IEEE Std 2778:2020 pdf download.IEEE Guide for Solar Power Plant Grounding for Personal Protection.
This guide is primarily concerned with the grounding system design for ground-mount photovoltaic (PV)
solar power plants (SPPs) that are utility owned and/or utility scale (5 MW or greater). The focus of the guide
is on differences in practices from substation grounding as provided in IEEE Std 80.
This guide is not intended for the substations to interconnect the solar plant: however, if the substation is included within the plant, portions of this guide may be applicable. Similarly, this guide does not directly cover small-scale SPPs (such as rooftop type systems), substation grounding, or lightning protection.
1.2 Purpose
The intent of this guide is to provide guidance and information pertinent to the grounding practices in SPPs for personnel protection, specifically to identify differences between substation grounding (covered under IEEE Std 80) and SPPs.
This guide is primarily concerned with grounding practices related to personnel protection within SPPs for 50 liz or 60 liz systems.
2. Normative references
The following referenced documents are indispensable for the application of this document (i.e., they must be understood and used, so each referenced document is cited in text and its relationship to this document is explained). For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments or corrigenda) applies.
IEEE Std 8OTM. IEEE Guide for Safety mAC Substation Grounding.
IEEE Std 81, IEEE Guide for Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials ofa Grounding System.
3. Definitions, acronyms, and abbreviations
3.1 Definitions
For the purposes of this document, the following terms and definitions apply. The IEEE Standards Dictionary
Online should be consulted for terms not defined in this clause.3
collector system: All cables, underground cables, and/or overhead lines and switchgcar from solar inverter and step-up transforn1er sites to the SPP interconnect substation. The total number of ac collector system circuits is driven by the size of the substation transformer.
functionally grounded: A photovoltaic (PV) system that has an electrical reference to ground that is not solidly grounded.
personnel protection: Establishment of a grounding system capable of meeting touch and step voltage compliance within the SPP under fault conditions within the context of IEEE Std 80.
point of interconnection (P01): The location where the generation facility (SPP) connects to the transmission or distribution systems.
solar power plant (SPP): A group of electrically interconnected solar photovoltaic (PV) panels having one or more points of’ interconnection to the utility electric system.
split factor: A factor representing the portion of the rernotely-sourced symmetrical ground fault current that flows through the grounding system and earth compared to the total current.
SPP grounding system: The combination of all below-grade grounded objects within the solar power plant (SPP). including the interconnection of grounding through above-grade SPP structures. This may or may not include the interconnect substation, depending if this substation is within the SPPor not.
traditional power plants: Referring to those power plants that convert the chemical energy of a fuel into electrical energy (e.g., coal fired, gas fired, oil fired, etc.).
utility-scale SPP: A solar power plant (SPP) sized at 5 MW or greater.IEEE Std 2778 pdf download.