DESIGN PRACTICE NOTE DESIGN/REVIEW REQUIREMENTS FOR TRACTION BONDING PLAN

Transcription

1 Approval Amendment Record Approval Date Version Description 01/04/ Initial Issue under MTM PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 1 of 7

2 Table of Contents 1. Purpose Scope Abbreviations and Acronyms Definitions and Responsibilities Background The Issue MTM Requirements Related Documents References and Legislation Appendix A: Additional Clarification of Traction Power Bonding Appendix B: Additional Clarification of Signalling Impedance/Cross Bonding... 7 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 2 of 7

3 1. Purpose The purpose of this document is to clarify MTM requirements relating to the design and installation of track bonding to ensure that both signalling and traction return current functionalities are achieved safely. 2. Scope This document applies to the design and installation of track bonding on the Infrastructure Lease for maintenance, renewals and project works. The scope has two parts being: the process to be followed by designers, design reviewers and installers; and, the technical requirements to be incorporated into the design and installation. 3. Abbreviations and Acronyms VRIOGS Victorian Rail Industry Operators Group Standards ARO Accredited Rail Operator MTM Metro Trains Melbourne 4. Definitions and Responsibilities The following persons are to note and comply with the terms of this Design Practice Note; Signal Designers o To incorporate requirements into all new designs Project Managers o To ensure requirements are incorporated into all design scope of works. Electrical Network Staff Signal Maintenance Network Asset Managers Signal Design Reviewers Signal Design Approvers Traction Power Engineer To review and approve. Traction Bonding Plan means Track Circuits, Bonding and Signalling Apparatus Plan. 5. Background The Track Circuits, Bonding and Signalling Apparatus Plan is a vital safety critical drawing which identify the types, length, locations of track circuits, insulated rail joints, rail bonding, connection, cable routes, positioning of cable track crossing, cable pits, layout of points, positioning of signals, train stops, TPWS and, where appropriate, the axle counters. This plan also identifies the exact positioning of equipment boxes which permits an opportunity to assess maintenance access to equipment along the corridor. PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 3 of 7

4 The rails are used for the return path for the 1500 V DC power for the trains. The bonding for traction return current is essential for the protection of personnel from electrical shock and the protection of the overhead wiring asset. The requirements for designing and installation of bonding from signalling and electrical traction perspective are clearly spelt out in VRIOGS 010.7, VRIOGS 012.0, VRIOGS 012.1, VRIOGS and Standard Drawing STD_G0097. MTM Standard MEST , Track Bonding For Signalling And Traction Return Current will supersede the VRIOGS and Standard Drawing as specified on its issue and at that time this Design Practice Note will be revised accordingly. 6. The Issue In general the concept of bonding from a signalling perspective is understood and compliant with the requirements contained within VRIOGS 010.7, VRIOGS 012.0, VRIOGS 012.1, VRIOGS and Standard Drawing STD_G0097. Signalling designers are required to fulfil the requirements relating to traction power contained within VRIOGS and Standard Drawing STD_G0097 when designing bonding systems and in some of the cases this has become a major concern and a serious safety risk, compromising the protection of the 1500 V overhead wiring. Confusion exists between the bonding requirements for a substation and for a tie station. In both cases the provisions of VRIOG and Standard Drawing STD_G0097 shall be complied with. During the design phase, The Track Circuits, Bonding and Signalling Apparatus Plan is not being reviewed by a Traction Power Engineer to ensure compliance with VRIOG 10.7 and Standard Drawing STD_G0097. A recent incident occurred where no protection for the 1500 V overhead wiring was considered as part of the design in accordance with VRIOG and Standard Drawing STD_G0097. The issue was only identified by MTM at the time of the final commissioning. It is essential that any issues associated with non compliance to VRIOG 10.7 VRIOGS 012.0, VRIOGS 012.1, VRIOGS and Standard Drawing STD_G0097 shall be identified prior to the design release for final review. 7. MTM Requirements From the date of this Design Practice Note the following procedure shall be adhered to; A) A Competent Signal Designer shall complete a traction bonding plan design as per the requirements of VRIOG 10.7, VRIOGS 012.0, VRIOGS 012.1, VRIOGS and Standard Drawing STD_G0097. Assurance shall be provided that all the requirements of the Accredited Rail Operator s (ARO s) Safety Management System, including operational and functional requirements and the appropriate standards, have been met. B) The design shall be Independently reviewed for its functionality, maintainability, reliability, constructability and compliance with the requirements of VRIOG 10.7, VRIOGS 012.0, VRIOGS 012.1, VRIOGS and Standard Drawing STD_G0097 by the contractor from both a signalling and traction power point of view. The Contractor shall provide clear certification to the ARO as an evidence for the proof of engineering. PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 4 of 7

5 C) The design is to be released to MTM Engineering for the purpose of the ARO s design review process. MTM Signal Engineers shall ensure that overall Safety in Signalling Design and Quality Assurance is considered by the Contractor. MTM Signal Engineers shall also ensure that compliance to relevant standards through the MTM design review process has been considered. The design shall also be reviewed by a MTM Traction Power Engineer to ensure compliance to VRIOG 10.7 and Appendix A including other associated system requirements from a traction power point of view. D) Upon approval by MTM Engineering the design shall be checked against any existing DC circuit breaker settings to ensure protection of the 1500 volt distribution network is included. E) All relevant parties shall then be informed that the design has been approved prior to release. (Issued for Construction) Refer to Appendix A and Appendix B of this document for further clarification to standards. Note: If at any stage, it has been deemed that the process in Section 7 has not been followed and/or the design has been identified to not comply with the requirements of VRIOG 10.7, VRIOGS 012.0, VRIOGS 012.1, VRIOGS and Standard Drawing STD_G0097, the design shall be rejected and returned to the Contractor for review, correction and re-submission. 8. Related Documents MEST Engineering Standard Design Traction Substations and Tie Stations VRIOGS Track Bonding, Track Circuit Connections and Traction Interfaces VRIOGS Victorian Signalling Principles VRIOGS Standard for Signalling Design and Documentation VRIOGS Specification for Signalling Supply, Construction and Installation Standard Drawing STD_G References and Legislation AS/NZS 3000 Electrical Wiring Rules AS 2067 High Voltage Installations ASNZS Electrical installations - Selection of cables EN Earthing, Bonding and the Return Circuit PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 5 of 7

6 10. Appendix A: Additional Clarification of Traction Power Bonding. (a) Electrical Traction Substations/ Tie Stations: - In principle the bonding requirements from inside the substation/tie station building to the rail are the same; both require a connection to the rails for protection circuit settings and operational safety. The only difference is in the cross-sectional area and the number of bonding cables required. Substations require the above bonding to allow, The operation of circuit breaker control circuits, requiring minimal DC currents Safety earthing of circuit breaker cubicles Traction load currents of amps magnitude to return to the supply point Tie stations A tie station contains only circuit breakers that connect two different 1500V DC electrical sections together to provide electrical protection. The track bonding at tie stations is not designed to carry heavy traction return currents, the bonding is to allow; The operation of circuit breaker control circuits (as in substations) Safety earthing of circuit breaker cubicles (as in substations) The bonding also covers short duration (milliseconds) short circuit fault currents should an internal fault occur on the tie station DC switchgear. Bonding from the Impedance bonds to the substation negative pillars (and the rails), or from the impedance bonds direct to substation buildings must be by means of 95 mm 2 aluminum conductors unless written approval is given in the form of a Standard Waiver. (b) Track side bonding In all instances, unless written approval is given in the form of a Standard Waiver, 300 mm 2 aluminum cables shall be used for; Connection to rail from impedance bonds Current equalizing jumpers between rails Voltage equalizing jumpers between tracks Power bonding around any special work or junctions The location and other requirements are clearly spelt out in VRIOG 10.7 and the Standard Drawing STD_G0097 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 6 of 7

7 11. Appendix B: Additional Clarification of Signalling Impedance/Cross Bonding Track Circuits, Bonding and Signalling Apparatus Plan should also cover the Impedance and Cross bonding information unless produced as a separate drawing. The principles and the detail of the traction bonding, Impedance and Cross bonding to be followed is as per MTM Standards on Traction Bonding along with all relevant VRIOGS. Positioning of airgaps should also be shown in the Track Circuits, Bonding, and Signalling Apparatus Plan. Necessary site correlation is to be undertaken prior to the alteration of the effected design. A Correlation report is to be submitted to the Engineering Group along with the Track Circuits, Bonding, Signalling Apparatus Plan for review and audit. PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 7 of 7