IEEE Guidelines for Safety in IEEE 80 AC Substation Grounding

EUROLAB laboratory provides testing and compliance services within the scope of IEEE 80 standard. The IEEE 80 standard primarily concerns conventional or gas-insulated outdoor AC substations. Distribution, transmission and generation plant substations are included. With due care, the methods described herein can also be applied to indoor portions of such substations or to substations that are purely indoor.

No attempt is made to correct the grounding problems specific to DC substations. A quantitative analysis of the effects of lightning surges is also beyond the scope of this guide.

The purpose of this manual is to provide guidance and information regarding safe grounding practices in AC substation design. The specific purposes of this guide are:

• As a basis for design, determine the safety limits of potential differences that can exist in a substation under fault conditions between points of contact with the human body.
• Review substation grounding practices and develop safety criteria for design with specific reference to safety.
• Provide a procedure for the design of practical grounding systems based on these criteria.
  Develop analytical methods to help understand and solve typical voltage gradient problems.
• Provide benchmarks to compare the results of IEEE Std 80™ equations with commercially available software programs.

This guide primarily deals with safe grounding practices for power frequencies in the 50 Hz to 60 Hz range. Problems specific to DC substations and the effects of lightning surges are beyond the scope of this guide. However, a grounding system designed as described here will provide some degree of protection against steep wave pre-surges entering the substation and passing through grounding to ground.

This release introduces calculations to determine TCAP for unspecified materials. This information can be used to calculate TCAP for different combinations of bimetallic electrodes used in grounding systems. This version also introduces benchmarks. Benchmarks have two purposes. First, benchmarks compare the equations in IEEE Std 80 with commercially available ground grid design software. The comparisons show where IEEE Std 80 equations work well and their limitations. Second, benchmarks provide software users a way to verify their understanding of the software.

Our organization, EUROLAB, provides IEEE Guide services for safety in AC substation grounding within the framework of national and international standards, with its trained and expert staff and advanced technological equipment, among numerous test, measurement, analysis and evaluation studies. Contact EUROLAB to get testing services under the IEEE 80 standard.