Working Group Details
WGG6 - Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials of a Grounding System
|Working Group Chair||
|IEEE Program Manager|
P81 - Guide for Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials of a Grounding System
The test methods and techniques used to measure the electrical characteristics of the grounding system include the following topics: a) Establishing safe testing conditions b) Measuring earth resistivity c) Measuring the power system frequency resistance or impedance of the ground system to remote earth d) Measuring the transient (surge) impedance of the ground system to remote earth e) Measuring step and touch voltages f) Verifying the integrity of the grounding system g) Reviewing common methods and procedures for performing ground testing h) Reviewing instrumentation characteristics and limitations i) Reviewing various factors that can distort test measurements
IEEE 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.
Superseded by IEEE Std 693-2005 Recommendations for seismic design of substations, including qualification of each equipmenttype, are discussed. Design recommendations consist of seismic criteria, qualification methods and levels,structural capacities, performance requirements for equipment operation, installation methods, anddocumentation.