NS222

NS222: Major Substation Earthing Design

This network standard specifies the design requirements and processes for major substation earthing that form part of the Ausgrid network.

Scope

The scope of this standard is limited to the zone and sub-transmission substation earthing design
with consideration of the connectivity between the following components: 

• The substation grid,
• The embedded earthing system,
• The lightning protection system,
• The substation plant,
• Sub-transmission and distribution earth terminations.

This standard sets out the objectives and basic configurations required of a major substation earthing design. It also specifies procedures and acceptable practice by which these shall be achieved.

For other network earthing requirements, refer to:

• NS116 for distribution substation earthing requirements.
• NS260 for earthing system performance issues, such as feeder interconnectivity and system-wide fault current distribution.
• NS264 for major substation lightning protection requirements.