11 kv Indoor Switchgear - SCADA Controlled

Transcription

1 Specification 11 kv Indoor Switchgear - SCADA Controlled Important Warning This document is one of a set of standards developed solely and specifically for use on the rail network owned or managed by the NSW Government and its agencies. It is not suitable for any other purpose. You must not use or adapt it or rely upon it in any way unless you are authorised in writing to do so by a relevant NSW Government agency. If this document forms part of a contract with, or is a condition of approval by, a NSW Government agency, use of the document is subject to the terms of the contract or approval. This document may not be current. Current standards are available for download from the Asset Standards Authority website at State of NSW through Transport for NSW

2 Standard governance Owner: Authoriser: Approver: Lead Electrical Engineer, Asset Standards Authority Chief Engineer Rail, Asset Standards Authority Director, Asset Standards Authority on behalf of ASA Configuration Control Board Document history Version Summary of change 1.0 First issue For queries regarding this document, please the ASA at or visit State of NSW through Transport for NSW

3 Preface The Asset Standards Authority (ASA) is an independent unit within Transport for NSW (TfNSW) and is the network design and standards authority for defined NSW transport assets. The ASA is responsible for developing engineering governance frameworks to support industry delivery in the assurance of design, safety, integrity, construction, and commissioning of transport assets for the whole asset life cycle. In order to achieve this, the ASA effectively discharges obligations as the authority for various technical, process, and planning matters across the asset life cycle. The ASA collaborates with industry using stakeholder engagement activities to assist in achieving its mission. These activities help align the ASA to broader government expectations of making it clearer, simpler, and more attractive to do business within the NSW transport industry, allowing the supply chain to deliver safe, efficient, and competent transport services. The ASA develops, maintains, controls, and publishes a suite of standards and other documentation for transport assets of TfNSW. Further, the ASA ensures that these standards are performance based to create opportunities for innovation and improve access to a broader competitive supply chain. This standard has been updated from RailCorp document EP SP 11kV AC Indoor SCADA Controlled Switchgear Fitted with Stationary (Non-Withdrawable) Switching Devices. This RailCorp document is withdrawn with the publication of this specification. This document is a first issue. State of NSW through Transport for NSW Page 3 of 59

4 Table of contents 1. Introduction Purpose Scope Application Reference documents Terms and definitions Functional requirements of 11 kv indoor switchgear Switchboard requirements Circuit breaker specific ratings Busbar inter-panel partition Busbar earthing facility Switchboard extension Earthing bar Transient earth clamp Current transformers for circuit breaker Current transformer rating plate Voltage transformers for switchboards Low voltage cabinet for secondary equipment Circuit breakers Circuit breaker interrupters Circuit breaker operating mechanisms Circuit breaker indications Switchgear auxiliary equipment Interlocks Mechanical interlocks Circuit breaker and switch panel HV cable compartment Fully insulated cable terminations Non-fully insulated cable terminations Cable compartment size Surge arresters for 11 kv switchboards Circuit earthing facilities Voltage detecting system Circuit test facilities Padlocking Floor fixing and penetration details Segregation of LV wiring in HV compartment Instruments, transducers and metering Current transducers Voltage transducers Ammeters Voltmeters Watthour meter State of NSW through Transport for NSW Page 4 of 59

5 23. Busbar and circuit protection High impedance bus zone protection Internal arc fault detection scheme Feeder protection System transformer protection Distribution transformer protection SCADA indications and controls Binary indication and ACCB control Analogue indication Controls Appendix A - Switchboard configurations...29 A.1 Switchboard configurations...29 A.1.1 Switchboard panel configuration codes A.1.2 Bus coupling circuit breaker A.1.3 Capacitor/harmonic filter circuit breaker A.1.4 Feeder circuit breaker (non Auto) A.1.5 Feeder network switch (supervisory indication only) Appendix B - Typical switchboard configurations...34 B.1 Supply point switchboard configurations...34 B.2 Switching station switchboard configurations...34 B.3 System substation switchboard configurations...34 B.4 Mid point switching switchboard configuration...35 B.5 Bus coupled circuit breaker switchboard...35 B.6 Example switchboard configurations...35 Appendix C - Integrated system support requirements...46 C.1 Integrated support objectives...46 C.2 Equipment supplier deliverable...46 Appendix D - Tests...47 D.1 Routine tests...47 D.2 Type tests...47 Appendix E - Data set associated with the equipment...48 E.1 Information...48 E.2 Technical schedule...48 E.3 Life cycle costing...48 Appendix F - Technical schedule...49 Appendix G - Guide to information requirements for Request for Tender...58 State of NSW through Transport for NSW Page 5 of 59

6 1. Introduction This document details the requirements for indoor 11 kv non-withdrawable SCADA controlled switchgear for use in the RailCorp distribution system. All information required to ensure that the switchgear is electrically suitable for the RailCorp network is contained in this document or referenced by this document. 2. Purpose 2.1. Scope The purpose of this document is to specify the requirements for 11 kv non-withdrawable SCADA controlled switchgear to enable suitable equipment to be procured for use in the RailCorp network. This document provides the specifications of factory assembled, type tested, metal enclosed, single busbar, fixed (stationary) switching devices designed for indoor installation on railway distribution systems operating at nominal 11 kv ac, three-phase, 50 Hz. The switchgear panels include equipment that comprises of a fixed functional unit with an associated off-load disconnector and interlocked earthing facility, in combination with the associated SCADA control, measuring, indicating, alarm and protective equipment, including interconnections, accessories, enclosures and supporting structure Application The requirements of this document apply to purchase or installation of a new 11 kv indoor switchboard in a RailCorp substation. These requirements are applicable from the date of issue of this specification. The requirements of this document are not applicable to existing 11 kv indoor switchboards currently in service in the RailCorp network. 3. Reference documents International standards IEC Voltage detection systems Australian standards AS :1985 International electrotechnical vocabulary - Switchgear, controlgear and fuses AS :1996 High-voltage test techniques - General definitions and test requirements State of NSW through Transport for NSW Page 6 of 59

7 AS 2067:2008 Substations and high voltage installations exceeding 1 kv ac AS 2629:2008 Separable insulated connectors for power distribution systems above 1 kv AS 2700:2011 Colour standards for general purposes AS 3760:2010 In-service safety inspection and testing of electrical equipment AS :2007 Instrument transformers - Current transformers AS :2007 Instrument transformers Inductive voltage transformers AS 60137:2008 Insulated bushings for alternating voltages above 1000 V AS :2001 High-voltage switches - Switches for rated voltages above 1 kv and less than 52 kv AS 60270:2001 High-voltage test techniques Partial discharge measurements AS 60417(all parts) Graphical symbols for use on equipment (identical to IEC 60417) AS 60529:2004 Degrees of protection provided by enclosures (IP Code) AS :2012 High-Voltage switchgear and controlgear - Common specifications AS :2008 High-voltage switchgear and controlgear - High voltage alternating-current circuit breakers AS :2005 High-voltage switchgear and controlgear - Alternating current disconnectors (isolators) and earthing switches AS :2005 High-voltage switchgear and control gear A.C. metal enclosed switchgear and controlgear for rated voltages above 1 kv and up to and including 52 kv AS :2005 High voltage switchgear and control gear - Dimensional standardardization of terminals Transport for NSW standards Several significant sets of requirements applicable to 11 kv ac indoor, supervisory controlled switchgear are common to other classes of equipment and are set out in the following TfNSW standards. The equipment shall comply with the relevant requirements set out therein. T HR EL PR Electrical Power Equipment - Integrated Support Requirements T HR EL SP Common Requirements for Electric Power Equipment EP SP Electrical Power Equipment - Design Ranges of Ambient Conditions EP SP Protection System Requirements for the High Voltage Network State of NSW through Transport for NSW Page 7 of 59

8 EP SP Insulation Coordination and Surge Arrester Selection EP SP Standard Voltage Tolerances 4. Terms and definitions The following terms and definitions apply in this document: ACCB alternating current circuit breaker ASA Asset Standards Authority CT current transformer MTM protection relay for the multi-tripping of ACCBs This is a manually reset relay with a hand reset flag. NER neutral earthing resistor RTU remote terminal unit SCADA supervisory controlled and data acquisition system TfNSW Transport for New South Wales UGOH underground to overhead (aerial line) VDS voltage detection system VPIS voltage presence indicating system VT voltage transformer For the purpose of this specification, the terms and definitions in AS and the following apply: circuit breaker a mechanical switching device that is capable of making, carrying and breaking currents under normal circuit conditions, and also of making, carrying for a specified time and breaking currents under specified abnormal conditions, such as those of a short-circuit circuit breaker panel a switchgear panel complete with a fixed circuit breaker, switch-disconnector, earthing switch and protection and control equipment earthing switch as defined in AS 1852(441) fixed circuit breaker a circuit breaker which is not a withdrawable part of the panel assembly in which it is mounted metal enclosed switchgear and controlgear switchgear and controlgear assemblies with an external metal enclosure intended to be earthed and completely assembled, except for external connections State of NSW through Transport for NSW Page 8 of 59

9 non-withdrawable switchgear switchgear such as circuit breaker and switches, which are not a withdrawable part of the panel assembly in which they are mounted rated insulation level the combinations of the rated lightning impulse withstand voltage and the rated short duration power frequency withstand voltage specified in AS 2650 rated normal current for main circuits and switching devices, the rms value of the current that they are designed to carry continuously under the specified conditions of use and behaviour rated peak withstand current for main and earthing circuits, the peak current associated with the first major loop of the short-time withstand current that a mechanical switching device is designed to carry in the closed position under prescribed conditions of use and behaviour rated short-time withstand current for main and earthing circuits, the rms value of current that the switching device is designed to carry in the closed position during a specified short time under prescribed conditions of use and behaviour rated voltage the highest rms phase-to-phase voltage of the supply on which the switchgear is designed to operate switch a mechanical switching device that is capable of making, carrying and breaking currents under normal circuit conditions, which can include specified operating overload conditions, and also capable of carrying for a specified time, currents under specified abnormal circuit conditions such as those of a short-circuit switchboard two or more switchgear panels coupled together in various combinations switch-disconnector as defined in AS 1852(441) switchgear a general term that covers switching devices and their combination with associated control, measuring, indicating, alarm, protective and regulating equipment, also assemblies of such devices and equipment with associated interconnections, accessories, enclosures and supporting structures, intended, in principle, for use in connection with the generation, transmission, distribution and conversion of electric energy 5. Functional requirements of 11 kv indoor switchgear The 11 kv indoor switchgear shall consist of 11 kv busbar, fixed type circuit breakers, disconnectors and associated control and protection equipment. The 11 kv indoor switchgear shall provide for the following: connection of 11 kv feeders, bus tie cables, system transformer and distribution transformer circuits to the 11 kv busbar isolation and earthing of feeders, bus tie cables, system transformer and distribution transformer circuits State of NSW through Transport for NSW Page 9 of 59

10 protection and SCADA control for 11 kv feeders, system transformer and distribution transformer circuits and sections on the 11 kv busbar connection, protection and SCADA control of 11 kv harmonic filter or capacitor banks means to perform a dc test on the HV cables, without disturbing existing HV cable connections 6. Switchboard requirements Table 1 provides details of general requirements of a switchboard for 11 kv indoor switchgear. Table 1 - Switchboard general requirements Parameter Switchboard type Class Method of neutral earthing of the system Main device type Busbar insulation medium IP rating Possible extension to switchboard Designation Metal enclosed Indoor Effectively earthed and non-effectively earthed Non-withdrawable (stationary) Cast resin or air IP3X Both sides The switchboard shall be designed and manufactured in accordance with the standards stated in Table 2 and Table 3 along with the specific class and classification. Equipment Switchgear (common specifications) Metal enclosed switchgear Table 2 - Switchboard standards Standard AS AS Current transformer AS Voltage transformer AS Degrees of protection provided by enclosure (IP code) AS General AS 2067 Switchgear status indicators (definite indication of position) AS Appendix A State of NSW through Transport for NSW Page 10 of 59

11 Table 3 - Switchboard standards with class Designation Standard Class Service conditions AS Normal (except for temperature which shall comply with EP SP) Refer to note 1. Partition class AS PI Internal arc classification (IAC) AS AFLR Earthing switch AS E2 Disconnector AS M2 Switch AS M1, E3 Circuit breaker (except capacitor) Capacitor switching AS AS M2, E2, C1 M2, E2, C1 Note 1: Where the switchgear does not meet the temperature requirements of EP SP, then the applicable derating factors shall be provided. Table 4 details switchboard and specific equipment rating requirements. Parameter Table 4 Switchboard common ratings Number of phases 3 Rating Rated system voltage (Ur) Rated frequency (fr) Busbar Rated normal current Rated lightning impulse withstand voltage (Up) Common value Across the isolating distance Rated short-duration power-frequency withstand voltage (Ud) Common value Across the isolating distance Rated short time withstand current (Ik) (for main and earthing circuits) Rated peak withstand current (Ip) (for main and earthing circuits) Rated duration of short circuit (tk) (for main and earthing circuits) Internal arc classification (IAC) Arc test current Arc test current duration 12 kv (minimum) 50 Hz Single 630 A or 1250 A Refer note kv (peak) Refer note kv (peak) 28 kv (rms) 32 kv (rms) 16 ka (rms) 40 ka (peak) 1 sec AFLR 16 ka 1 sec State of NSW through Transport for NSW Page 11 of 59

12 Parameter Rated supply voltage of closing and opening devices and of auxiliary and control circuits (Ua) Refer to note 3. Partial discharge level of complete switchboard including all components Rating Option V dc Option 2 50 V dc < 50 pc Note 1: The required busbar rating for a particular location is specified on the approved proposed operating diagram provided at the time of order. Note 2: The rated lightning impulse withstand voltages mentioned are specific to Australian conditions and compatibility with the existing RailCorp network. These values are not from the current version of AS Note 3: Auxiliary voltage will be nominated at time of order of switchboard. These requirements are specified in T HR EL ST, Common Requirements for Electric Power Equipment Circuit breaker specific ratings Table 5 and Table 6 provide details of specific ratings for the circuit breakers. Table 5 ACCB Common Ratings -1 Parameter (common to all ACCBs) Rating Rated supply voltage of closing and opening devices and of auxiliary and control circuits (Ua) Refer to note 1. Rated normal current (Ir)2 - Bus Tie Refer to note 2. Feeder System transformer Distribution transformer Capacitor/harmonic filter Rated short circuit breaking current (Isc) Rated duration of short circuit (tk) Interrupter type Number of trip coils Number of close coils 1 Breaking time Command response time both ON and OFF Option V dc Option 2 50 V dc Option A Option A 400 A 630 A 200 A 400 A 16 ka 1 sec Vacuum 2 independently operated coils < 60 msec (max) < 25 msec (max) State of NSW through Transport for NSW Page 12 of 59

13 Parameter (common to all ACCBs) Rated operating sequence Cables connected Rating O - 0.3s-CO-3min-CO Bottom front or rear and optional top Table 6 - ACCB Common Ratings -2 Parameter (applicable to capacitor ACCB) Rated short-duration withstand voltage (across the isolating distance) (Ud) Rating 12 kv ac rms with 13.5 kv dc offset Note 1: Auxiliary voltage will be nominated at time of order of switchboard. These requirements are specified in T HR EL ST Common Requirements for Electric Power Equipment. Note 2: The current ratings for the switchboard are mentioned in the proposed electrical operating diagram, provided at the time of order. The requirements specified in this document ensure that the switchboards will fully integrate into the RailCorp network in terms of operability, maintainability and technical compatibility Busbar inter-panel partition The switchboard shall be designed to have a partition between panels in the busbar compartment. This is required to contain an electrical fault associated with the busbar to the panel where the fault originated Busbar earthing facility If any part of the busbar requires routine maintenance then busbar earthing facilities shall be provided Switchboard extension The switchboard and associated functional units shall be designed so that an extension to an existing switchboard is possible at both ends with minimal dismantling to the existing switchboard. State of NSW through Transport for NSW Page 13 of 59

14 7. Earthing bar Each switchgear panel shall include two copper earthing bars, rated for maximum fault levels and not less than 120 mm² cross section area to facilitate earthing. To assist with stray current mitigation measures from the dc traction system, it may be necessary to connect 11 kv cable screens to a separate cable screen earth bar on feeder panels only. This arrangement is to facilitate future installation of a transient earth clamp. The cable screen earth bar shall be connected to the switchboard earth bar via removable links and shall be isolated from similar bars in adjacent panels. The cable screen earth bar shall be insulated from the frame of the switchboard by insulated mounts that have been rated for maximum earth potential rise and tested for at least 11/ 3 kv for 1 minute. The cable screen earth bar shall provide for connection of the removable link, three HV cable screens and two cable connections holes for a transient earth clamp. The switchboard earth bar shall interconnect adjacent switchgear panels and provide the following: switchgear bonding two cable connections to the main substation earth grid a removable link per feeder panel for connection to the insulated earth screen earthing bar three cable screens for panels other than feeders requirements for circuit test facility Earth termination requirements are provided in T HR EL ST Transient earth clamp The transient clamp acts as a dc decoupler to provide dc isolation between earthing points that are still ac connected. Under an ac earth fault the clamp impedance momentarily changes state to a virtual short circuit, acting to provide a direct connection of HV cable screens to the switchboard earth bar. The transient earth clamp blocks the path to dc stray current that may otherwise flow via the cable screen. Transient earth clamps (if required) are installed on feeder panels only. State of NSW through Transport for NSW Page 14 of 59

15 8. Current transformers for circuit breaker The circuit breaker panels shall be provided with protection and metering current transformers in compliance with EP SP Protection System Requirements for the High Voltage Network. The typical quantity of CTs required is as follows: feeder panel: 4 (BZ, PW, OC, metering) transformer panel: 4 (BZ, Tx diff, OC, metering) bus-tie panel: 2 (BZ, bus-tie cable protection) Where an alternative busbar scheme (such as arc detection) is installed then a CT for BZ will not be required. Refer to Appendix B for further detail on typical CT ratio and class. Specific CT requirements for individual switchboards will be provided in the protection concept report for individual switchboards which is issued at the time of order Current transformer rating plate A rating plate shall be fitted to each current transformer. A second identical plate shall be fixed within the LV compartment in a position that facilitates ease of access to read the information. 9. Voltage transformers for switchboards A three-phase voltage transformer or three single phase voltage transformers in compliance with EP SP shall be provided for each switchboard. A voltage transformer (VT) is required for each busbar and incoming supply transformer ACCB. Specific VT requirements for individual switchboards will be provided in the approved protection concept report which is issued at the time of order. For the maintenance and commissioning of protection relays, voltage conditions that would occur during earth faults shall be simulated and the supplier shall explain how this is achieved. The VT alarm, protection relay VT supply alarm and phase failure relay shall be in accordance with EP SP. State of NSW through Transport for NSW Page 15 of 59

16 10. Low voltage cabinet for secondary equipment The secondary equipment including protective relays, controls, transducers, metering and other systems shall be housed in a low voltage cabinet located on the relevant circuit breaker panel. The location of the panel shall be suitable to enable the installation of all secondary wiring and accessibility for terminating wiring, programming of protection relays and general testing and commissioning activities. The low voltage panel shall be a lockable, closed, fully shrouded and arc resistant cabinet of IP3X standard suitable for accommodating digital protection relays, test blocks, panel meters and other secondary equipment for control and measurement. Where it is appropriate, equipment may be mounted on a torsion resistant panel door. The cabinet shall be fitted with a removable gland plate, cable ducting and terminals. The layout within the cabinet shall ensure for the following: adequate room is provided for the termination of multi-core control cables, dc auxiliary supply cables and other miscellaneous cables that are required for interfacing with equipment within the substation cable terminals shall be readily accessible to enable connection of test equipment associated with protection relay testing and commissioning cable ducting within the cabinet shall be located to allow for the installation of multi-core control cables In particular, adequate room between duct and cable entry points to allow for the bending radius of cables internal cabinet colour shall be white Refer to T HR EL ST for details on low voltage wiring, terminals and labelling requirements. Mechanical drive elements shall not be installed in the low voltage cabinet. 11. Circuit breakers Circuit breaker panels shall comprise of a fixed circuit breaker, switch-disconnector and earthing switch and shall have specific ratings as specified in Table 5 and Table Circuit breaker interrupters Interrupters shall be capable of at least 10,000 operations at rated current and at least 50 operations at rated short circuit breaking current. State of NSW through Transport for NSW Page 16 of 59

17 The contacts of the interrupter shall be held open by a positive fail-safe device independent of interrupter vacuum. The closing arrangement shall be designed to give a positive closing action while overcoming the contact hold open device Circuit breaker operating mechanisms The circuit breaker operating mechanism shall be an integral part of the circuit breaker. The circuit breaker busbar isolator and associated earth switch shall be actuated mechanically. Auxiliary switches shall provide indication of each switch position. Any part of the circuit breaker mechanism that requires routine inspection and maintenance shall not be enclosed in any gas tight compartment. All circuit breaker operating mechanisms shall be the stored energy type by means of energy stored in a motor-charged spring with manual and electrical release. Solenoid based mechanisms shall not be used. Magnetic actuator type operating mechanisms will be considered, provided that full technical details of the proposed arrangement are supplied. Typical details shall include principle of operation, auxiliary power supply requirements, details on manual operation and how the requirement for duplicate trip coils is addressed. The suitability of existing dc battery and associated dc circuit wiring shall require assessment in existing locations Circuit breaker closing mechanism The circuit breaker closing mechanism shall be electrically operated, trip-free. The circuit breaker mechanism shall provide lockout that prevents closing, as specified in Section of AS 1852 (441): All circuit breakers in the closed position shall be able to trip-close-trip before the spring needs to be charged again Circuit breaker operation and control The circuit breakers shall be arranged for operation by local control and by remote supervisory control. Refer to Section 24.3 for further details. The circuit breaker shall close without delay when the close command signal is applied. While this command signal is applied, the circuit breaker shall not make a second attempt to close if it fails to close on the first attempt. The circuit breaker shall open without delay when the open command signal is applied independently to any of the trip coils or to all trip coils simultaneously. A mechanical push-button or similar device for tripping the circuit breaker shall be provided. State of NSW through Transport for NSW Page 17 of 59

18 Continuously rated control equipment shall be provided to make the successful closing of the circuit breaker independent of the length of time that the control switch is held in the CLOSE position. This shall ensure that only one closing attempt can be made if the control switch is held in the CLOSE position Circuit breaker auxiliary contacts A minimum of two normally open and two normally closed auxiliary switches rated at 5 amperes in a 125 V dc inductive circuit or a 415 V ac circuit shall be provided. These auxiliary switches shall be provided in addition to those essential to the circuit breaker operation Circuit breaker indications The circuit breaker and switch panel shall have indications clearly visible from the front of the panel (that is, either on the circuit breaker or on the circuit breaker panel). The circuit breaker / switchgear panel shall have the following definite indications: circuit breaker open/close This shall be implemented by a mechanically operated indicator, indelibly marked, to show whether the circuit breaker is open or closed. The word OPEN shall be visible only if the circuit breaker is open and the word CLOSED shall be visible only if the circuit breaker is closed. If colours are used in addition, then the colour green shall indicate the open condition and the colour red shall indicate the closed condition. switch disconnector open/close (if applicable) This shall be implemented by a mechanically operated indicator. earth switch position This shall be implemented by a mechanically operated indicator. stored energy device charged/discharged non-resettable operation counter (nominally mechanical) However, alternatives shall be accepted after if approved by ASA. 12. Switchgear auxiliary equipment Each switchgear panel shall be fitted with a control panel with the following: a local CLOSE and OPEN switch or push-buttons coloured red and green respectively LOCAL REMOTE (SUPERVISORY) changeover switch electrically operated indicating lights of the LED type State of NSW through Transport for NSW Page 18 of 59

19 a set of terminals for the termination of auxiliary wiring All auxiliary wiring for remote closing and tripping circuits, incoming dc control supplies and all spare auxiliary switches shall be connected to these terminals This control panel shall have the capability for installing instruments to measure voltage, current and energy. The requirement for which instruments are to be installed will be specified at the time of order. The requirements of any instrumentation to be fitted are set out in Section 22. Each switchboard shall be fitted with a voltmeter and associated phase selection switch to indicate the bus voltage. Anti-condensation heaters where required shall be provided. 13. Interlocks Interlocking requirements regarding operating lever actuation shall be designed to interrogation interlock principles. Operating levers can only be inserted or actuating forces may only act on the components if this is permitted by the appropriate operating condition of the associated functional unit. Digital switchgear interlock units are not accepted. Actuating levers shall remove or insert in clearly defined positions 'Close' or 'Open'. The interlocking shall comply with the following conditions: interlock between busbar isolator and outgoing earthing switch interlock between busbar isolator and circuit breaker interlock between the switch disconnector and the outgoing earthing switch interlock between the cable compartment cover and the outgoing earthing switch For cable testing, specific equipment shall be provided to eliminate the outgoing earth. Interlocks shall ensure that the disconnector cannot be moved or operated unless the circuit breaker is open. Interlocks shall ensure that the circuit breaker cannot be closed unless the disconnector is fully in the 'closed', 'isolated' or 'earth' position. State of NSW through Transport for NSW Page 19 of 59

20 13.1. Mechanical interlocks Facilities provided for operational access to parts of the switchgear panel that contain live components shall be mechanically interlocked. Access to such parts is not possible unless all live parts have been rendered safe, either by a visibly applied earth connection or by positively disconnected and screened from the remaining live parts. Mechanical interlocks shall be provided to ensure positive and substantial protection against malfunction. Mechanical interlocks shall be designed and constructed to ensure dependable fail-safe operation. Positive mechanical interlocking shall be provided to prevent inadvertent switching from the ON position to the EARTH position without a definite stop in the OFF position, or from the EARTH position to the ON position without a definite stop in the OFF position. Access to the test terminals shall only be possible when the associated earth switch is in the EARTH position. When the circuit test facility is in use, the disconnection shall not be able to close. The operator shall directly observe the making of the contacts in the circuit EARTH position. If the earthing of a circuit is not visible, the corresponding indication shall be directly coupled to the earthing mechanism to ensure fail-safe indication. If the switchgear panel is designed in a way that the circuit to be earthed is earthed through the main contacts of the circuit breaker, then the circuit breaker shall be interlocked. This is done so that it cannot be tripped by the protection relays or SCADA control while the circuit is earthed. An analysis shall be provided detailing the integrity of the interlocking system. The analysis shall include all possible failure modes and the controls employed to prevent an unsafe operation. A table shall be provided of all possible and inhibited states the switchgear may occupy. 14. Circuit breaker and switch panel HV cable compartment Each circuit breaker and switch panel shall be equipped with an 11 kv cable compartment interlocked with the ACCB for connection of the 11 kv cables. Due to the variety in physical configurations of existing substations in the RailCorp network there is the requirement for two separate options for access to the high voltage cable terminations. State of NSW through Transport for NSW Page 20 of 59

21 The two options are as follows: access to the high voltage cables from the front access to the high voltage cables from the rear The cable bushings shall be arranged side by side facing the front of the switchboard. Bushings shall be positioned to suit connection of three core cables with tails of equal length to facilitate phase transposition without re-terminating the cable. All cable compartments shall be adequately sealed to prevent entry of vermin and dust in compliance with IP3X. Each circuit breaker and switch panel shall provide the means to perform a dc cable test on the HV cables, without disturbing existing HV cable connections Fully insulated cable terminations All cable termination compartments shall be suitable for dead-break, separable, fully insulated and shielded system for connection of HV cables. The separable, insulated, shielded connection system shall comply with AS 2629 (or equivalent IEC, EN) and relevant ratings specified in Section Non-fully insulated cable terminations All cable termination compartments shall be suitable for air insulated termination. compartment shall have at a minimum the clearances specified in AS The To provide protection against flashover due to rodents or high humidity, removable and re-installable elastomeric insulating boots (or approved alternative) shall be fitted Cable compartment size The cable compartment shall accept single, three-conductor belted or three core dry type cables including separately lead sheathed paper or XLPE insulated cables of up to 240 mm² in size. Where three phase cables are to be terminated the dimension of the cable compartment shall enable adequate clearances for crossing of cable cores. All cable compartments shall be of dimensions such that full standard cable withstand power frequency tests as specified in AS can be conducted after cable termination is complete. The minimum of one cable shall be achieved without sacrificing space for surge arrester equipment if required. State of NSW through Transport for NSW Page 21 of 59

22 Where the cable compartment design results in a length of unsupported cable greater than the length recommended by cable manufacturers, then a method of cable support is required within the compartment. The standard cable compartment requirement is for bottom entry of cables. A limited requirement for top entry of cables applies. Details of the cable connections options shall be nominated in the technical schedule provided in Appendix F. 15. Surge arresters for 11 kv switchboards Surge arresters are not normally required in 11 kv switchboards installed on the RailCorp network. This is valid for the standard connection arrangement where the feeder consists of cable to a pole and the 11 kv surge arrester is located on that pole as part of the standard UGOH (underground to overhead - aerial) arrangement. 16. Circuit earthing facilities All panels shall be equipped with circuit earthing switches manufactured and tested in accordance with the relevant standard specified in Section 6. Earth switches shall be the integral type. The earthing of the circuit cables shall be effected via a separately designed make-proof earthing switch. The earthing shall be located directly on the circuit cable and designed without interposing further switching devices. The earthing system shall be designed and tested for making a live circuit with a prospective peak fault current in accordance with the switchboard requirements specified in Table 1 in Section 6. Each circuit-earthing switch shall be mechanically interlocked with the corresponding circuit breaker or switch. Refer to Section 13 for interlocking requirements. The earthing switch shall be fully rated for fault making to the requirements specified in Section 6. Each switch shall be provided with a fail safe indicating device to positively indicate whether it is in the OPEN OR EARTH position and the words 'OPEN' and 'EARTH' shall be used for the respective indication of these positions. The equipment shall be configured to allow the position of the earth switch contacts in the EARTH position to observe directly. Appropriate long life, maintenance free illumination shall be provided. The light source shall be replaced without the need for isolating HV equipment or significant disassembly of the switchgear. State of NSW through Transport for NSW Page 22 of 59

23 17. Voltage detecting system A voltage detection system (VDS) in accordance with IEC with integrated display to detect the following shall be provided for all HV circuits: dead state operating voltage phase balance A voltage presence indicating system (VPIS) in accordance with IEC is acceptable if a VDS system is not available. Suitable capacitive voltage dividers fitted in the cable connection area is acceptable. Appropriate connections shall be provided to enable phase comparison in normal operating conditions. An optional feature is for remote indication of 11 kv cable voltage status and interlocking with the earth switch. Interlocking shall inhibit the earthing of live circuit conductors. 18. Circuit test facilities Each circuit breaker panel shall incorporate an integral type circuit test facility. All test facilities shall be suitable for the application of dc test voltages associated with the after-installation testing of power cables. They shall be rated for the same system voltage as the switchgear. The test facility shall facilitate the connection of test equipment with the circuit earthed and then allow the earths to be removed with the test equipment still connected. A hand applied earthing set shall be connected to the circuit side of each circuit breaker panel for use in conjunction with test equipment. The earth connection shall be applied or removed independent of the application or removal of the test equipment connection. External removable accessories shall be used to achieve this function. 19. Padlocking Facilities shall be provided to padlock the following: disconnector in the closed, open and earth positions circuit breaker in the open positions and the closed position while the disconnector is in the earthed position circuit test facility, if applicable (see Section 12) State of NSW through Transport for NSW Page 23 of 59

24 All padlocking facilities shall be suitable for padlocks with a 6 mm shank diameter. 20. Floor fixing and penetration details All equipment required for the fixing of the switchgear to the floor shall be provided, inclusive of the switchboard. Drawings detailing the required floor levels, penetrations and any other civil requirements for the installation of the switchboard shall be provided. 21. Segregation of LV wiring in HV compartment Any low voltage wiring within HV compartments shall be segregated, mechanically protected and installed to provide adequate protection from a HV fault damaging the LV circuits. Compliance with this requirement is detailed in the technical schedule provided in Appendix F. 22. Instruments, transducers and metering All instruments, transducers and metering equipment that are required to be fitted shall comply with this section and the relevant requirements in T HR EL ST. All indicating instruments shall be flush-mounted industrial type instruments that comply with the requirements of the following IEC standards: IEC , IEC , IEC , IEC , IEC and IEC The instruments shall be clearly visible and easily readable from a standing position in front of the panel. Analogue instruments shall have a scale length of at least 90 mm. All instruments on a switchboard shall be scaled with the same type of characters of the same size. The instruments shall be 96 mm x 96 mm in size, with black scales on a white background. All current-operated instruments shall be protected against continuous over current up to 120% of nominal value and high current surges up to the fault rating of the circuit breaker Current transducers Each feeder or transformer panel shall have one current transducer connected to B of a metering CT. The output of the current transducer shall be used to drive the ammeter and then be connected to the SCADA RTU for remote indication. The approved current transducers are specified in EP SP. State of NSW through Transport for NSW Page 24 of 59

25 22.2. Voltage transducers A voltage transducer shall be connected to each VT and connected to the SCADA RTU for remote indication. The approved voltage transducers are specified in EP SP Ammeters Ammeters shall have two scales that are essentially linear. The main scale shall allow for 120% of the primary current rating of the current transformer and the second scale shall be equivalent to the main scale divided by 5, to allow reading of lower currents. A pushbutton fitted to the front of the ammeter shall activate the minor scale. The current transformer ratio shall be clearly marked on the face of the ammeter. The accuracy of ammeters shall be 3% or better and shall be stated in the technical schedule provided in Appendix F Voltmeters Voltmeter shall have analogue indication with scales that have an indicating range of 80% to 120% of the nominal system voltages. Where voltmeters that have a nominal range from 0% to 120% are required, this will be specified at the time of order. The nominal voltage shall be marked in red on the scale Watthour meter kwh meters shall be three phase, with pulse output. The pulse output rate shall be 10 per kwh. Where required for revenue metering the kwh meter shall be connected to a metering CT of suitable rating and accuracy class. 23. Busbar and circuit protection Protection schemes shall be in accordance with EP SP. The specific protection schemes for a switchboard are specified in the protection concept which is issued at time of switchboard procurement. State of NSW through Transport for NSW Page 25 of 59

26 23.1. High impedance bus zone protection When a high impedance unit protection scheme is used, the associated components such as protection relay, MTM, test block are to be located within one of the end panels that will be nominated at time of order Internal arc fault detection scheme An alternative to the traditional high impedance scheme is subject to an approval by the ASA. If approved, this system is the preferred scheme. If offered as an alternative to the high impedance scheme the complete system description shall be provided during tender for assessment Feeder protection The protection for feeders consists of overcurrent and earth fault protection and line differential protection at strategic locations shall be required. The protection scheme shall be specified in the protection concept which is required at time of switchboard procurement System transformer protection The relays and associated equipment for the protection of system transformers are normally located with the protection and control equipment for the higher voltage winding. The 11 kv circuit breaker panel for a system transformer shall be configured for connection to the required protection equipment located elsewhere. The neutral leakage relay is normally located on the 11 kv panel Distribution transformer protection The protection functions required for distribution transformers shall be implemented within the 11 kv panel. Inputs from gas relays or gas over pressure voltage free contacts, low voltage equipment voltage free contacts and high temperature RTDs inputs shall form part of the tripping circuit of the circuit breaker. EP SP defines two schemes for distribution transformers. Primary protection is a transformer differential scheme, with overcurrent and earth fault protection as backup. Primary protection is overcurrent and earth fault protection with no backup. State of NSW through Transport for NSW Page 26 of 59

27 Where a differential scheme is required, terminals shall be provided for the connection of current transformers on the secondary side of the transformer and the protection equipment shall provide a trip output to trip the low voltage circuit breaker. 24. SCADA indications and controls The SCADA alarms from equipment are implemented by a combination of hard wiring and using the serial link on the electronic protection relays. The serial communication port on all electronic protection relays within a switchboard shall be connected together and wired to a terminal strip for connection to the SCADA RTU. Refer to EP SP for further SCADA alarm requirements Binary indication and ACCB control Certain information is critical for system operation and shall be independent on the protection relay or communication link to the RTU. Table 7 details the SCADA alarms and control that are required to be hard wired to the RTU. Table 7 - SCADA alarms and control Hard wired I/O Point Description. Circuit breaker (Open, Closed) Isolator position (Open, Closed) Earthing switch position (Open, Closed) Circuit breaker alarms (example: spring charge motor) Trip circuit supervision alarms Gas/vacuum monitoring alarms Protection relay watchdog alarms Bus zone trip ACCB Open Control ACCB Close Control Hard Wired Analogue indication The following analogue indications shall be provided to SCADA: circuit current (B phase) for each circuit breaker bus voltage (at least 1 phase ) for each switchboard State of NSW through Transport for NSW Page 27 of 59

28 Current transducers shall be provided to allow monitoring of primary circuit currents by SCADA. Transducers shall be connected to a dedicated metering CT on B phase. Refer to Section 22.1 and Section Controls The SCADA RTU provides voltage free contacts which close for a maximum of 2 seconds for the following control functions: circuit breaker Open (trip) circuit breaker Close The SCADA RTU voltage free contacts have a maximum current rating of 1 A. Interposing relays are to be provided for the SCADA initiated ACCB close and ACCB trip. Refer to Section for additional details. The disconnector and earthing switch are manually operated and do not require SCADA control. State of NSW through Transport for NSW Page 28 of 59

29 Appendix A - Switchboard configurations Appendix A specifies the configuration requirements for the switchboards and switchgear. A.1 Switchboard configurations Most of the switchboard configurations applicable to the RailCorp network are detailed in Appendix B. Each switchboard shall be designed and manufactured specifically for each site within the following constraints: the switchgear functional units shall be assembled into switchboard panels each switchboard shall include a bus bar voltage transformer (VT) standard circuit breaker functions are feeder, system transformer, distribution transformer, tie (bus) and bus coupler switchboards with single bus tie panels shall have the bus tie at one end of the switchboard Switchboards with two bus tie panels shall have the bus tie panels at opposite ends of the switchboard. The position of each functional unit will be specified at time of order in accordance with the approved for purchase operating diagram. Where required for 11 kv network reasons, more than one switchboard may be required in a substation. Such switchboards would normally be physically separated to reduce the risk of one event damaging both. Switchboards are interconnected by a tie cable through a bus tie circuit breaker at each end of the tie cable. This is the preferred bus sectioning arrangement at a substation location. The cable tie requires a high impedance unit protection scheme. Where space or building constraints (example, cable ducts) exists, a bus coupling circuit breaker arrangement may be required for the busbar sectionalising function. However, this is not a preferred configuration. A.1.1 Switchboard panel configuration codes Table 8 provides the switchboard panel configuration and their codes. Table 8 - Switchboard panel configuration codes Switchboard panel configuration Bus tie cable circuit breaker: switchgear code Feeder circuit breaker: switchgear code System transformer (incomer) circuit breaker: switchgear code Codes T F ST State of NSW through Transport for NSW Page 29 of 59