HPC_9DJ_23_0001_2012_Sub

Standard: Substation Installation Technical Requirements Standard Number: HPC-9DJ-23-0001-2012

DM# 3666797 Page 2 of 36 Print Date 16/09/2013

Horizon Power Corporation: HPC-9DJ-23-0001-2012

Uncontrolled document when printed. Printed copy expires one week from print date. Refer to Document No. for current version.

Document Control

Author Name: Anthony Seneviratne

Position: Senior Standards Engineer

Document Owner

(May also be the Process Owner)

Name: Justin Murphy

Position: Manager Asset & Works

Approved By * Name: Justin Murphy

Position: Manager Asset & Works

Date Created/Last Updated September 2013

Review Frequency ** 3 yearly

Next Review Date ** September 2016

* Shall be the Process Owner and is the person assigned authority and responsibility for managing the whole process, end-to-end, which may extend across more than one division and/or functions, in order to deliver agreed business results.

** Frequency period is dependent upon circumstances maximum is 5 years from last issue, review, or revision whichever is the latest. If left blank, the default shall be 1 year unless otherwise specified.

Revision Control

Revision Date Description

0 10/09/2013 Initial Document Creation

STAKEHOLDERS The following positions shall be consulted if an update or review is required:

Manager Assets & Works

Manager Engineering Services

Manager Engineering Systems Planning




TABLE OF CONTENTS

1 PURPOSE .................................................................................................... 62 APPLICATION ............................................................................................. 63 NORMATIVE REFERENCES ....................................................................... 63.1 Legislation and Standards ........................................................................................ 63.2 Definitions ................................................................................................................ 74 SUBSTATION INSTALLATION REQUIREMENTS .................................... 104.1 General .................................................................................................................. 104.2 Instructions, Procedures and Standards ................................................................ 105 GENERAL CONCEPTS ............................................................................. 115.1 Types of Distribution Substations ........................................................................... 115.2 Modular Packaged Substations (MPS) .................................................................. 115.3 Non MPS Arrangements ........................................................................................ 125.4 Customer Owned Substations ................................................................................ 126 MINIMUM REQUIREMENTS FOR SUBSTATION INSTALLATIONS ........ 136.1 Access .................................................................................................................... 136.1.1 Substation Site Access ......................................................................................................... 136.1.2 Substation Gatic Cover Access ............................................................................................ 136.1.3 Equipment ............................................................................................................................. 136.1.4 Personnel Access ................................................................................................................. 136.1.5 Location from Street Front .................................................................................................... 136.2 Site Requirements and Preparation ....................................................................... 146.2.1 Sole Use and Customer Owned Substations ....................................................................... 156.3 Requirements for Buildings .................................................................................... 156.3.1 General Requirements .......................................................................................................... 156.3.2 Aisles and Escape routes ..................................................................................................... 166.3.3 Doors .................................................................................................................................... 166.3.4 Ventillation .............................................................................. Error! Bookmark not defined.6.3.5 Cable Trenches ..................................................................................................................... 177 POINT OF SUPPLY .................................................................................... 187.1 District and Sole Substations ................................................................................. 187.2 Customer Owned Substations ................................................................................ 188 FIRE PROTECTION OF SUBSTATIONS ................................................... 19




8.1 MPs and Non MPS Substations installed outdoors ................................................ 198.2 Substations Installed Indoors (Including Customer Owned Substation) ................ 198.3 Requirements for Fire Rated Enclosures ............................................................... 198.3.1 Fire Rating ............................................................................................................................ 198.3.2 Doors .................................................................................................................................... 208.3.3 Ventilation ............................................................................................................................. 208.3.4 Cables ................................................................................................................................... 208.3.5 Fire Alarms and Fire Suppression Systems (where required) .............................................. 209 SCREENING OF SUBSTATIONS .............................................................. 2210 ELECTRICAL REQUIREMENTS AND RATINGS...................................... 2410.1 Electrical Protection of Substations ........................................................................ 2410.1.1 Requirement for a Contiguous Customer Switchboard ........................................................ 2410.2 Cables .................................................................................................................... 2510.2.1 Cable sizes ........................................................................................................................... 2510.2.2 Substations supplied from the Overhead Network ............................................................... 2610.2.3 Installation of Cable Ducts .................................................................................................... 2611 EARTHING REQUIREMENTS ................................................................... 2711.1 Design and Construction Objectives ...................................................................... 2711.2 Combined Earthing System.................................................................................... 2711.2.1 Connections to the Earth Terminal Bar................................................................................. 2811.2.2 Sizing of Earth Conductors ................................................................................................... 2811.2.3 Difficulty in getting the required Combined Earth Resistance .............................................. 2911.3 Separate MV and LV Earthing Systems ................................................................. 2911.4 Earth Electrodes and Connectors .......................................................................... 3011.4.1 Earth Electrodes ................................................................................................................... 3011.4.2 Earth Connectors .................................................................................................................. 3011.5 Conductive Structures in the Vicinity of Substations .............................................. 3111.6 Cases Requiring Detailed Earthing Design ............................................................ 3112 LIGHTING AND POWER ........................................................................... 3213 ENVIRONMENTAL REQUIREMENTS ....................................................... 3313.1 Oil Containment ..................................................................................................... 3313.1.1 Indoor Substations ................................................................................................................ 3313.1.2 MPS and Non MPS Substations Installed outdoors ............................................................. 3313.2 Noise ...................................................................................................................... 3313.2.1 Noise Regulations ................................................................................................................. 33




13.2.2 Compliance with the WA Noise Regulations ........................................................................ 3514 REVISION INFORMATION ........................................................................ 36




1 PURPOSE This document describes the technical requirements to be met where a new substation is to be installed or an existing substation is to be upgraded. In the hierarchy of documents pertaining to distribution substations, this document sits below the Distribution Design Manual Volume 3 Supply to Large Customer Installations and above the Distribution Substation Manuals, DSM-1 to DSM-9. This document shall also be read in conjunction with one of the following documents published by Horizon Power:

Underground Distribution Schemes Manual West Australian Distribution Connections Manual Western Australian Electrical Requirements (WAER) Supply Extension Projects General Conditions for Individual Customers

DSB 95/5.

2 APPLICATION All persons, including Horizon Power staff and contractors involved in the installation of substations for connection to Horizon Powers distribution network shall comply with these requirements, except as otherwise approved.

3 NORMATIVE REFERENCES The following documents contain provisions that, though referenced in the text, constitute requirements of these Substation Installation Technical Requirements, but not limited to these documents. At the time of publication, the editions indicated were valid. All standards and specifications are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the documents listed below. Information on currently valid national and international standards and specifications can be obtained from SAI Global.

3.1 Legislation and Standards AS/NZS 1170.0:2002 Structural Design Actions General Principles; AS/NZS 1668.1:1998 The use of Ventilation and Air Conditioning in

Buildings Fire and smoke control in multi compartment buildings;

AS/NZS 1680 Series - Interior and Workspace Lighting. AS 1682.1:1990 Fire Dampers Specification; AS 1905.1:2005 Components for the protection of openings in fire-resistant

walls Fire-resistant door sets;

AS 1940:2004 The Storage and Handling of Flammable and Combustible Liquids

AS 2067:2008 Switchgear assemblies and ancillary equipment for alternating voltages above 1 kV ;

AS 2419.1:2005 Fire Hydrant Installations- System design, installation and commissioning;

AS/NZS 3000 :2007 Wiring Rules published by Australian Standards;




AS 4799-2000 Installation of underground utility services and pipelines within railway boundaries;

Dial Before You Dig Service for lodging an enquiry and requesting a plan; Horizon Power Underground Distribution Schemes (UDS) Manual; Horizon Power FIPSM (Field Instruction Procedures & Standards Manual); Horizon Power Network Standard: Testing & Commissioning Technical

Requirements;

Western Australian Electrical Requirements - (WAER 2008) published by Energy Safety, WA;

Western Australian Distribution Connections Manual (WADCM 2012); Traffic Management for Works on Roads - Code of Practice, Main Roads,

WA

3.2 Definitions The definitions and abbreviations below apply:

Architect A qualified person who is engaged by the Customer to prepare drawings to comply with Uniform Building Bylaws and Local Government Authority requirements.

Cluster Substation A District or Sole Use substation where all equipment is clustered on a single site and where the installation of screening or an enclosure is at the Customers discretion.

Conductive structures

Shall include metallic and any reinforced or prestressed concrete parts of an installation.

Contiguous Applicable to Customers main switchboard location with respect to a Substation. Contiguous means adjoining or very close to the Substation enclosure to ensure that cable/s connecting the substation equipment to the main switchboard has zero probability of being damaged with consequent risk to safety and reliability. In the case of Sole Use Substations, contiguous means also visible means of isolation.

Customer Owned Substation

A substation where the Customer is on a Medium Voltage tariff and owns and is responsible for all electrical equipment other than Horizon Powers metering equipment and any medium voltage switches connecting the substation to the Horizon Power network.

Distribution System

Any apparatus, equipment, plant or buildings used, or to be used for, or in connection with, the transportation of electricity at a nominal voltage of less than 35 kV.

District Substation A substation that has LV connections to the street mains. Horizon Power owns and is responsible for all electrical equipment within the substation.




Electrical Consultant

A qualified person who is engaged by the Customer to design and prepare the electrical technical and regulatory documentation for the project.

Fire Rated A minimum fire rating Level of 120/120/120

Fire Resistant Surface

A surface having a fire rating Level of 120/120/120

Construction Project Manager

The Officer appointed by Horizon Power as Horizon Powers representative to whom all site contractual and technical matters are referred.

Gatic Cover Gas Air Tight Inspection Cover.

Guideline A set of recommendations indicating how something should be done or what sort of action should be taken in a particular circumstance.

MEN Multiple Earthed Neutral Installation

Low Voltage (LV) Low Voltage is defined as steady state voltages less than 1 kV

Medium Voltage (MV)

Steady state voltages equal to or greater than 1 kV and less than or equal to 35 kV

Modular Packaged Substation (MPS)

A District or Sole Use substation where the transformer and/or medium voltage switchgear and/or low voltage switchgear is housed in a self contained metal enclosure/s connected as a single package.

Policy A brief, straightforward statement indicating intention and direction, and enabling the decision-making process.

Procedure Prescribed means of accomplishing policy through a series of steps or processes

Site All parts of the works that are the subject of the offer and acceptance between Horizon Power and the Customer for the provision of electrical services.

Sole Use Substation

A substation established for a single customer and which has no LV interconnection with the street mains. Horizon Power owns and is responsible for all electrical equipment within the substation.

Structural Engineer

A qualified person who is engaged by the Customer to design and prepare structural documentation for the substation enclosure to resist loads and forces as outlined in AS 1170 where relevant.




Substation (Distribution Substation)

A collection of switchgear and/or a transformer/s on a single site (which may or may not be screened or enclosed) connected to the Distribution System.

Suitably qualified and competent engineer.

Professionally qualified electrical engineer with adequate experience to be competent in earthing design

WADCM Western Australian Distribution Connections Manual

WAER Western Australian Electrical Requirements

Works The electricity works associated with the provision of electrical supplies to the installation that is the subject of the offer




4 SUBSTATION INSTALLATION REQUIREMENTS

4.1 General All works shall be carried out in compliance with the following Horizon Power documented requirements and all works shall cease if the safety of workers or the public cannot be assured:

a) Training and Authorisation;

b) Job Planning and Risk Assessment (Work Planning);

c) Personal Protective Equipment (PPE);

d) Contractor Responsibilities;

e) Traffic Management; and

f) Related Instructions, Procedures and Standards (see Clause 2.2 below)

4.2 Instructions, Procedures and Standards Horizon Power and Service Providers shall comply with Horizon Power Instructions, Procedures, Standards and Construction Drawings when engaged in the installation of substations on Horizon Power networks.

This includes but not limited to the following Horizon Power documents:

a) Selected Horizon Power Field Instructions and Work Procedures;

b) Electrical Safety Standards (ESS);

c) Fit for Work Policy;

d) Minimum Personal Protective Clothing and Footwear Standard;

e) Job Risk Assessment Procedure;

f) Hazard Incident Reporting Notification and Investigation;

g) Guidelines for Excavation Work near Horizon Powers underground and

h) overhead electrical networks;

i) Project Flow and Quality Assurance Procedure for all work types;

j) Underground Cable Installation Manual;

k) Testing and Commissioning Standard; and

l) Distribution Equipment and Labelling Standard.




5 GENERAL CONCEPTS The standard substation types installed by Horizon Power are given below.

5.1 Types of Distribution Substations Horizon Power may require that the supply arrangement to an installation be via a particular "type" of substation, i.e.:

"District" Substation (With LV street feeds to/from the substation); "Sole Use" Substation (With no LV street feeds); or "Customer Owned" Substation (Supplied at distribution MV voltage levels). The decision as to which type is selected depends on several factors, including:

a) Size of customer's load;

b) Location of customer's load centre on the property, and distance of the same from the street boundary;

c) Type and nature of loads within the installation (disturbing, passive, etc.);

d) Nature of Horizon Power's existing distribution network and loading levels on other substations in the vicinity;

e) Horizon Power's need to connect LV street feeds to/from the substation; etc.

LV street feeds may be required to/from a substation for the following reasons:

a) The customer requires a "back-up" LV supply to the installation;

b) There will be future developments and load growth in the immediate area;

c) The customer's load is expected to increase in the future;

d) Ease of maintaining equipment in the substation (e.g. with street feeds into the substation, the customer's load can be partly met while the MV switchgear is being maintained); etc.

Consideration may also be given to installing a pad-mount or Integrated Package Substation (IPS) in lieu of the more common brick enclosure substations. There may be cost advantages as well as land/space advantages with this option.

5.2 Modular Packaged Substations (MPS) A Modular Package Substation comes complete with a single transformer and LV switchgear. It is housed in a self contained metal enclosure and is installed on an inverted, direct buried concrete culvert. If MV switchgear is required, this is also housed in a self-contained metal enclosure which is installed adjacent to the transformer on a direct buried steel mounting frame.

Modular Package Substations are used only as District Substations. They are not used as Sole Use substations. In addition, they are not fire rated and they are not designed for installation in a fire rated enclosure.

Therefore, MPS is the preferred arrangement for a District substation with a maximum load of 630 kVA after allowing for future load growth, and the substation does not require being fire rated.




5.3 Non MPS Arrangements A non MPS arrangement comprises a combination of one or more transformers plus LV switchgear and MV switchgear as required. Each of these items is a separate component housed in a self contained metal enclosure. The transformer is installed on an inverted, direct buried concrete culvert. The LV and MV switchgear enclosures are installed on direct buried steel mounting frames.

Non MPS components are not installed as a single package. They can be installed either as a cluster substation or in a fire rated enclosure (see Section 6). In the latter case, the culvert and switchgear mounting frames are not required.

Non MPS arrangements can comprise multiple transformers, with 1000 kVA being the largest individual transformer size. They can be used as both District and Sole Use substations.

A non MPS arrangement shall be used where;

A Sole Use substation is required; or Multiple transformers are required; or The maximum load is greater than 630 kVA after allowing for future load

growth; or

The substation requires being fire rated. 5.4 Customer Owned Substations

Typically, for loads greater than 4 MVA, a Customer Owned substation shall be provided. Neither the MPS nor the non MPS arrangements are suitable for Customer Owned Substations. Horizon Power shall provide extensible MV switchgear necessary for connection to the network. The equipment shall be installed in a switch room constructed by the customer, along with the customers own MV switchgear (See DSM-3-22 for details).

Where a customers load is less than 4 MVA, MV outdoor ground mounted switchgear can be considered. (See DSM-3-23 for details). A Customer Owned Outdoor Ground Mounted Substation cannot be upgraded for loads above 4 MVA. In the event that the customers load increases above 4 MVA, the substation shall be converted to a MV Indoor Ground Mounted Substation, which will require a switch room to be built.

In areas with overhead networks only, MV outdoor aerial mounted switchgear may be used (See DSM-3-24 for details).




6 MINIMUM REQUIREMENTS FOR SUBSTATION INSTALLATIONS

6.1 Access

6.1.1 Substation Site Access Access to the substation site shall be suitable for heavy vehicles to enable the construction, maintenance and operation of the substation. The maximum allowable slope of the access road / driveway to the substation is 1:10. It is essential that the immediate area around the substation is level to facilitate removal or replacement of the transformer/switchgear.

6.1.2 Substation GATIC Cover Access GATIC covers provide access from the top, when a substation is in an underground location (e.g. building car parks) to facilitate installation and removal of equipment.

If Gatic covers are to be installed:

a) And access to the substation is via gatic cover, the clear opening dimensions shall to be 2500 mm x 2000 mm.

b) Inside the substation building, the minimum clear ceiling height above the gatic cover shall be 3.3 m. Lifting eyes or a monorail shall be designed and installed to allow for the installation of Horizon Power plant. See Horizon Power drawing DSM-6-05 for details.

c) Outside the substation building, there shall be access for a crane from the street or right of way with no obstructions above the gatic cover.

6.1.3 Equipment Access to the substation shall be suitable for heavy plant. If a transformer is to be installed, consideration shall be given to installation constraints (i.e. size and weight). The general dimensions of a 1000 kVA, 33 kV transformer are, 1600 mm high x 2100 mm wide x 1800 mm long, with a mass of 5 tonnes. Equipment foundations shall be capable of holding the loads of all equipment to be installed.

The method of lowering or raising large items of equipment shall be considered at the design stage.

6.1.4 Personnel Access Horizon Power shall be provided direct access to all substations, 24 hours per day, 7 days per week. This is required even where the substation is located within a building or more than 30 metres from a property boundary.

6.1.5 Location from Street Front District substations shall be located not more than 30 m from the street boundary to limit voltage drop.




6.2 Site Requirements and Preparation There are a range of variables that may impact on the finished ground levels around a substation site including but not limited to the following geographical, environmental and climatic factors:

a) Soil types, content, compaction and stabilisation;

b) Position of the site in terms of elevation above flood levels and location in relation to coastal or inland environments;

c) Weather conditions including ambient temperature and levels of precipitation;

d) Drainage;

e) The existence of or use of existing or introduced vegetation/natural ground cover;

f) The use or need for retaining walls; and

g) The size and overall weight of the structure in terms of the prevailing ground conditions.

The following conditions shall apply to all substation sites:

a) The site shall not be lower than the finished level of surrounding lots and adjacent road carriageways. In rural areas, the finished level of carriageways may be higher than the surrounding areas to allow for natural drainage from the carriageway;

b) Substations shall not be built in water courses and shall be located 1 metre above the 100 year flood level, pegged, compacted and levelled to an out of plane tolerance of 10 mm. ( In certain locations, where the built up area is below the 100 year flood level, pad-mount substations may not be suitable);

c) No other services including telecommunications, water and gas services shall be installed either on or under or in close proximity to the site;

d) The site shall be suitably prepared and the ground stabilised by the removal of any vegetation and a layer of top soil to the depth of 100 mm and then backfilling with a layer of sand. If the site contains materials other than sand (e.g. rock, clay or building materials) the site shall be excavated and back filled with clean compacted sand to a depth of 1 metre;

e) The site shall be compacted to a blow count of 8 per 300 mm using a Standard Penetrometer or a Perth Penetrometer.

f) In the event that the site is higher than the finished levels of neighbouring areas, retaining walls, access steps and drainage complying with the relevant Australian Standards and the requirements of the Local Government Authority shall be provided;

g) If batters are required, they shall be provided with a finish that prevents wind and water erosion, including kerbing or similar low profile retaining structures around the lower edge to maintain batter material. Where retaining walls, access steps, screens and /or batters are installed, the land requirements shall be increased to accommodate these associated features and any associated footings. Footings for such structures, or adjacent properties shall not encroach into the substation area;




h) Where a substation is located in a trafficable area such as car parks, there is a likelihood of vehicles damaging or blocking access to the substation. In such situations bollards, concrete kerbing or other protective structures shall be installed to protect the substation and maintain the ability to operate equipment safely. Bollards with a non-conductive surface are preferred, to prevent touch voltage hazards. (see Clause 9.5 when installing conductive bollards). Concrete kerbing shall be 150 mm high with a barrier profile around the site boundary;

i) Following the installation of all substation equipment, exposed surface areas at the site shall be stabilised to mitigate against the effects of erosion. Crushed limestone or blue metal (10 -25 mm aggregate) shall be laid around each item of equipment to a depth of 50 mm and to a width not exceeding 450 mm. Any such laid materials shall be easily removable to allow access to cables and equipment and shall be clear of the earth grading ring by a minimum of 300 mm;

j) AS 2419.1:2005 Fire Hydrant Installation requirements are that fire hydrants and brigade booster assemblies be located in a position at least 10 metres from any substation;

k) Substations shall be located away from noise sensitive premises as per Section 13; and

l) Based on conservative worse case scenarios, a minimum 8 m clearance from petroleum/gas storage or dispensing facilities (refer to WADCM Clause 14.4.2.4 for more details).

Refer to DSM-3 for minimum land area requirements.

6.2.1 Sole Use and Customer Owned Substations A suitable site and building shall be provided by the customer in accordance with the conditions stipulated in Clauses 6.2 and 6.3, at no cost to Horizon Power.

The customer shall provide architectural drawings of the proposed site, including areas adjacent to it, for approval by Horizon Power, prior to commencing construction of the substation.

The entire area as shown in drawings approved by Horizon Power shall be retained for Horizon Powers sole use, unhindered by any obstructions that may affect normal operations and maintenance.

6.3 Requirements for Buildings As a minimum, substation buildings shall comply with the requirements of the Building Code of Australia and with the requirements of the Local Government Authority of the area in which the substation is to be located. Structural design shall be in accordance with AS/NZS 1170 series of standards.

6.3.1 General Requirements a) Load carrying structural members, partition walls, claddings, enclosures

etc, shall be selected to achieve the appropriate fire rating;

b) Electrical operating areas shall be designed to prevent water ingress and to minimise condensation;




c) Materials used for walls, ceilings and floors on the ground shall not be damaged by water penetration or leakage;

d) All penetrations shall be sealed with a fire rated material;

e) The building design including foundations shall take into account the expected mechanical loading (weight of transformers and other equipment) and internal pressure caused by an arc fault;

f) The design strength of the building shall be sufficient to withstand all static and dynamic loads due to normal operation of the installation and abnormal conditions associated with equipment failure, not limited to but including internal pressure caused by an arc fault or oil vapour explosion;

g) Floors shall be flat and stable and able to support the static and dynamic loads;

h) Ceilings shall be a minimum height of 2.5 m above floor level;

i) The external walls and roof of the building shall have sufficient design strength for the environmental conditions (rain, wind, sun etc.); and

j) An outdoor substation shall comply with the fire protection requirements in Clause 8.1. If these requirements cannot be met, an indoor substation shall be considered.

Fire protection of Indoor substations shall be as per Clause 8.2.

6.3.2 Aisles and Escape routes a) Aisles shall be at least 750 mm wide and shall not be reduced even where

equipment projects into aisles;

b) Space for evacuation shall be 600 mm (minimum), even when removable parts or open doors, which are blocked in the direction of escape, intrude into escape routes; and

c) There shall be at least two points for egress.

6.3.3 Doors a) Access doors shall be secured to prevent unauthorised access;

b) Access doors shall open outwards and be provided with safety signs in accordance with HPC-2AA-07-0001-2012: Guideline - General Application of Signs Used on Distribution Equipment;

c) Doors shall be positioned such that they do not create a personnel hazard or allow blockage by parked vehicles;

d) Emergency exit doors shall have panic release bars fitted to facilitate opening in an emergency from the inside, even when they are locked from the outside;

e) The minimum dimension of doors shall be 2040 mm high and 820 mm wide for single doors and 2040 mm high and 1720 mm wide for double doors.

6.3.4 Ventilation Ventilation is required to assist air circulation and help cool transformers. The preferred method for aerating fully enclosed substations is by natural cross flow ventilation. This methodology minimises the risk of transformer or equipment




failure caused by overheating due to mechanical and electrical malfunction of installed ventilation systems.

Adequate openings shall be provided for ventilation and pressure relief for gaseous products to prevent structural damage in the event of an explosion in roofed enclosures. In substations where a transformer is installed, the normal transformer ventilation will meet this requirement.

Where natural cross flow ventilation for transformers cannot be achieved, and forced draught ventilation is required, fans, ducting and weather proof outlet grilles shall be installed. Individual ducts are required for each transformer and grilles shall be of robust construction and with low resistance to air flow. Refer to DSM-6-02 for exhaust fan details and DSM-06-03 for the associated sub distribution board schematic.

If the ducting passes over the top of the transformer, the ceiling height of the enclosure shall be increased to a minimum of 3 metres.

6.3.5 Cable Trenches Trenches shall be 1200 mm x 1200 mm with trench walls and floors painted with Silicon Glaze S50 waterproof paint. Trench covers shall be steel grated with Webforce C253MP or equivalent (Refer to DSM-6-10 and DSM-3).

Access to trench from the outside shall be via conduits only. Once cables have been installed, conduits shall be completely sealed with fire retardant material (Refer to DSM-6-01).




7 POINT OF SUPPLY The customer shall provide and install the consumer mains cable from the customers main switchboard to Horizon Powers designated point of supply.

These cables shall:

a) Take the shortest possible route across Horizon Powers site;

b) Not cross underneath any Horizon Power equipment;

c) Be installed in Heavy Duty PVC conduits; and

d) Preferably be copper cables due to the smaller lug sizes.

Consumer mains including neutral conductors, switchboards, main switches and service protective devices shall comply with the WA Electrical Requirements (WAER), WADCM and AS/NZS 3000.

7.1 District and Sole Substations Where the point of attachment is within a District or Sole Use substation, the Consumers Mains shall connect the Customers Main Switchboard to:

Horizon Powers LV switchboard in a District substation; and Horizon Powers transformer LV terminals in a Sole Use substation. The maximum size of consumer mains that can be terminated within a District or Sole Use Substation is shown in DSM-1.

7.2 Customer Owned Substations The Customer shall supply and install adequately rated medium voltage main switches and busbars suitable for connection to Horizon Powers MV metering unit/s. Although the use of switchgear identical with Horizon Powers is preferred, Customers may purchase and install switchgear of a different make. In such cases, to enable connection of the Customers switchgear to Horizon Powers switchgear, the Customer shall provide a suitable arrangement acceptable to Horizon Power. The type of switchgear Horizon Power uses will be advised on application (see DSM-3-22A/22B).

If a recloser is used by the customer as the main switch, it must be set to one shot to lock out operation (see DSM-1-10 and DSM-3-24 for details).

To ensure the integrity of Horizon Power and Customer equipment and the safety of operators, such an arrangement shall be designed and constructed with adequate clearances, rating, etc and verified by type testing in accordance with the relevant Australian Standard.




8 FIRE PROTECTION OF SUBSTATIONS Transformers used in Horizon Powers substations have a potential fire risk zone that extends in every direction and fire protection requirements are outlined below.

8.1 MPs and Non MPS Substations installed outdoors Minimum separation requirements are given in Table 1.

Table 1: - Minimum Separation Distance Substations Installed Outdoors

Transformer Capacity Clearance to other similar capacity transformers or Fire Resistant Surfaces

Clearance to Non Fire Rated building surfaces

Up to 630 kVA

(< 1000 L oil)

1 m 6 m

630 kVA (> 1000 L oil) 3 m 7.5 m

Substation enclosures not fully enclosed, with open roof, shall maintain clearance to non fire rated building surfaces in accordance with Table 1. (See details in DSM-5).

8.2 Substations Installed Indoors (Including Customer Owned Substation) All Substations installed indoors (inside buildings) shall be fire rated to a FRL not less than 120/120/120. This applies if the Substation building houses a single transformer rated lower than 630 kVA or contains several transformers with capacity 630 kVA or greater.

Where there are more than two transformers, transformer pairs shall be fire segregated to a FRL not less than 120/120/120.

8.3 Requirements for Fire Rated Enclosures This clause describes the additional conditions to those specified in Clause 6.3 where the substation requires being fire rated.

8.3.1 Fire Rating Fire rated enclosures such as Indoor substations shall be fire rated, with a minimum FRL 120/120/120 fire rating.

FRL 120/120/120 fire rated walls are deemed to comply if they constructed in accordance with AS 3700 as follows:

(a) Double clay brick on a concrete footing; or

(b) 150 mm thick solid concrete blocks.

Reinforced concrete floors and roofs/ceilings shall be built to be not less than 100 mm thick at the point of minimum cross section in order to achieve a FRL 120/120/120 fire rating.




8.3.2 Doors Fire rated enclosures such as Indoor substations shall be fitted with self-closing fire doors having a FRL not less than 120/120/120 when;

(a) An enclosure door opens to any part of a building; or

(b) Where there is any other structure within its fire risk zone (see DSM-5-02 DSM-5-04 and DSM-5-05 for details).

Fire resistant doors shall be fitted with panic release bars, complying with AS 1905.

8.3.3 Ventilation Ventilation and pressure relief device openings in indoor substations shall be fitted with self closing dampers having a FRL not less than 120/120/120 when:

(a) Fire exits or areas set aside for fire escape purposes are within 6 m of such openings (although there shall be no opening to a fire isolated stairwell); or

(b) An opening is not more than 2 m from any other part of a building housing the substation or any other adjacent building.

(See DSM-5-04 and DSM-5-05 for details).

The requirement of the fitting of self-closing dampers will not apply when ventilation ducts of a suitable length are installed external to the enclosure and such ducts have a FRL not less than 120/120/120. For details of fire rated dampers refer to AS 1682 and AS/NZS 1668.

For substations where only switchgear is installed, pressure relief vent/s shall be installed and all vents shall be fitted with external louvers for security. Fire dampened vents shall be installed as shown in DSM-6-02. They shall be fitted with rotating type blades held in the open position by two thermal links in parallel and shall conform to AS 1682 and AS/NZS 1668.

8.3.4 Cables Cables located within a building and supplying an indoor substation shall be enclosed or otherwise protected by an enclosure constructed to an FRL of not less than 120/120/120.

Cables in trenches and buildings shall be laid in such a way that the fire safety of the building is not adversely affected. Trench covers shall not exceed 1 metre in length and shall be steel grated with Webforce C253MP or equivalent (Refer to DSM-6-10 and DSM-3). To avoid fire propagation, ducts through which cables pass from one room to another shall be sealed with suitably fire resistant (minimum 2 hrs) material.

Power and control circuits shall be physically separated or routed differently to preserve the integrity of control circuits for as long as possible following possible damage to power circuits.

(Refer to DSM-6 and DSM-3)

8.3.5 Fire Alarms and Fire Suppression Systems (where required) For substations installed within buildings, there may a need to specify fire alarms and automatic fire suppression protection. Local authority requirements in this regard vary and these need to be verified.




Fire alarm systems shall be dual activation systems including both thermal (rate of rise detectors) and smoke detectors.

Fire suppression systems shall be capable of containing the fire and be of the sprinkler type with foam (dry head). Water sprinklers are not permitted. The foam released shall not damage equipment within the substation or interfere with their operation.

In addition to the requirements of clause 8.3.1, automatic fire suppression protection should be considered when transformers with capacity 630 kVA or more are installed.




9 SCREENING OF SUBSTATIONS Where a MPS or non MPS cluster arrangement is to be installed, Horizon Power has no requirement for screening around the site. However, the Customer may elect to install screening around the site (e.g. for aesthetic reasons). The erection of such screening is at the Customers discretion and is the Customers responsibility.

If the Customer proposes to install screening, this shall be stated in the Customers application to Horizon Power. The following conditions relating to screening shall apply:

a) In general, any type of screening is permissible (e.g. vegetation, fencing, masonry walls, etc.). Horizon Power will provide a drawing showing indicative permissible screening arrangements for the site. (see DSM 6-13);

b) Screening shall comply with the separation requirements in Table 1. (Clause 6.1.1);

c) Where full screening is proposed, two openings are required with dimensions as shown on the Horizon Power drawings. The openings do not require doors. However, if the Customer elects to install doors at these openings, the doors are to be hinged to open both inwards and outwards, with no self locking. The outward opening of the doors shall be unobstructed with no physical barriers within a 2 metre radius of an opened door. If locking is required, Horizon Power padlocks are to be used. These are available from the Construction Project Manager for the project. Doors do not need to be fitted with labels;

d) Where screening is to be roofed, liaison with Horizon Power is required to ensure issues such as ventilation and future equipment removal/replacement are addressed;

e) The screening shall be installed only after Horizon Power has completed all work on site. This is to ensure that the screening does not interfere with installation work nor become undermined by any Horizon Power trench excavation;

f) No part of the screening or associated foundations or supports shall intrude within the Horizon Power site area as shown on the appropriate drawing. The Customer shall be responsible for ongoing maintenance of the screening;

g) Unless specifically negotiated otherwise with Horizon Power, the screening and any associated foundations or supports shall not extend more than 550 mm below finished ground level. This is to protect Horizon Power cables entering and exiting the site;

h) The use of metallic screen fencing is not recommended.

i) Where metallic screening is installed within the 2 metre restricted zone (DSM-6-13) it shall be bonded by suitable earthing connections to the substation earthing system. In addition, it shall be connected to a grading wire buried at a depth not less than 500 mm below ground and not more than 550 mm below ground at a distance of 1000 mm outside the screening; and




j) Metallic screens installed outside the 2 metre restricted zone (DSM-6-13) may not need to be bonded to the substation earthing system or grading ring (earthing designs and calculations may show that they need to be bonded).

k) Horizon Power reserves the right to remove a screen, if required, when it has to work on a substation.




10 ELECTRICAL REQUIREMENTS AND RATINGS Equipment installed in substations including protective devices and cables shall have the capability to withstand, without damage, the maximum fault currents at the substation location. Fault level drops when a substation is located farther away from the source of supply, (e.g. a generating station).

System design fault levels may be more or less than typical values shown in Table 2. The maximum system design fault level for any particular location must be obtained from Horizon Power. LV fault levels will depend on the number of transformers used to supply the installation.

Table 2: - Typical MV System Design Fault Levels (1 second)

SYSTEM VOLTAGE

(kV)

SYSTEM DESIGN FAULT LEVEL

(MVA) (kA)

6.6 200 18.1

11 350 18.1

22 500 13.1

33 750 13.1

10.1 Electrical Protection of Substations Protective devices shall be installed in substations to ensure that:

faults are safely disconnected; and discrimination is provided to prevent fault impact on network and

customers.

Suitably rated fuses and circuit breakers shall be used to achieve this objective.

The ratings, length and exposure to damage of cables downstream of protective devices shall be considered, to ensure that cables are adequately protected. Other downstream protective devices such as customers main switch shall grade with substation fuses.

Details of fuses and circuit breakers are provided in DSM-1 - Customer Supply Arrangements. Where circuit breakers are specified, they shall be of the current limiting type.

10.1.1 Requirement for a Contiguous Customer Switchboard Where a customer is supplied from a fused low voltage circuit emanating from a District Substation, the customers switchboard can be remote from the substation. In such case, the consumers mains is protected by a fuse that grades with the customers main switch, which is dependent on the customers load. This is not always possible because the maximum fuse size on the low voltage circuit depends on the transformer rating/voltage and may also depend




on whether the transformer is protected by a drop out fuse or RMU fuse switch. (DSM-1-02, DSM-1-03, DSM-1-04).

Where a customer is supplied from a District Substation and the magnitude of the load is such that the customers main switch cannot grade with the maximum size LV fuse which can be used with the transformer, the customer shall be supplied either via LV links or LV disconnects. In such case, the customers switchboard shall be contiguous with the substation. (DSM-1-05, DSM-1-06).

Where a customer is supplied from a Sole Use Substation and consumers mains is connected directly on to the low voltage bushing of the transformer with no protection, the customers main switchboard shall be contiguous with the substation, to limit the amount of unprotected cable that may be exposed to damage. (DSM-1-07, DSM-1-08, DSM-1-09).

Where the requirement for a contiguous customer switchboard exists as per above and where:

(a) The substation is screened, the customers main switchboard shall be against the exterior of the screen.

(b) There is a substation enclosure constructed, the customers main switchboard shall be against the exterior wall of the enclosure.

(c) There is no screen or enclosure, the customers main switchboard shall be immediately adjacent to the edge of the substation site boundary but not more than 1 metre from the point of supply.

10.2 Cables Cables to be used in substation installations shall:

a) Be capable of carrying the maximum load currents and fault currents expected during the life (65 years) of the cable without mechanical damage or chemical deterioration;

b) Be Installed such that the possibility of inadvertent mechanical damage and interference is minimised;

c) Have insulation appropriate for the nominal voltage;

d) Have termite protection;

e) Have safe separation clearance from other cables and services; and

f) Have appropriate mechanical protection when laid below ground and when located above ground, up to a height of 2400 mm from any surface on which a person can stand to the point where the cable enters the ground.

10.2.1 Cable sizes Standard cable sizes used are given in Table 3.

Table 3: - Standard Cable Sizes

LV 22 kV 33 kV

16, 25, 185, 240, 630 mm2 35, 185, 240, 400 mm2 50, 95, 185 mm2




3.3 kV, 6.6 kV and 11 kV installations shall be equipped with 22 kV cables.

Refer to HPC-5DJ-03-0001-2012: Standard - Underground Cable Installation-Technical Requirements, for details about installing cables associated with substations.

10.2.2 Substations supplied from the Overhead Network Substations supplied from the overhead network via drop out fuses shall be through an appropriate cable termination installed on a pole.

10.2.3 Installation of Cable Ducts Cable ducts shall be installed during civil construction of substations to facilitate cable installation at a later stage. Installation details for cable ducts associated with substations are provided in DSM-6-01 and DSM-6-02.




11 EARTHING REQUIREMENTS

11.1 Design and Construction Objectives The design and construction of the earthing system shall ensure that:

a) All conductive parts consisting of metalwork and equipment that is within the reach of a person standing on the ground (i.e. up to 2.4 m above ground) are effectively earthed;

b) Hazardous touch, step and transfer voltages that can occur during fault conditions are mitigated;

c) A low impedance earth is available to effectively carry to earth transient currents that are imposed due to lightning and switching surges; and

d) Future modifications, particularly below ground require minimal alteration.

Earth conductors, electrodes and connections (joints) shall be designed and constructed to ensure that:

a) Fault currents are carried to earth without damage to these components;

b) Possibility of inadvertent mechanical damage and interference is minimised; and

c) Corrosion is minimised.

11.2 Combined Earthing System For distribution substations, a combined earthing system shall be used, where the MV and LV earthing systems are interconnected at an earth terminal bar (DSM-6-11 and DSM-6-12) or a grading ring. Details of earthing connections are provided in DSM-6. The combined earthing system shall have a resistance sufficiently low ( 1 ohm) to ensure that the design objectives of Clause 11.1 are fulfilled.

A grading ring shall be installed in substation installations to mitigate against touch voltages. The grading ring is installed around equipment that is earthed and subject to hazardous voltage rise during fault conditions. It is installed around the substation at a distance of 750 mm (with substation doors open) and buried at a depth of 500 mm. The grading ring is connected to two earth electrodes which are installed diagonally at opposite ends, which makes up the earthing system.

Two electrodes shall be used to ensure that there is adequate redundancy in the event that one electrode is disconnected from the grading ring for some reason including testing. A maximum resistance of 10 ohms per electrode is permitted to allow for upstream protection to operate correctly.




11.2.1 Connections to the Earth Terminal Bar The following shall be connected to the earth terminal bar separately using appropriately sized conductors:

a) Metallic substation enclosure (able sized to greater of MV or LV fault current);

b) Metallic MV switchgear frame (cable sized to MV fault current);

c) MV surge diverters (if any - cable sized to MV fault current);

d) Metallic sheath of MV cables (cable sized to MV fault current);

e) Transformer earth lug (cable sized to greater of MV or LV fault current);

f) Transformer neutral (cable sized to LV fault current);

g) Earth bar of LV switchboard (cable sized to LV fault current);

h) Grading ring to earth terminal bar (cable sized to MV fault current);

i) Earth electrode system (if present);

j) Metallic substation doors; and

k) Steel reinforcement in substation structures (if present).

In MPS and non MPS substations, the MV and LV earth bars are permanently connected (factory fitted) by a link. This allows the MV and LV earths to be separated if required. Also, on the LV side, the neutral bar and earth bar are connected by a solid link.

11.2.2 Sizing of Earth Conductors The conductors referred to in a) to g) of Clause 11.2.1 shall be sized such that they are not smaller than those values given in Table 4.

Table 4: - Size of Earth Conductor

Expected Earth Fault Current (MV or LV) at Substation during Substation Life

PVC Insulated Single core copper conductor

For a) to h) of Clause 9.2.1

9.5 kA for 1 sec 70 mm2 >9.5 kA and 18 kA for 1 sec

150 mm2

or 2 x 70 mm2

>18 kA and 30 kA for 1 sec

3 x 70 mm2


2 x 150 mm2

or 4 x 70 mm2

>40 kA for 1 sec Determine size as per AS 2067:2008




The grading ring shall be connected to the earth terminal bar by two separate PVC Insulated conductors sized in accordance with Table 4. Size of grading ring conductor shall be as per Table 5.

Table 5: - Size of Grading Ring Conductor

Expected Earth Fault Current (MV or LV) at Substation during Substation Life

Bare copper conductor

12 kA for 1 sec 70 mm2 >12 kA and 25 kA for 1 sec

150 mm2

or 2 x 70 mm2


2 x 150 mm2

or 4 x 70 mm2

>40 kA for 1 sec Determine size as per AS 2067:2008

11.2.3 Difficulty in getting the required Combined Earth Resistance The number of customer installation electrodes associated with the LV MEN system connected to the substation will influence the combined resistance. Where there are an insufficient number of customers connected, it may be difficult to get a combined resistance of less than 1 ohm.

Low resistance earths can be installed at pillars located away from the substation, where the soil resistivity may be conducive to obtaining a low resistance earth and may also be beyond the zone of influence of the substation earth. For example, deep earths (typically 30 m) where there is a lower resistivity layer deep into the earth.

11.3 Separate MV and LV Earthing Systems Where a common earthing configuration does not provide for safe touch, step and transfer voltages, segregation of MV and LV earthing systems shall be considered, but this is not the preferred option. A separate earthing system shall require a detailed earthing design to be carried out by a suitably qualified and competent engineer.

By separating the MV and LV electrodes, the transfer of EPR from the MV system to the LV system can be controlled. However, the integrity of the separated MV and LV earthing systems must be maintained during the life of the installation. Therefore, they shall be captured in Horizon Powers Geospatial Information system (GIS). This will ensure that the possibility of other earthed structures being installed within the physical separation distance will be minimised.




A minimum separation distance of 4 m has been suggested in AS 2067. The required separation may need to be much larger for low/high resistivity layers with a LV network of limited extent. (Refer also to Clause 9.6)

Separated MV and LV earthing systems may not be effective in controlling hazardous step and touch voltages in the event of a MV line to LV line contact at the distribution transformer, or on a conjoint MV/LV line section. The following options may be considered for protecting against MV to LV contacts:

Ensuring the configuration of LV lines at the distribution transformer poles is such that MV to LV contact is unlikely; and

Replacing bare LV conductors over conjoint MV/LV spans with LV buried cable and LV ABC cable.

The transformer insulation level shall be rated to withstand the maximum EPR on the MV earthing system, without breaking down to the LV side (e.g. via MV/LV winding breakdown, or transformer tank to LV winding breakdown).

When the LV earthing system is segregated from the MV earthing system at a distribution substation, the total earth impedance of the LV earthing system (including associated MEN earths) shall be sufficiently low to ensure that the MV feeder protection will operate in the event of a MV winding to LV winding fault.

11.4 Earth Electrodes and Connectors

11.4.1 Earth Electrodes Copper clad steel rods (15 mm diameter, 1.4 m length) are used as standard on the Horizon Power network for earthing. The rod is driven so that its top is 200 mm below surface level which provides adequate protective cover rod and the cable connected to it and to minimise the effect of seasonal variation in the upper layers of soil.

When joining earth electrodes vertically by driving earth electrodes into the ground, the electrodes must be installed in drilled holes or mechanically driven to minimise vibration and ensure good electrode to ground contact. Electrodes must never be cut.

In rocky areas, driving earth rods mechanically may cause them to break. In such cases bored earths shall be installed by boring a hole in the ground to the required depth. Earth rods are then lowered into the hole and backfilled with a suitable earthing enhancing material (e.g., gypsum). When joining electrodes with couplings proper electrical connectivity shall be maintained by suitable means such as scratch brushing and greasing.

More details about earthing electrode installation can be found in the Distribution Line Earthing Standard: HPC-9DC-08-0001-2012.

11.4.2 Earth Connectors a) Connectors used must be either of the bolted or compression types;

b) Normally accessible earthing terminations to equipment must be made with compression lugs or bolted clamps;




c) All earthing connections to equipment and electrodes shall be so arranged that they can be removed, permanently or temporarily, independently of any other earth, so as not to compromise safety; and

d) All services including water, sanitary drainage and gas shall maintain a minimum separation and exclusion zone of 500 mm around LV earth electrodes. This zone shall be extended to 600 mm for stormwater drainage services. (WADCM Clause 12.5.5.3.)

11.5 Conductive Structures in the Vicinity of Substations An Earthing design must take into consideration the close proximity of continuous metallic objects that can give rise to transferred voltages. Transferred voltage is the potential rise of an earthing system caused by a current to earth transferred by means of a connected conductor (for example, a metallic cable sheath, metallic pipelines, metallic fences or rail) into areas with low or no potential rise relative to earth, resulting in potential difference occurring between the connected conductor and its surroundings.

When the potential rise on the earthing system is transferred by metallic pipes (water or gas), or a fence earthed at regular intervals along its length, such conductive parts will rise to a potential somewhere between the maximum and minimum potential rise affecting it.

Such conductive structures shall be separated from the substation earth grading ring by at least 2 metres. Metal bollards installed outside substations shall be located at least 2 metres away from the earth grading ring. If located within 2 metres, the bollard shall be bonded to the grading ring and included within the grading ring.

Telecommunications plant, gas pipelines and metallic fences can be subject to transfer voltages from substation installations. Refer to the Standard Power Lines and Cables in the Vicinity of Conductive Installations: HPC-9DC-07-0001-2012, which provides guidance on calculating the EPR and LFI (Low Frequency Induction) on such conductive structures.

11.6 Cases Requiring Detailed Earthing Design The following are some cases where detailed earthing design must be undertaken as they are likely to result in unacceptable earthing:

a) MEN systems where there is a small number of MEN connections (i.e. less than 100 interconnected neutrals within a circular radius of 1 km);

b) Commercial centres with no LV interconnections;

c) Close proximity to swimming pools;

d) Close proximity to Telecommunication pits;

e) Close proximity to Rail traction corridors;




12 LIGHTING AND POWER Accessible indoor and outdoor substations shall be provided with suitable lighting for routine operations.

Lighting levels required shall be considered during substation design. Guidance on lighting levels is provided in the AS/NZS 1680 Series - Interior and Workspace Lighting.

Lighting and Power circuits and outlets in substations shall be wired in accordance with AS 3000.

In District Substations, Horizon Power shall supply and install all lighting fixtures, GPOs and wiring necessary.

In Sole Use and Customer owned Substations, the customer shall be responsible for the above as Horizon Power has no LV supply within the substation. Where the installation of a fan is required for ventilation, a suitable GPO shall be provided.

Refer to DSM-06-03 for typical Indoor Substation Distribution Board.




13 ENVIRONMENTAL REQUIREMENTS

13.1 Oil Containment

13.1.1 Indoor Substations Indoor substations shall have provision for the containment of oil in transformers by the erection of a suitable bund. A 2-course bund built of 230 x 100 x 76 mm standard bricks shall suffice.

Other proven oil containment / absorption options such as using hydrocarbon absorbents are acceptable, although oil bunds have been Horizon Powers standard practice.

All probable oil leakage points including cable entry points shall be suitably sealed to prevent oil leakage.

13.1.2 MPS and Non MPS Substations Installed outdoors Horizon Powers standard practice does not require oil containment in transformers installed outdoors.

Substations shall not be installed in environmentally sensitive sites, without adequate oil containment facilities. This can be in the form of in-built oil holding trays, oil bunds or other proven containment / absorption options such as using hydrocarbon absorbents (Refer to DSM-9).

13.2 Noise

13.2.1 Noise Regulations Noise limits are generally set by the Department of Environment and Conservation (DEC) in Western Australia through Environmental Protection (Noise) Regulations 1997.

The Noise Regulations define Noise Sensitive Premises as:

a) Premises occupied solely or mainly for residential or accommodation purposes;

b) Rural premises

c) Caravan parks and camping grounds;

d) Hospitals with less than 150 beds;

e) Rehabilitation centres, care institutions and the like;

f) Educational institutions;

g) Premises used for public worship;

h) Hotels which provide accommodation to the public;

i) Premises used for aged care or child care;

j) Prisons and detention centres; and

k) Any other promises not defined as industrial, utility or commercial premises as per the Noise Regulations.




The noise level limits for Noise Sensitive Premises are given in Table 6.

Table 6 Noise Level Limits for Noise Sensitive Premises

Location of Substation Assigned level (dB)

Within 15 m from Noise Sensitive Premises

45 +Road Noise Level

Beyond 15 m from Noise Sensitive Premises

60 +Road Noise Level

Beyond 450 m from Noise Sensitive Premises

0

Road Noise Level is determined as follows:

1. Major Road (more than 15,000 vehicles per day) within 100 m of Noise Sensitive Premises = 6 dB

2. Major Road (more than 15,000 vehicles per day) beyond 100 m of Noise Sensitive Premises = 2 dB

3. Secondary Road (6,000 - 15,000 vehicles per day) within 100 m of Noise Sensitive Premises = 2 dB

4. Secondary Road (6,000 - 15,000 vehicles per day) beyond 100 m of Noise Sensitive Premises = 1 dB

5. Any other Road or any Road beyond 450 m from noise Sensitive Premises = 0 dB

Horizon Power Transformers are designed to emit sound levels in accordance with AS 2374.6 and the maximum levels are given in Table 7.

Table 7 Maximum Transformer Sound Levels

Transformer Capacity Sound level (dB)

1000 kVA 65 dB

630 kVA 63 dB

315 kVA 58.5 dB

200 kVA 56 dB




13.2.2 Compliance with the WA Noise Regulations To comply with the WA Noise Regulations, the Noise Level Limits for Noise Sensitive Premises should not be exceeded. Where compliance is not achieved by transformer location with respect to the concerned Noise Sensitive Premises, the following options may be considered:

a) Using sound attenuating enclosures or barriers; and

b) Providing sufficient clearance to noise sensitive premises.

In the design of substations the following shall be considered:

a) Impact on the local environment (Regulations/Guidelines);

b) Impact on the working environment (Occupational Health & Safety Regulations in WA); and

c) Equipment Noise (from Horizon Powers Transformer Specification and in accordance with AS 2374.6 for transformers).

Refer to DSM-6-09 for setback requirements from sensitive premises.




14 REVISION INFORMATION (Informative) Horizon Power has endeavoured to provide standards of the highest quality and would appreciate notification if any errors are found or even any queries raised.

Each Standard makes use of its own comment sheet which is maintain throughout the life of the standard, which lists all comments made by stakeholders regarding the standard.

The following comment sheet DM: 3553660 can be used to record any errors or queries found in or pertaining to this standard, which will then be addressed whenever the standard gets reviewed.

Date Rev No. Notes

15/04/2013 0 Original Issue

2013-09-16T12:36:24+0800Anthony Seneviratne

2013-09-17T10:30:19+0800Justin Murphy

2013-09-17T10:30:59+0800Justin Murphy

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