NS189

NS189: Oil Containment for Major Substations

The objective of this standard is to specify the design requirements for oil containment on site during the day-to-day operation of major substations as well as in emergency situations.

Scope

This Network Standard details the design requirements for oil containment within major substations. It also includes provisions to minimise the spread of fire.
This Standard applies to the oil containment systems used for new major substations with primary voltages of 132, 66 and 33 kV. It also applies to existing major substations with these primary voltages where it is reasonably practicable to do so.

This Standard does not include provisions for pole top transformers and capacitors, distribution and customer substations, kiosks, regulators, tap changer auto transformer substations, reclosers or oil filled cables and their associated pressure vessels. 

This Network Standard deals with the two main types of oil-water separation systems currently used by Ausgrid:

1. Parallel Plate Separator (PPS) - a closed drainage design with bund storage which uses a pumped oil-water separator system.
2. Enhanced Gravity Oil and Water Separator (EGOWS) - a gravity drainage system and tank which uses a delayed release principle to separate the oil and water.

Alternative oil-water separation systems can be proposed for use, subject to suitable performance testing and verification of compliance.

References in this Network Standard to a particular type of oil-water separator shall, where appropriate, also be applicable to an approved alternative system of comparable design.

Oil containment systems shall be designed to meet the requirements of this Network Standard and the relevant parts of AS 2067 and AS 1940. Where a conflict occurs, the requirements of this Network Standard shall prevail.