NS190 OIL CONTAINMENT OPERATIONAL REQUIREMENTS FOR MAJOR SUBSTATIONS (NW000-S0055)

NS190 Oil Containment Operational Requirements for Major Substations

1.0 PURPOSE
This Network Standard details the general requirements for the operation of oil containment systems at major substations.
The primary objectives of this document are to:
• ensure a consistent approach is undertaken for the management of oil containment systems, and
• provide clear instructions on the general operational requirements for oil containment systems.

2.0 SCOPE
The scope of this document is to provide guidelines for the operation of oil containment systems at major substations, namely Zone and Sub-transmission Substations.
This document does not include provisions for pole top transformers & capacitors, distribution & customer substations, regulators, tap changer auto transformer substations, reclosers or oil filled cables and its associated pressure vessels.
Ausgrid has a number of different oil containment systems that have different and specific operating requirements. The as-built oil containment drawings will document the oil containment installed at each substation.
Oil containment operational activities may include inspection of oil depths, sludge depth and stormwater discharge concentrations, cleaning and waste removal.
This document applies to all persons including Ausgrid, Contractors, Sub-Contractors and associates, and employees of any of the above.

3.0 REFERENCES
3.1 General
All work covered in this document shall conform to all relevant Legislation, Standards, Codes of Practice and Network Standards. Current Network Standards are available on Ausgrid’s Internet site at www.ausgrid.com.au.
3.2 Ausgrid documents
• Company Form (Governance) – Network Document Endorsement and Approval
• Company Procedure (Governance) – Network Document Endorsement and Approval
• Company Procedure (Network) – Production / Review of Network Standards
• Electrical Safety Rules
• Electricity Network Safety Management System Manual
• NS174 Environmental Procedures
• NS181 Approval of Materials and Equipment and Network Standard Variations
• NS189 Oil Containment for Major Substations
• NS212 Integrated Support Requirements for Ausgrid Network Assets
• Public Electrical Safety Awareness Plan

3.3 Other standards and documents
• AS 2865 Confined Spaces
• AS/NZS 3500 Plumbing and Drainage (Series)
• ENA Doc 001-2008 National Electricity Network Safety Code
3.4 Acts and regulations
• Electricity Supply (General) Regulation 2014 (NSW)
• Electricity Supply (Safety and Network Management) Regulation 2014
• Environmentally Hazardous Chemicals Act 1985
• Protection of the Environment Operations Act 1997
• Protection of the Environment Operations (General) Regulation 1998
• Protection of the Environment Operations (Waste) Regulation 1996
• Work Health and Safety Act 2011 and Regulation 2011
• All relevant WorkCover documentation.

4.0 DEFINITIONS
Accredited
Service Provider
(ASP)

An individual or entity accredited by the NSW Government Trade &
Investment in accordance with the Electricity Supply (Safety and Network
Management) Regulation 2014 (NSW).

Approved
Equivalent

Equipment or materials approved in writing by Ausgrid.

Bund A wall/barrier of sufficient height constructed around fluid filled equipment
to contain spillage of liquids.
Butterfly valve A valve used to close the outlet of the oil containment tank.
Business
Management
System (BMS)

An Ausgrid internal integrated policy and procedure framework that
contains the approved version of documents.

Chain of
Custody Form

Chronological documentation detailing the collection, custody, control,
transfer and analysis of samples.
Designer The designer is the nominated party responsible for the layout and design
of the oil containment system under the overall direction of Ausgrid. The
designer may be an internal group within Ausgrid, or an external party
appointed for the project.
Document
control

Ausgrid employees who work with printed copies of document must check
the BMS regularly to monitor version control. Documents are considered
“UNCONTROLLED IF PRINTED”, as indicated in the footer.
EGOWS Enhanced Gravity Oil and Water Separator. An oil containment tank
developed by the UNSW. The tank contains stainless steel baffles and flow
retarding devices.
Flame trap A pit with a down turned pipe used as a fire quenching mechanism.
Gravel Stone including blue metal and river stone used as a flame-quenching
medium.
Knife Gate Valve Manual valve or penstock used to close outlet to an oil containment tank.
Major Substation For the purpose of this document, major substation means zone and sub-
transmission substations with primary voltages of 132, 66, and 33 kV.

NS190 Oil Containment Operational Requirements for Major Substations Amendment No 1

For Official use only

Non Return
Valve

Also called a flap valve, it is a one way valve that prevents flow back up into
the pipe.

Network
Standard

A document, including Network Planning Standards, that describes the
Company’s minimum requirements for planning, design, construction,
maintenance, technical specification, environmental, property and metering
activities on the distribution and transmission network. These documents
are stored in the Network Category of the BMS repository.

Oil Containment
System

The oil containment system refers to the transformer bunds, together with a
suitable combination of flame traps, pipes, oil containment tank and Parallel
Plate Separator as required. The oil containment system is not designed as
an oil storage system. It is designed for emergency situations and the
treatment of minor oil contamination from transformer bunds.

Parallel Plate
Separator (PPS)

A gravity separation device that uses parallel plates to coalesce and separate
oil and water.
PPM Parts per million. An oil-water concentration of 10 ppm equals 10mg/l
which is equivalent to visibly free of oils and greases, i.e. no visible oil.
Review date The review date displayed in the header of the document is the future date
for review of a document. The default period is three years from the date of
approval however a review may be mandated at any time where a need is
identified. Potential needs for a review include changes in legislation,
organisational changes, restructures, occurrence of an incident or changes
in technology or work practice and/or identification of efficiency
improvements.
Single Stage
Separator

An oil containment tank that consists of a single chamber that discharges
water from the bottom of the tank.
Sludge Judge Device used to check the depth of sludge within the oil containment tank.
Surfactants A substance, which emulsifies, disperses or dissolves other substances (eg.
a detergent).
Tank Profiler Clear plastic tube lowered into the oil containment tank to determine oil
depths.
Triple Stage
Separator

An oil containment tank that consists of three chambers through which the
contaminated water runs through consecutively. Water is discharged from the
bottom of the third chamber.
Waste Captured oil and sediment within the oil containment system.

NS190 Oil Containment Operational Requirements for Major Substations Amendment No 1

For Official use only

5.0 OIL CONTAINMENT DESIGN
The design requirements for oil containment at major substations are outlined in NS189 Oil
Containment for Major Substations.

6.0 OPERATIONAL REQUIREMENTS
6.1 General
6.1.1 Technical Maintenance Plans
Ausgrid has developed a series of Technical Maintenance Plans (TMPs) for substations which
includes Maintenance Standards for the various types of oil containment systems in operation.
These TMPs are regularly updated and include a detailed description of the required maintenance
activities and the frequency of inspection for oil containment facilities.
All current TMPs and Maintenance Standards are to be implemented as part of the operational
requirements of this document.
6.1.2 Surfactants
The use of surfactants will disturb the operation of a Parallel Plate Separator or oil containment
tank and oil and water separation may not be properly achieved. Where surfactants have been
used, the entire contents of the oil containment system must be emptied and the system recharged
with clean water to ensure the operational performance criteria can be achieved.
6.1.3 Confined spaces
All work in confined spaces are to be undertaken in accordance with the Work, Health and Safety
(WHS) Act and Regulation and with AS 2865 Confined Spaces.
Enclosed tanks are confined spaces and will require signage, entry permits, standby personnel,
gas detectors, training and rescue/escape procedures in accordance with AS 2865 and WHS
Regulation.
For enclosed tanks, personnel shall enter the tank wearing a full harness and where possible
should remain attached to a mechanical retrieval mechanism which can be operated from outside
the tank. Class 3 fall arrest devices are preferred and provide both fall arrest and retrieval
functions. Fall arrest protection is generally required when climbing vertical ladders where the fall
distance may exceed 2 metres.
6.1.4 Other safety issues
Waste removal and waste sampling may have specific safety & PPE requirements and must be
taken into consideration in the preparation of Safe Work Method Statements (SWMS).
6.2 Oil handling, waste and other environmental requirements
NS174 Environmental Procedures provides guidance to assist Ausgrid Employees with
environmental issues including the handling, storing, transporting and disposing of oil, waste and
other materials in accordance with legislative requirements.
6.3 Operational performance criteria
The relevant performance criteria that are applicable to Ausgrid’s oil containment systems are
listed in Table 1 below.