DIRECTLINK NETWORK MANAGEMENT PLAN Directlink Joint Venture Version 3.0 23 May 2013
TABLE OF CONTENTS 1. INTRODUCTION... 1 1.1 GENERAL... 1 1.2 OBJECTIVE OF NETWORK MANAGEMENT PLAN... 1 1.3 STRUCTURE OF THE PLAN... 1 1.4 REFERENCES... 2 2. DIRECTLINK TRANSMISSION SYSTEM... 4 2.1 OVERVIEW OF DIRECTLINK JOINT VENTURE... 4 2.2 ORGANISATIONAL ROLE AND RESPONSIBILITIES OF DJV... 4 2.3 COMMITMENT BY APA GROUP... 5 2.4 DESCRIPTION OF DIRECTLINK TRANSMISSION SYSTEM... 5 2.4.1 Directlink Status within the National Electricity Market... 7 2.4.2 Overview of Cable Route... 7 2.4.3 Cables... 7 2.4.4 Converter Stations... 7 2.4.5 Operation of Interconnector... 7 2.4.6 Maintenance... 8 2.4.7 Engineering... 8 3. DESCRIPTION OF DIRECTLINK PLANNING PROCESS... 9 3.1 DEMAND MANAGEMENT METHODOLOGIES... 9 3.2 SYSTEM RELIABILITY PLANNING STANDARDS... 9 3.3 PLANNING STANDARDS MONITORING AND COMPLIANCE... 9 4. ASSET MANAGEMENT STRATEGIES... 10 4.1 RISK MANAGEMENT... 10 4.2 PUBLIC LIABILITY INSURANCE ARRANGEMENTS... 10 4.3 TECHNICAL SERVICE STANDARDS... 10 4.3.1 Supply Quality Standards... 10 4.3.2 Supply Reliability Standards... 10 5. SAFETY MANAGEMENT STRATEGIES... 12 5.1 STATEMENT OF SAFETY POLICY... 12 5.2 ANALYSIS OF HAZARDOUS EVENTS... 12 5.3 PROCEDURES FOR EMERGENCY EVENTS... 12 5.4 STRATEGIES FOR SAFE WORKING PROCEDURES... 12 5.4.1 Competency of Employees working in Directlink... 12 5.4.2 Permits and Access Arrangements... 13 5.5 TRAINING... 13 6. SCHEDULE OF REPORTS... 15 7. TECHNICAL STANDARDS, CODES AND GUIDELINES... 16 Page i
7.1 GENERAL... 16 7.2 CABLES... 16 7.2.1 Design... 16 7.2.1.1 Cable Insulation... 16 7.2.1.2 Cable Accessories... 17 7.2.2 Installation... 18 7.2.3 Operation... 18 7.2.4 Maintenance... 18 7.3 CONVERTER STATION... 18 7.3.1 Design... 19 7.3.2 Operation... 20 7.3.3 Maintenance... 20 7.4 EARTHING AND PROTECTION... 20 7.4.1 Design... 21 7.4.2 Installation of Earthing Systems... 21 7.4.3 Maintenance of Earthing Systems... 21 7.4.4 Maintenance of Protection Systems... 21 8. CUSTOMER INSTALLATION SAFETY PLAN... 22 8.1 OBJECTIVE OF THE PLAN... 22 9. PUBLIC ELECTRICAL SAFETY AWARENESS PLANS... 23 9.1 OBJECTIVE OF THE PLAN... 23 9.2 IDENTIFIED RISKS... 23 9.3 PUBLIC ELECTRICAL SAFETY AWARENESS... 23 9.4 DEPARTURES FROM CODES, STANDARDS OR GUIDELINES... 23 10. BUSH FIRE RISK MANAGEMENT PLANS... 24 10.1 OBJECTIVE OF THE PLAN... 24 10.2 BUSH FIRE RISK MANAGEMENT PLAN... 24 10.2.1 Identify Bush Fire Prone Areas... 24 10.2.2 Maintenance of Network Assets in Bush fire Prone Areas... 24 10.2.3 Vegetation Clearance... 24 10.2.4 Equipment and Network Asset Types / Construction Methods... 25 10.2.5 Complaints Recording System... 25 10.2.6 Liaison and Consultation with NSW Rural Fire Service, NSW Fire Brigades, Local Council... 25 10.2.7 Information Gathering and recording on fire hazards... 25 10.2.8 Procedures for handling very high fire danger... 25 10.2.9 Schedule of Reports... 25 Page ii
1. INTRODUCTION 1.1 GENERAL This document provides a description of the policies and practices, of the APA Group, that ensure the safety and technical management of the electricity infrastructure constructed, owned and operated by the APA Group within New South Wales.. 1.2 OBJECTIVE OF NETWORK MANAGEMENT PLAN As an owner and operator of Directlink electricity transmission assets, the APA Group is required to lodge the Network Management Plan with the NSW Department of Trade & Investment. The Network Management Plan has been prepared in accordance with Part 3 of the NSW Electricity Supply (Safety and Network Management) Regulation 2008. A copy of this approved plan may be found at http://www.apa.com.au. Further, this document will incorporate the followings plans in accordance with Clauses 10, 11 and 12 of the above regulation. Customer Installation Safety Plan Public Electrical Safety Awareness Plan Bush Fire Risk Management Plan In the above, the following areas are covered in this document. The safety of the public in relation to underground cables and enclosures of substations. The bushfire risk that may be posed by the network and the measures adopted to minimise that risk. The measures required to ensure safety at the connection points and compatibility with the network(s) to which Directlink is connected. The management system adopted to ensure the safety of the APA Group s staff, and contractors. 1.3 STRUCTURE OF THE PLAN The network management plan has been structured as follows; Section 1 Introduction: Includes the scope of the requirements for the plan and the structure of the document including relevant references applicable and included in the development of the plan. Section 2 Directlink Transmission System: Provides background information and the main features of the Directlink Assets. This section also presents APA overall organisation structure. Page 1
Section 3 Description of Directlink Planning Process: Explains the Directlink demand management methodologies, reliability planning strategies and performance indicators. Section 4 Asset Management Strategies: Provides the details of risk management strategies, public liability insurance arrangements and service standards. Section 5 Safety Management Strategies: Summarises the training and safety permit system arrangements for APA and contractor personnel used to undertake the work, principally in the vicinity of energised high voltage equipment. Section 6 Schedule of Reports: Section 7 Technical Standards, Codes and Guidelines: Provides a detailed summary of the asset management plan requirements, including industry standards, codes and regulations applicable to the design, installation, operation, maintenance of Directlink assets. Section 8 Customer Installation Safety Plan: Ensure the provision of safe electrical installations for connection to the transmission or distribution system to which it relates and the safe connection of such installations to that system. Section 9 Public Electrical Safety Awareness Plans: Explains the details of measures taken for the safety of public with regard to Directlink network operations. Section 10 Bush Fire Risk Management Plans: Provides the details of objectives and bush fire risk management plans of Directlink network assets. 1.4 REFERENCES The following reference documents have provided the basis for preparation of this plan: 1. Electricity Supply Act 1995 (NSW) 2. Negotiated Network Service Provider Connection Agreement with Country Energy dated 06 Nov 2006 3. AER Decision on Directlink Joint Ventures Application for Conversion and Revenue Cap 03 March 2006 4. ENA Doc 001-2008 National Electricity Network Safety Code 5. ENA NENS 04-2006 National guidelines for safe approach distances to electrical and mechanical apparatus 6. DL-O-001: Directlink Operating Procedure for Overview of the Operation of Directlink Rev 1 (Oct 2007) 7. DL-O-002: Directlink Operating Procedure for Using the Directlink Local/Remote Operator Workstation Rev 1 (Oct 2007) 8. DL-O-003: Directlink Operating Procedure for Directlink Operations Rev 5 (Oct 2007) 9. DL-O-004: Directlink Operating Procedure for Operator Quick Reference and Troubleshooting Rev 2 (Oct 2007) Page 2
10. DL-OP-06: High Voltage Switching and Procedures Manual Rev 3, Apr 2008 11. DL-SP-06: Directlink Safety Plan Rev 0, Jun 2008 12. Health, Safety, Environment and Emergency Response Management Plan (Revision 1, Oct 2007) for Murraylink and Directlink Transmission Systems Maintenance Services Transfield Services 13. Directlink Maintenance Agreement with Transfield Services Final Ver 1-07 June 2007 14. APA Group corporate policy for Health, Safety and Environment 15. APA Group Crisis Management Plan 16. APA Group Work Safety and Hazard Management Plan 17. APA Group Risk Management Policy In addition to the above, specific national, international and electricity industry technical standards and codes applicable to the design, construction, commissioning, operation, maintenance and decommissioning of the assets are listed in this plan and in the Regulations. Page 3
2. DIRECTLINK TRANSMISSION SYSTEM 2.1 OVERVIEW OF DIRECTLINK JOINT VENTURE The Directlink Joint Venture (DJV) is an Australian partnership which operates and maintains the Directlink network assets. The DJV partners are 100 percent owned by Energy Infrastructure Investments (EII) and are registered as code participants within the National Electricity Market (NEM). APA Group ( APA ) manages and maintains Directlink for EII and is a shareholder in EII. APA Group is a major owner and operator of energy infrastructure in Australia with over 8,000km of gas transmission pipelines throughout the country plus interests in gas processing, gas fired electricity generation and electricity transmission. 2.2 ORGANISATIONAL ROLE AND RESPONSIBILITIES OF DJV The organisational structure for the operation and maintenance of Directlink is shown in Figure 1 below. Figure 1: APA Group Organisation Structure for Directlink DJV Board General Manager Transmission Operations Manager Transmission Operations Qld Operations Manager Power Transmission O & M Engineer O & M Supervisor Technical Compliance Officer Converter Maintenance Personnel Cable Easement Maintenance Personnel Control Room Contractor Document Control and Records Officer Page 4
2.3 COMMITMENT BY APA GROUP The APA Group commitment for health, safety and environment management is to: Provide a safe and healthy workplace for all our people and contractors; Recognise the consequences of handling hazardous materials and commit to the management and control of the risks that may exist in our business and facilities; Protect the community and support community health and environment aspirations; Protect and maintain the natural environment and its sustained use for future generations; Comply with all their obligations and commitments. The APA Group has well established systems and procedures in the operation and maintenance of high voltage DC transmission systems, gas transmission pipe line networks and gas processing facilities in Australia. 2.4 DESCRIPTION OF DIRECTLINK TRANSMISSION SYSTEM Directlink is an 180MW capacity High Voltage Direct Current (HVDC) transmission line in New South Wales. Directlink is completely within New South Wales, but effectively transfers power from the Queensland power system to the New South Wales power system. The converter stations are located at Bungalora and Mullumbimby in New South Wales. Directlink has been designed by ABB with HVDC Light technology and is characterised by a conservative design philosophy and good industry practice and the inclusion of redundant elements to maximize the safety and reliability of the installation. The Directlink facility is a bipolar DC link, and consequently there are no steady state earths return currents, so that any impacts on adjacent infrastructure caused by earth return currents, such as galvanic action on gas and water pipelines and interference on telecommunication services are negligible. Page 5
Figure 2: Directlink System Map Page 6
2.4.1 Directlink Status within the National Electricity Market Directlink commenced full commercial operation on 15 December 2000 as a market interconnector. On 06 May 2004, the Directlink Joint Venture (DJV) submitted an application to convert Directlink to a regulated network and be eligible to receive a maximum allowed revenue (MAR), in accordance with clause 2.5.2(c) of the National Electricity Code ((now National Electricity Rules). The Australian Energy Regulator s (AER) draft decision (8 November 2005) considered that Directlink should be allowed to convert to a prescribed (regulated) service. The draft decision concluded that Directlink is able to meet the requirements for conversion to a prescribed service. Following the AER decision the Directlink facility commenced operation as a regulated (or prescribed) service on 21 March 2006. 2.4.2 Overview of Cable Route The Directlink cable route is approximately is approximately 59km in length. A number of different techniques were applied to install the cables including open-cut-and-fill, direct burial by cable plough, galvanized steel troughing (GST), directional drilling. A total of six DC transmission cables are installed along the route. Each pair of cables is dedicated to a pair of converters and cannot be reallocated to a different pair of converters. The presence of the cable is indicated by above-ground cable marker posts. Survey drawings providing as-installed route information, including GPS co-ordinates, are lodged with the Dial-Before-You-Dig service. 2.4.3 Cables The DC cables consist of a central core of conducting material (aluminium), surrounded by a thick, solid polymer (XLPE) insulating layer. A screen or shield surrounds the insulating layer and an extruded aluminium layer bonded to the hard outer plastic (HDPE) insulating jacket completes the cable. 2.4.4 Converter Stations The converter stations at each end of the DC cable have essentially the same design, but are connected to 110kV and 132 kv AC systems at Terranora and Mullumbimby respectively. Each converter station consists of three independent 65 MVA converters. The 110 kv and 132 kv AC connections include electrical protection schemes that coordinate fully with the Powerlink, Country Energy, and TransGrid system protection schemes and achieve the protection clearance times required by the National Electricity Rules (NER). Automatic remote trip control schemes have also been implemented in the design of Directlink, to maintain the reliability of the Powerlink, Country Energy and TransGrid transmission systems. 2.4.5 Operation of Interconnector Directlink has a nominal bi-directional rated capacity of 180MW (at the receiving end), transferring power between Queensland and NSW state transmission systems. Operational control is from a manned (24 hours a day, 7 days a week) remote control room, staffed by fully trained operators. Directlink receives dispatch targets from AEMO Page 7
on a five-minute basis, in a manner similar to scheduled generation plant. Directlink dispatch (both direction and magnitude) is optimally determined by the NEM Scheduling, Pricing and Dispatch (SPD) software. 2.4.6 Maintenance The maintenance work for the Directlink network assets is undertaken in accordance with the requirements of the Directlink maintenance plan. The maintenance plan has been developed and is periodically reviewed to ensure that the maintenance activities meet the objectives of the Directlink asset management strategy. The implementation of the Directlink maintenance plan provides assurance that the following objectives are achieved. The equipment reliability is maximised. The delivered power meets the required quality of power supply. All personnel, involved with the maintenance, act and plan for action, in a manner that will not put any property or any person at risk of damage or injury. The network assets are maintained in good, long term operating condition. The requirements of DJV procedures, good electricity industry practices and applicable laws are met. The maintenance outages are planned and coordinated to minimise the impact on stakeholders, including electricity consumers, AEMO and TNSPs. Sufficient resources are deployed to meet the requirements of the maintenance plan and the human resources are sufficiently skilled and trained for the required work. 2.4.7 Engineering Directlink maintains a comprehensive database of engineering documentation detailing the technical and design aspects of the asset equipment. Details of design change, equipment and system failures are recorded through the implementation of the engineering change process. The engineering change process provides assurance that failure statistics are analysed to identify corrective actions, Design considerations and calculations are recorded, andtechnical drawings are updated. Page 8
3. DESCRIPTION OF DIRECTLINK PLANNING PROCESS 3.1 DEMAND MANAGEMENT METHODOLOGIES Directlink transfers power between two Country Energy transmission substations and effectively provides an inter-regional transmission service interconnecting the NSW and Queensland electricity networks. Directlink does not contract its transmission capacity and no loads directly connect to Directlink. Directlink power transfer is controlled by AEMO and Directlink service standards are defined by the AER and Country Energy. Consequently the demand management methodologies are not applicable to the Directlink network. 3.2 SYSTEM RELIABILITY PLANNING STANDARDS The DJV operates and maintains the Directlink transmission system to meet the requirements set by Country Energy and the targets set in the AER Decision on the Directlink Joint Ventures Application for Conversion and Revenue Cap. The adequacy of the transmission system and its need for development is assessed against these requirements and targets. 3.3 PLANNING STANDARDS MONITORING AND COMPLIANCE Directlink continuously monitors its performance, against the requirements set by Country Energy and the targets set in the AER, through its 24 hours a day 7 days a week control centre. Directlink reports internally each month on its performance against the requirements set by Country Energy and the targets set in the AER. These reports are available to relevant APA staff and are generally not available publicly. Directlink reports annually to the AER on its performance against the targets set in the AER Decision on the Directlink Joint Ventures Application for Conversion and Revenue Cap. The results of its performance are publically available from the AER web site. The Directlink annual performance measures and targets are as follows. Performance Measure Target Scheduled circuit availability 99.45% Forced outage circuit availability in peak periods 99.23% Forced outage circuit availability in off peak periods 99.23% Page 9
4. ASSET MANAGEMENT STRATEGIES 4.1 RISK MANAGEMENT The effective management of risk is central to the continued safe and reliable operation of Directlink. The APA Group Risk Management Policy ensures that: Appropriate systems are in place to identify all material risks that the Company faces in conducting its business; The impact of identified risk is understood, and appropriate limits set to control exposures to those risks; Appropriate responsibilities are delegated to control the identified risk effectively; In order to minimise the risks involved with the Directlink network asset management, the DJV implements the APA Group Risk Management Framework including maintaining a risk register which indentifies the risks and appropriate risk management controls and actions. 4.2 PUBLIC LIABILITY INSURANCE ARRANGEMENTS Directlink is covered by the APA Group public liability insurance policy. The policy provides in excess of $100m insurance cover per event. As per the Directlink maintenance agreement with Transfield Services, the contractor is required to organise appropriate insurance to cover the liability against any damage or loss to any property, and for injury or death to any person, which may arise in the course of carrying out the Directlink Maintenance Services. 4.3 TECHNICAL SERVICE STANDARDS 4.3.1 Supply Quality Standards Directlink has been designed to meet the standards imposed by the National Electricity Rules. DJV undertakes to maintain these standards. Additionally, the DJV is party to a connection agreement with Country Energy which specifies power quality obligations which the DJV undertakes to meet. Directlink continuously monitors on its performance, against the supply quality standards, through its 24 hours a day 7 days a week control centre. 4.3.2 Supply Reliability Standards The supply reliability standards are the service standards set by Country Energy and the Australian Energy Regulator in their decision on the Directlink Joint Ventures Application for Conversion and Revenue Cap. The AER service standards are detailed in Appendix B of the decision. Refer the item 3 of Section 1.4. Page 10
Directlink reports internally each month on its performance against the requirements set by Country Energy and the targets set in the AER. Directlink reports annually to the AER on its performance against the targets set in the AER Decision on the Directlink Joint Ventures Application for Conversion and Revenue Cap. The results of its performance are publically available from the AER web site. Page 11
5. SAFETY MANAGEMENT STRATEGIES 5.1 STATEMENT OF SAFETY POLICY The APA Group s Health, Safety and Environment Policy demonstrates its commitment and priority towards the safety and environmental responsibility in all their operations. Directlink safety policies and procedures have been developed to control risks and ensure the safety of all personnel who are required to work on or in the vicinity of Directlink network assets in accordance with the: Electricity Supply Act 1995 (New South Wales) Electricity Supply (Safety and Network Management) Regulation 2002 ESAA NENS 01 2006: National Electricity Network Safety Code ESAA NENS 04 2006: National Guidelines for Safe Approach Distances to Electrical Apparatus It is essential that all authorised personnel/contractors are familiar with and strictly adhere to the Directlink safety policies and procedures to ensure safe working conditions and practices. When working with Directlink network assets, if any person has concern for the safety of personnel or plant, that person should immediately cease work, advise the relevant parties and/or implement appropriate mitigation measures. 5.2 ANALYSIS OF HAZARDOUS EVENTS The recording and analysis of all hazardous events in Directlink operation are handled in line with the requirements of DL-SP-06 Directlink Safety Plan, and the APA Group HSE Incident Notification Requirements. A detailed analysis of the hazards associated with Directlink is included as an attachment to the DL-SP-07 Directlink Safety Manual. 5.3 PROCEDURES FOR EMERGENCY EVENTS The APA Group Crisis and Emergency Management Policy specify the plans, processes, procedures and actions by which the APA Group will manage an emergency situation involving its electricity cables. 5.4 STRATEGIES FOR SAFE WORKING PROCEDURES 5.4.1 Competency of Employees working in Directlink The Directlink network has been designed and constructed in compliance to the National Electricity Safety Code (ESAA NENS 01-2001 and National Guidelines for Safe Approach Page 12
Distances to Electrical Apparatus (ESAA NENS 04-2003). In other words Directlink has been installed with all specified safety requirements given in the above guidelines. Transfield Services are the main contractor for all Directlink maintenance activities and therefore the contractor is responsible to ensure the competencies of the people working in Directlink maintenance works. In order to meet this requirement, Transfield Services have a system of developing people s competency in safe working practices and procedures, by way of training programmes, inductions, and workshops etc. This covers the people working with their sub-contractors as well. The following key areas are covered in these programmes. All people employed on the project are to attend a project specific Induction. All employees are provided with such information, instruction, training and supervision to enable them to perform their work in a manner that is safe and without risks to health, safety and/or environment. No employee or sub-contract employee is permitted to perform work unless that person holds the required qualifications/licences or competencies. 5.4.2 Permits and Access Arrangements The permit and access arrangements for Directlink network operation and maintenance have been defined in the DL-OP-06: High Voltage Switching and Procedures Manual. It covers the following key areas. Access to high voltage installations Procedure for submitting application for access permit High voltage switching Access to high voltage equipment Energising high voltage equipment All contractors working in Directlink are made aware of these access permit systems and arrangements for a safe working environment. The main contractor, Transfield Services, has well defined systems and procedures to make people aware of the above procedures and practises as explained in Section 5.4.1 above. 5.5 TRAINING DL-OP-06: High Voltage Switching and Procedures Manual (Section 2) define the training requirements for Directlink operation. In general all employees working in the Directlink network operation shall have the respective training course before or after joining Directlink or its contractors. Exemptions are given those who can demonstrate prior working knowledge or relevant current certifications with their respective area of working. Page 13
Contractors working in Directlink are responsible for training of their people and subcontractors. Depending on training and working knowledge / experience, certain authorisations levels are defined to perform and take the responsibility of different tasks. Refer to Section 2 of DL-OP-06). The following training courses relate to high voltage switching procedures; HV Switching Course (External) Directlink Switching Procedures (Internal) Electrical Safety Course (External) Any combination of the above three courses First Aid Course (external) Page 14
6. SCHEDULE OF REPORTS As per the Clause 6 (6) of the Electricity Supply (Safety and Network Management) Regulation 2002, Directlink submits the following reports to the Director-General of the Department of Water and Energy (NSW). Transmission Network Service Provider - Annual Report Individual reports on each serious electrical and network accident within one week of each accident. In addition to those above, DJV produces monthly internal management reports to monitor the operation of the Directlink network. Page 15
7. TECHNICAL STANDARDS, CODES AND GUIDELINES 7.1 GENERAL The design, installation, operation and maintenance of Directlink is based on making the facility safe for the electrical service conditions and the physical environment in which it operates. The design, installation, operation and maintenance of Directlink complies with the specific standards, codes and guidelines stated in the following sections and with the requirements set out in the Safety and Technical Requirements of the Regulations under the Electricity Act 1995 (NSW) and accompanying Schedules. 7.2 CABLES The power lines comply with the standards, codes and guidelines listed in National Electricity Safety Code (ESAA NENS 01-2001) where applicable, or appropriate alternative industry standards that achieve the same or better safety and technical outcome. The following specific standards and guidelines are also applicable: Cigré - Recommendations for mechanical testing - published in Electra 171 Cigré - Recommendations for tests of power transmission DC cables for a rated voltage up to 800kV - published in Electra 189 Cigré - Recommendations for testing of long AC submarine cables with extruded insulation for system voltage above 30(36)kV to 150(170)kV - published in Electra 189 IEC 60840 - Power cables with extruded insulation and their accessories - test methods and requirements IEC 60228 - Conductors of insulated cables IEC 60229 - Tests on cable over sheaths which have a special protective function and are applied by extrusion 7.2.1 Design 7.2.1.1 Cable Insulation Design Requirement The cable design provides a level of insulation that will operate safely for the 40 year design life of the line. Conditions applying Nominated system voltage levels: DC Voltage ± 80 kv (nominal) AC Voltage 132 kv RMS (3-phase) at NSW side AC Voltage 110 kv RMS (3-phase) at Queensland side AC voltage within Converter Building 165kV RMS 3-phase Page 16
Applicable Regulations, Standards and Codes industry standards for both the AC and DC cables, including those listed above. 7.2.1.2 Cable Accessories Design Requirement The design of the cable accessories matches the design performance of the cables. Conditions applying As for cables. Applicable Regulations, Standards and Codes industry standards, including those listed above. a. Cable Rating Design Requirement The cable design is such that at maximum current flow conditions the operating temperature of the insulating medium will not be compromised. Conditions applying Normal and emergency electricity service conditions. Installation arrangement direct in ground burial, with selected excavated material backfill and all laid galvanised steel troughing over its length Prevailing physical environment. Applicable Regulations, Standards and Codes Relevant sections of IEC 60287 Electric cables - Calculation of the current rating or equivalent. b. Cable Short Circuit Current Rating Design Requirement The cables are designed with a conductor and metallic screen size that will not cause the maximum short duration temperature of the insulating and non metallic screening mediums to be exceeded within the time taken for protection devices to clear abnormal system conditions Conditions applying The range of fault conditions that could reasonably be expected to prevail on the system. Applicable Regulations, Standards and Codes Industry Standards, including those listed above for the DC Cable. IEC 60949 Calculation of thermally permissible short-circuit currents, taking into account non-adiabatic heating effects or equivalent - for the AC Cable. c. Engineering Risk Analysis Directlink is a bipolar (not a monopole) DC transmission system. As such all of the DC current flows down one cable and back on the second cable. Since there are no steady state earth return currents, any impact on adjacent infrastructure such as gas and water pipelines and telecommunication services is minimized. Page 17
7.2.2 Installation Design Compliance Installation of the AC and DC cables is designed to be safe and compliant with the following regulated requirements: a. Mechanical Protection Mechanical protection covers, conduit, or trunking have been used. Covers used for direct in-ground buried cable sections are continuous strips of heavy duty PVC, 5mm thick, and installed 300mm above the cables. For all roads and rail crossings the cables are protected using HDPE or cast iron conduits inserted after directional boring. Voids are filled with bentonite or similar material to improve the heat transfer properties. b. Depth of Burial There is no regulated requirements for the HVDC system voltages. The 0.9m (clear cover) burial depth exceeds the cover required for AC cables energised at greater than 150kV and provides an increase in depth commensurate with agricultural and other land use requirements in the area. c. Register of Lines Survey drawings providing as-installed route information, including GPS co-ordinates are lodged with the Dial-Before-You-Dig service. Cable location information is available to the general public through Dial-Before-You-Dig on telephone number 1100 or on website www.dialbeforeyoudig.com.au. Dial- Before-You-Dig refers contact and site location details to the Directlink Cable Maintenance Contractor for provision of relevant plans and location assistance to inquirers. Depending on the inquiry, arrangements may be made for a site inspection by a cable maintenance service provider. 7.2.3 Operation The AC and DC cables are to be operated safely within the design and installation limitations determined for the system and the requirements of connection agreements, as monitored continuously by the Directlink Control Centre. 7.2.4 Maintenance The AC and DC cables are to be maintained as safe in accordance with the manufacturers and installers recommendations, including monitoring and condition testing of the cables. Operational procedures for the operation, isolation, earthing, testing, maintenance and repair of AC and DC cables are documented. 7.3 CONVERTER STATION The Converter station complies with the standards, codes and guidelines listed in National Electricity Safety Code (ESAA NENS 01-2001) where applicable, or appropriate alternative industry standards that achieve the same or better safety and technical outcome. The following specific IEC standards and guidelines are also applicable: IEC 60076, Power transformers IEC 60099, Surge arresters IEC 60146, Semiconductor converters IEC 60265, High-voltage switches Page 18
IEC 60296, Specification for unused mineral insulating oils for transformers and switchgear IEC 60420, High-voltage alternating current switch-fuse combinations IEC 60947, Low-voltage switchgear and control gear IEC 60971, Semiconductor converters. Identification code for converter connections IEC 61378-2, Converter transformers - Part 2: Transformers for HVDC applications IEC 61466, Composite string insulator units for overhead lines with a nominal voltage greater than 1000 V IEC 61000, Electromagnetic compatibility (EMC) IEC 62271, High-voltage switchgear and control gear 7.3.1 Design a. Building and Enclosures are designed to be secure, including appropriate arrangements to prevent entry by unauthorised persons, installation of danger warning and unauthorised entry prohibition signs on all entrances, plus prevention measures against intrusion of foreign objects that could interfere with the safe operation of the electrical equipment. b. Fencing around the converter station compound is designed in accordance with the requirements of ESAA NENS 04-2003. c. Plant, Equipment and Line Insulation Design requirement All electrical plant and equipment is designed with a level of insulation that will operate safely for the design life of the item. Conditions applying Nominated system voltage levels: DC Voltage ± 80 kv (nominal) AC Voltage 132 kv RMS (3-phase) at NSW side AC Voltage 110 kv RMS (3-phase) at Queensland side AC voltage within Converter Building 78.5 kv RMS (3 phase) d. Clearances The converter station outdoor switchyard is designed to provide safe operating and working clearances from live electrical equipment, including clearances to buildings and structures, in accordance with the requirements of ESAA NENS 04-2003. The inside of the converter building is considered a secured area with entry only by trained and authorised personnel under an access permit regime. The area is secured and castel keyed to prevent inadvertent access. Clearances inside of the converter building are adequate to ensure the safe operation of all electrical apparatus housed. Page 19
e. Thermal Rating Plant, equipment and connections will carry the electrical load currents for which they are designed without failure. Conditions applying Ambient climatic conditions, as follows: f. Fault Rating Elevation above sea-level < 1000m Ambient dry-bulb temperature range (design) -5 0 C to +45 0 C Maximum wet-bulb temperature +23 0 C Maximum daily 24-hour mean dry-bulb temp +30 0 C Plant, equipment and connections are designed to carry the short circuit currents required for the correct operation of the installed electrical protection devices. Suppliers of plant, equipment and materials are required to demonstrate that the items are suitable for operation under the specified normal and abnormal operating conditions and in the prevailing physical environment. 7.3.2 Operation The converter station is to be operated safely within the determined design and installation limitations, as monitored continuously by the Directlink Control Centre. The operation will at all times meet the requirements of the Connection Agreement between DJV and Country Energy, and any other conditions for operation as agreed between DJV and AEMO or as specified in the National Electricity Code. At present Directlink utilises Country Energy s control room (manned 24 hours a day, 7 days a week), staffed by trained personnel experienced in the operation, control and monitoring of electrical assets. 7.3.3 Maintenance The converter station is to be maintained to be safe in accordance with the manufacturers and installers recommendations for the inspection, condition monitoring, maintenance and testing of the equipment. A regular planned maintenance and inspection program is documented, based on the manufacturers recommendations and good industry practice. A maintenance management system schedules all planned maintenance and collects maintenance history data. Trained and experienced maintenance personnel carry out both planned and breakdown maintenance. The maintenance program includes the cables, converter station primary equipment, protection and control systems, earthing, civil infrastructure and auxiliary systems. 7.4 EARTHING AND PROTECTION Earthing and electrical protection systems are designed and installed and are required to be maintained to keep the electrical equipment in a safe condition. The earthing and protective devices will detect and isolate potentially unsafe electrical conditions in compliance with the standards, codes and guidelines listed in National Electricity Network Safety Code, or appropriate alternative industry standards that will achieve the same or a better safety and technical outcome. Page 20
7.4.1 Design a. Protective Equipment Design Requirement Reliable and high speed operation Conditions applying Abnormal system conditions likely to occur b. Earthing and Ancillaries Design Requirement Reliable passage of fault current Conditions applying Abnormal system conditions likely to occur c. Step and touch potentials and earth potential rise Design Requirement Must be effectively earthed and within maximum safe levels Applies to Uninsulated metal or reinforced concrete that forms part of an electricity installation, is accessible to people and may experience a rise in voltage in the event of an insulation failure within the electricity system. 7.4.2 Installation of Earthing Systems Earthing systems are installed in a manner that provides protection from mechanical damage, inadvertent interference and chemical deterioration. Termination and jointing of earthing components is by a method specifically developed as suitable for long-term durability of earthing systems. 7.4.3 Maintenance of Earthing Systems The resistance of the earthing systems to the general earth mass is periodically measured and the systems inspected, in accordance with the requirements of standards and guidelines listed in National Electricity Network Safety Code. Maintenance is carried out as necessary to maintain the effectiveness of the earthing systems. DJV has implemented an earthing system maintenance program based on the recommendations of the IEEE Guide for Safety in AC Substation Grounding (IEEE Std 80-2000). 7.4.4 Maintenance of Protection Systems The protection systems are periodically tested in accordance with the manufacturers recommendations to validate the detection sensitivity, speed of operation, discrimination of load currents and for correct coordination with the other protection systems. Page 21
8. CUSTOMER INSTALLATION SAFETY PLAN 8.1 OBJECTIVE OF THE PLAN The objective of a customer installation safety plan is to ensure the provision of safe electrical installations for connection to the transmission or distribution system to which it relates and the safe connection of such installations to that system. Directlink is a HVDC transmission line linking two high-voltage substations embedded in the NSW state power grid. The link has a fixed maximum capacity for transmitting power and directly connects to Country Energy transmission substations at both ends, with no other customer installations connected in between. Modifications to the connections are controlled by the connection agreements between the DJV and Country Energy and the DJV undertakes to comply with the requirements of the connection agreement. As such a Customer Installation Plan is not directly applicable for Directlink. Page 22
9. PUBLIC ELECTRICAL SAFETY AWARENESS PLANS 9.1 OBJECTIVE OF THE PLAN The objective of a public electrical safety awareness plan is to warn the public of the hazards associated with electricity in relation to a network operator's transmission or distribution system. 9.2 IDENTIFIED RISKS Directlink has identified the following potential risks to the public from its assets. Unauthorised access in substations Excavation in vicinity of the DC cables Vegetation clearing in vicinity of the DC cables 9.3 PUBLIC ELECTRICAL SAFETY AWARENESS Directlink focuses its public electrical safety awareness program in the follow areas. Maintaining clear signage indicating the presence of the high voltage cables. Maintaining accurate plans of the DC cable location with the Dial-Before-You-Dig service. Providing a free cable location service for the Directlink underground cables. Liaising with local and state government authorities and emergency services to maintain awareness of the location of the Directlink assets. Maintaining publically available management plans in accordance with the requirements of the Electricity Supply (Safety and Network Management) Regulation 2002 9.4 DEPARTURES FROM CODES, STANDARDS OR GUIDELINES Not applicable at this stage. Page 23
10. BUSH FIRE RISK MANAGEMENT PLANS 10.1 OBJECTIVE OF THE PLAN The objectives of a Bush Fire Risk Management Plan are as follows: to ensure public safety, to establish standards that must be observed when electricity lines operate near vegetation, to reduce interruptions to electricity supply that are related to vegetation, to minimise the possibility of fire ignition by electricity lines. 10.2 BUSH FIRE RISK MANAGEMENT PLAN 10.2.1 Identify Bush Fire Prone Areas Overhead transmission lines can touch in high winds and initiate a bushfire. The only overhead conductors incorporated in the Directlink asset are AC conductors within the converter station grounds. Consequently there a low risk of the overhead cables causing a bush fire. The Directlink DC cables present a very low risk of the cables causing a bushfire as they are either completely enclosed inside galvanised steel troughing or buried for their entire length. Therefore there are no bushfire prone areas as far as the electricity regulations are concerned. However, the DJV is continuously inspecting and monitoring the areas surrounding the Directlink assets to manage the risk from bushfires. 10.2.2 Maintenance of Network Assets in Bush fire Prone Areas Maintenance of Directlink network assets in bush fire prone areas are handled in line with the respective safety codes and standards. The DJV undertakes maintenance to control vegetation growth along the DC cable route, maintaining adequate fire breaks around the galvanised steel troughing section of the route. The DJV undertakes maintenance to prevent vegetation growth within the converter station grounds. The DJV also ensures adequate fire breaks are maintained around, the two converter stations. 10.2.3 Vegetation Clearance DJV is making arrangements to clear all vegetation in Directlink easements in line with the guidelines given in the Native Vegetation Act 2003 and other relevant Safety codes and standards. Page 24
10.2.4 Equipment and Network Asset Types / Construction Methods Directlink network assets / equipment are installed in line with the guidelines given in the National Safety codes and standards to avoid or minimise the potential fire risks. 10.2.5 Complaints Recording System APA maintains an inquiry line to receive complaints and refer these to the specific business areas when appropriate. 10.2.6 Liaison and Consultation with NSW Rural Fire Service, NSW Fire Brigades, Local Council APA / DJV are in contact and consultation with the NSW rural fire service, NSW fire brigade and respective local councils in Directlink network operation as well as gas pipeline operation. 10.2.7 Information Gathering and recording on fire hazards DJV is in the process of establishing a contract for periodical inspection of the Directlink network assets and the recording relevant information for analysis. This is part of a risk management programme to minimise or avoid fire hazards. 10.2.8 Procedures for handling very high fire danger DL-SP-07 Directlink Safety Manual details the work procedures for handling of very high fire danger situations in line with other national and international safety standards. 10.2.9 Schedule of Reports All events and incidents will be summarised and included in the reports sent to the Director General of the Department of Water and Energy (NSW) under the Directlink Network Management Plan. Page 25