| Publisher | IEEE |
|---|---|
| Type | Guide |
| Scope | Guidance on the design of grounding systems for outdoor AC substations so that step and touch voltages remain within tolerable limits during ground faults. |
| Who uses it | Substation and transmission engineers, grounding specialists, utility engineers, consultants and industrial owners of high-voltage installations. |
| Edition note | Refer to the publisher for the current edition. |
What It Is
IEEE 80 is the principal IEEE guide for designing safe grounding systems in AC substations. Its central objective is to protect people in and around a substation during a ground fault, when large currents flow into the earth and create dangerous voltage differences at the surface. The guide also supports the related goals of providing a path for fault current and maintaining the reliability of equipment.
The guide sets out a design procedure. Engineers characterize the soil, determine the maximum grid current, select conductor sizes, calculate tolerable step and touch voltages for the human body, and then design and iterate the ground grid until calculated mesh and step voltages fall below the tolerable values. It also discusses special concerns such as transferred potentials, fences, gas-insulated substations and the effect of surface materials like crushed rock.
Why It Matters
Grounding failures are silent until a fault occurs. A poorly designed grid can expose workers and the public to lethal voltages during a fault, even if the substation otherwise operates normally. IEEE 80 is the widely recognized engineering basis for showing that a design is safe.
Utilities, regulators and owners commonly require compliance with IEEE 80 in specifications. Its concepts also inform safety practice for line and substation workers, including temporary grounding and equipotential work zones.
Key Concepts
- Ground potential rise (GPR) — the maximum voltage a substation grounding system reaches relative to remote earth during a fault.
- Touch voltage — the potential difference between a grounded structure and a person's feet when the person touches that structure during a fault.
- Step voltage — the potential difference across a person's feet spaced about one step apart on the surface during a fault.
- Mesh voltage — the maximum touch voltage within a grid mesh, often the governing design criterion.
- Tolerable body current — the current the human body can withstand for a given fault duration without ventricular fibrillation, used to set safety limits.
- Soil resistivity — the electrical resistivity of the earth, measured in the field and often modeled as layers, which strongly affects grid performance.
- Surface layer — a high-resistivity material such as crushed rock placed over the grid to increase contact resistance and tolerable voltages.
- Transferred potential — a hazardous voltage carried outside the substation by conductors such as fences, pipes or communication cables.
Who Should Know It
- Substation design and grounding engineers
- Utility protection and planning engineers
- Electrical consultants for industrial high-voltage facilities
- Construction and commissioning engineers testing grounding systems
- Safety professionals assessing substation hazards
Related Standards
- IEEE 81 — the IEEE guide for measuring earth resistivity, ground impedance and earth surface potentials, which supplies field data for IEEE 80 designs.
- OSHA 29 CFR 1910.269 — the federal rule governing safety of workers in substations and on power lines.
- IEEE C37 Series — fault clearing times from protection systems affect tolerable voltage calculations.
- IEEE 837 — the IEEE standard for qualifying permanent connections used in substation grounding.
How ASEEE Uses It
ASEEE power systems and substation programs map learning outcomes and assessments to IEEE 80 concepts, including soil characterization, step and touch voltage criteria and grid design reasoning. See related ASEEE programs.
ASEEE Programs Referencing This Standard
Educational summary only. ASEEE is not the publisher of this document and this page does not reproduce or replace it. Always consult the current official edition from IEEE for requirements.