NS259

NS259: Requirements for Protection System Segregation

The purpose of this standard is to describe the physical, electrical and logical segregation requirements for protection equipment and functions within zone and subtransmission substations.

Scope

Inclusions
Segregation between ‘A’ Protection and ‘B’ Protection:

• Relays, links, terminals and other minor panel hardware
• Cabling between primary plant and panels
• Wiring between panels and inter-panel
• Communications paths per NS203
• AC/DC Boards, Batteries & Chargers

Segregation between Low Voltage Power and Protection/SCADA:

• Low Voltage Power Cables and Fibre Optic cables
• Low Voltage Power Cables and Copper protection cables
  Some exceptions are allowed. Refer to Clause 3.4.2.

Segregation between Primary Plant and Protection/SCADA:

• High Voltage Power Cables and Fibre Optic cables
• High Voltage Power Cables and Copper protection cables
• Location of HMI, Protection Panels, and Switchgear in the Control Room

Segregation between groups of secondary equipment:

• Secondary equipment for separate items of primary plant

Exclusions

• Cables which form part of communications systems between substations.
• Segregation of other services in the substation (fire, telecommunications etc).