This Guide addresses the high level aspects of policy associated with power system earthing. It provides a framework for managing earthing related risk associated with electrical power systems to meet societally acceptable levels. This framework provides principles for the design, installation, testing and maintenance of the earthing systems associated with power system assets on a.c. systems with nominal voltages up to EHV. A central part of this framework is a probabilistic derivation of allowable voltage criteria and exposure under fault conditions. It is intended for use by electrical utilities and HV asset owners, operators and customers, specifically regarding:
- major substations
- distribution networks
- transmission lines
- power stations, and
- large industrial systems.
It does not apply to the design or installation of any of the following which may be covered by other standards or codes:
- customer premises LV earthing (refer AS3000)
- earthing systems associated with d.c. systems
- earthing systems associated with electric railway traction systems
- erthing systems on ships and off-shore installations
- test sites
- mining equipment and installations
- electrostatic equipment (for example, electrostatic precipitators).