic pipes. This standard addresses measurement safety; earth-return mutual errors; low-current measurements; power-system staged faults; communication and control cable transfer impedance; current distribution (current splits) in the grounding system; step, touch, mesh, and profile measurements; the foot-equivalent electrode earth resistance; and instrumentation characteristics and limitations.
These standards are removed from active status through an administrative process for standards that have not undergone a revision process within 10 years.
81-2012
IEEE Guide for Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials of a Grounding System
Practical test methods and techniques are presented for measuring the electrical characteristics of grounding systems. Topics addressed include safety considerations, measuring earth resistivity, measuring the power system frequency resistance or impedance of the ground system to remote earth, measuring the transient or surge impedance of the ground system to remote earth, measuring step and touch voltages, verifying the integrity of the grounding system, reviewing common methods for performing ground testing, reviewing instrumentation characteristics and limitations, and reviewing various factors that can distort test measurements.