ep 03 01 40 00 sp - rectifier transformer - transport … · 7.2.15 marshalling box ... the...

Engineering Specification Electrical

Engi

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ing

Spec

ifica

tion

EP 03 01 40 00 SP

RECTIFIER TRANSFORMER

Version 3.1

Issued December 2012

Owner: Chief Engineer, Electrical

Approved by:

Neal Hook Chief Engineer Electrical

Authorised by:

Neal Hook Chief Engineer Electrical

Disclaimer This document was prepared for use on the RailCorp Network only. RailCorp makes no warranties, express or implied, that compliance with the contents of this document shall be sufficient to ensure safe systems or work or operation. It is the document user’s sole responsibility to ensure that the copy of the document it is viewing is the current version of the document as in use by RailCorp. RailCorp accepts no liability whatsoever in relation to the use of this document by any party, and RailCorp excludes any liability which arises in any manner by the use of this document. Copyright The information in this document is protected by Copyright and no part of this document may be reproduced, altered, stored or transmitted by any person without the prior consent of RailCorp.

UNCONTROLLED WHEN PRINTED of 36

RailCorp Engineering Specification — Electrical Rectifier Transformer EP 03 01 40 00 SP

© RailCorp of 36 Issued December 2012 UNCONTROLLED WHEN PRINTED Version 3.1

Document control

Version Date Summary of change December 2007 Last Technical Review

3 May 2010 Application of TMA 400 format 3.1 December 2012 Add Appendix C - Requirements for Technical Aspects of

Tender Evaluation



Contents

1 Introduction .............................................................................................................................6 2 Scope and Application ...........................................................................................................6 3 References...............................................................................................................................6 3.1 Code of Practice........................................................................................................................6 3.2 RailCorp Engineering Standards ..............................................................................................6 3.3 Australian Standards.................................................................................................................7 3.4 International Standards Organisation .......................................................................................7 3.5 American National Standards Institute......................................................................................7 3.6 Drawings ...................................................................................................................................7 4 Background .............................................................................................................................7 5 Functional Characteristics.....................................................................................................8 5.1 General......................................................................................................................................8 5.2 Whole-of-Life Cost ....................................................................................................................8 5.3 Interchangeability ......................................................................................................................8 6 Performance Characteristics .................................................................................................9 6.1 General......................................................................................................................................9 6.2 Sound Level ..............................................................................................................................9 6.3 Electrical....................................................................................................................................9

6.3.1 Characteristics ...........................................................................................................9 6.3.2 Windings ..................................................................................................................10

6.4 Ambient Conditions .................................................................................................................10 6.5 Overload Conditions................................................................................................................11 6.6 Harmonics ...............................................................................................................................11 6.7 Fault Level and Protection ......................................................................................................12 6.8 Electrical and Temperature Monitoring ...................................................................................12 7 Technical Characteristics.....................................................................................................13 7.1 Core.........................................................................................................................................13

7.1.1 Core Material ...........................................................................................................13 7.1.2 Winding Material ......................................................................................................13 7.1.3 Core Construction....................................................................................................13

7.2 Tank ........................................................................................................................................13 7.2.1 Limiting Dimensions.................................................................................................13 7.2.2 No structural failure..................................................................................................13 7.2.3 Welds.......................................................................................................................14 7.2.4 Accumulation of water .............................................................................................14 7.2.5 Accumulation of gas ................................................................................................14 7.2.6 Access to bushing and core connections ................................................................14 7.2.7 Tank Earth ...............................................................................................................14 7.2.8 Burrs ........................................................................................................................14 7.2.9 Drain valves .............................................................................................................14 7.2.10 Provision for temperature measurement devices....................................................14 7.2.11 Cable Cleats (HV Cable entry type only).................................................................15 7.2.12 Pressure Relief Device ............................................................................................15



7.2.13 Lifting Attachments/Wheels .....................................................................................15 7.2.14 Mounting plates .......................................................................................................15 7.2.15 Marshalling Box .......................................................................................................15 7.2.16 Alarm and Indication Contacts.................................................................................16 7.2.17 Surge Arrester Mounting Plate (HV Bushing Type only) .........................................16 7.2.18 Cable Tray ...............................................................................................................16

7.3 Conservator.............................................................................................................................16 7.4 Radiators.................................................................................................................................17 7.5 Terminal Arrangements...........................................................................................................17

7.5.1 HV Bushing Terminals .............................................................................................17 7.5.2 HV Cable Connected Terminals ..............................................................................17

7.5.2.1 33kV cable connection interface ..............................................................17 7.5.2.2 66kV cable connection interface ..............................................................18

7.5.3 LV Bushing Terminals..............................................................................................18 7.5.4 Neutral Bushing (HV winding) .................................................................................18

7.6 Tappings and Tap-Changer ....................................................................................................19 7.6.1 Tappings ..................................................................................................................19 7.6.2 Off-Circuit Tap-Changer ..........................................................................................19 7.6.3 Tap-changer control.................................................................................................20

7.7 System Earthing......................................................................................................................20 7.8 Winding and Oil Temperature Indicators ................................................................................21 7.9 Fibre optic temperature sensor ...............................................................................................21 7.10 Gas and Oil Actuated Relays..................................................................................................21 7.11 Oil ............................................................................................................................................22 7.12 Finish.......................................................................................................................................22 7.13 Breather...................................................................................................................................22 7.14 Rating Plate.............................................................................................................................22 7.15 Provision for Safe Access .......................................................................................................23

7.15.1 General ....................................................................................................................23 7.15.2 Guard Rails..............................................................................................................23 7.15.3 Ladder Access Point................................................................................................23 7.15.4 Fall Arrest Anchor Points .........................................................................................23 7.15.5 Documentation of safe systems of work..................................................................23

8 Integrated System Support Requirements.........................................................................24 8.1 Integrated Support Objectives ................................................................................................24 8.2 Equipment supplier deliverable...............................................................................................24 9 Tests.......................................................................................................................................25 9.1 Routine tests ...........................................................................................................................25 9.2 Type tests................................................................................................................................25

9.2.1 Sound level test: ......................................................................................................25 9.2.2 Doble power factor test:...........................................................................................25 9.2.3 Temperature rise test:..............................................................................................26 9.2.4 Lightning impulse test: .............................................................................................26

9.3 Special Test ............................................................................................................................26 10 Data Set associated with the Equipment............................................................................26



10.1 Drawings and Information .......................................................................................................26 10.2 Test Results ............................................................................................................................27 10.3 Life Cycle Costing ...................................................................................................................27 10.4 Technical Schedule.................................................................................................................27 Appendix A Technical Schedule ...............................................................................................28 Appendix B Request for Tender Checklist...............................................................................34 Appendix C Requirements for Technical Aspects of Tender Evaluation .............................36



1 Introduction This document details the whole-of-life performance requirements for outdoor ONAN 3 winding rectifier transformers suitable for use with the uncontrolled series full wave bridge 12 pulse rectifiers (Technical Maintenance Code EP 03 02 30 00) used in the RailCorp electrical network. It provides all necessary information to ensure that the rectifier transformers are electrically suitable for use with the RailCorp high voltage and 1500 V DC networks. It covers primary voltages of 33 kV and 66 kV and has secondary voltages of 600 V.

The rectifier transformer is used to supply electrical power to a traction load that has a different load profile to a standard power transformer.

In accordance with the philosophy of the RailCorp system wide spares policy for major equipment some specific clauses have been included in this document to ensure that a new rectifier transformer will meet particular physical requirements necessary for the direct replacement of existing rectifier transformers.

2 Scope and Application The rectifier transformer specified in this document is not suitable for use with the full wave bridge or 6 or 12 pulse half-wave rectifiers that have also been used in the RailCorp network. It is also not suitable to be used for a standard power transformer (Technical Maintenance Code EP 02 00 00 00).

The requirements of this document apply when a new rectifier transformer is installed in a RailCorp substation with a suitably specified rectifier and other equipment.

The release of this document will not affect the operation or maintenance of existing rectifier transformers currently in service in the RailCorp network.

3 References The following documents are either referenced in this standard or can provide further information.

3.1 Code of Practice

3.2 RailCorp Engineering Standards AM 99 95 PM RailCorp Maintenance Requirements Analysis Manual EP 00 00 00 12 SP Electrical Power Equipment – Integrated Support Requirements EP 00 00 00 13 SP Electrical Power Equipment – Design Ranges of Ambient

Conditions EP 00 00 00 15 SP Common Requirements for Electric Power Equipment EP 02 00 00 01 SP Transformer Loss Evaluation EP 03 00 00 01 TI Rectifier Transformer & Rectifier Characteristics EP 03 02 30 00 SP Semiconductor 12 Pulse Series Bridge Rectifier EP 12 10 00 10 SP System Substation Earthing EP 20 10 00 01 SP 1500 V DC Cable Ratings EP 90 20 00 01 SP 1500V DC Equipment Current Ratings



3.3 Australian Standards AS 1265:1990 Bushings for alternating voltages above 1000 V AS 1627.4:2002 Metal Finishing – Preparation and pre-treatment of

surfaces – Abrasive blast cleaning AS 1657:1992 Fixed platforms, walkways, stairways and ladders –

Design, construction and installation AS 1767.1:1999 Insulating Liquids – Specification for unused mineral

insulating oils for transformers and switchgear AS/NZS 1891.4:2000 Industrial fall-arrest systems and devices - Selection, use

and maintenance AS 2374 Series Power Transformers AS 2374.6:1994 Power transformers - Determination of transformer and

reactor sound levels AS 2700:1996 Colour Standards for general purposes AS/NZS 4680:1999 Hot-dip galvanised (zinc) coatings on fabricated ferrous

articles AS 60146:2002 Semiconductor converters Part 1.3 General requirements

and line commutated converters – transformer and reactor

3.4 International Standards Organisation 8501.1:1988 Preparation of steel substrates before application of paint

related products – visual assessment of surface cleanliness

3.5 American National Standards Institute BSR/IEEE C57.12.90 1999 Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers

3.6 Drawings EL0269498 General Substations, 33kV rectifier transformer basic configuration

requirements arrangement. EL0269499 General Substations, 66kV rectifier transformer basic configuration

requirements arrangement. EL0269500 General Substations, rectifier transformer tapchanger control circuit

schematic. EL0047995 Rectifier transformer remote control off-load tapchanger logic

sequence diagram for ASP motorized tapchangers.

4 Background Rectifier transformers are power transformers used to convert high voltage (33 kV or 66 kV) AC supply to AC voltages with smaller magnitude and varying phases, suitable as inputs to the rectifiers. The type of rectifier being used determines the rectifier transformer low voltage connections. There are 4 types of rectifiers in the RailCorp electrical network with the most common being the series full wave bridge. The rectifier transformer low voltage windings for this type of rectifier are two 600 V windings, one connected in delta and one in star. The rectifier transformer specified in this document is only suitable for use with series full wave bridge rectifiers, not for use with the full wave bridge, 6 or 12 pulse half wave rectifiers that have also been used in the RailCorp network.



5 Functional Characteristics

5.1 General The rectifier transformer will be protected by instantaneous AC overcurrent and earth fault protection that will trip the AC circuit breaker. The AC protection relays are not part of the scope of supply for the transformer manufacturer.

The transformer manufacturer is to supply:

• A Buchholz relay is to be supplied and fitted • A remotely controlled, motorised, off-circuit tap changer • Fibre optic sensors and controller interface • Electrical thermal model including verification against temperature rise testing and

fibre optic sensors • All other components and accessories specified herein other than items shown as

optional in Appendix A.

Where not specifically detailed in this specification the transformers shall be in accordance with the AS 2374 series – Power Transformers and AS 60146 General requirements and line commutated converters – transformers and reactors.

5.2 Whole-of-Life Cost The selection of the most suitable rectifier transformer must be made on the basis of minimising the whole-of-life cost. The following factors must be considered in determining this: -

• Cost of changes to the Technical Maintenance Plan & Service Schedules or the creation of new manuals & schedules.

• Cost of decommissioning and disposal. • Cost of installation. • Cost of inventory spares. • Cost of maintenance. • Cost of manuals. • Cost of modifications to other parts of the installation. • Cost of replacement parts. • Cost of special tools. • Cost of staff training. • Discount rate. • Electrical losses. • Environmental costs. • Initial purchase price. • Lifetime of equipment. • Reliability and cost of consequential damage after failure.

5.3 Interchangeability The 33 kV rectifier transformers shall comply with drawing EL0269498 to ensure physical interchangeability with other rectifier transformers of the same rating installed in substations in recent years.

The 66 kV rectifier transformers shall comply with drawing EL0269499 to ensure physical interchangeability with other 66kV rectifier transformers and strategic spares arrangements.

Rectifier transformer motorised tapchanger controls shall comply with drawing EL0269500.



6 Performance Characteristics

6.1 General Rectifier transformers shall be specifically designed for traction rectifier duty.

AS 60146 provides applicable requirements for heavy traction duty (class V1) oil cooled rectifier transformer for use with a 12 pulse, series bridge uncontrolled rectifier.

The normal operating condition for substations is for one rectifier to be off load and de-energised on standby. This de-energised condition can be for a period of months. The transformer shall be suitable for operation to full load specification when brought into service after such a period.

6.2 Sound Level The average level of audible sound caused by the transformer when measured in accordance with as AS 2374.6:1994, shall be the Standard Limit as defined in Appendix AA. Figure AA1, of this standard, at the factory.

6.3 Electrical

6.3.1 Characteristics The rectifier transformer shall have the following electrical characteristics:

Item 33 kV Requirements

66 kV Requirements

Primary 3 Number of phases

Secondary 1 x 3∅ delta, 1 x 3∅ star Primary 33 kVrms 66 kVrmsRated nominal voltages Secondary 600 Vrms x 2 Primary 36 kVrms 72 kVrmsSystem Highest Voltage Secondary 3.6 kVrms

Lightning Impulse 200 kVpk 325 kVpk

Primary Power Frequency 70 kVrms 140 kVrms

Lightning Impulse 5kV

Minimum Rated Insulation Level

Secondary Power Frequency 16 kVrms

Minimum Rated Power (continuous MVA) exclusive of harmonics

2.68 or 4.28 or 5.35 on HV 1.28 or 2.205 or 2.714 on LV’s Note: LV rating is slightly higher than ½ of the HV rating.

Rated Nominal Frequency 50 Hz.

Type Outdoor, Oil Immersed, Ground type.

Type of cooling ONAN. Connection vector symbol Yny0d1 or Yy0d1.



Reactance at rated current based on MVA (on Principal tap)

2.68 MVA

4.28 MVA

5.35 MVA

Minimum 8% 12% 14% Both LV windings shorted (Xsc)

Maximum 9% 13% 15%

Minimum 8.5% 12.5% 14.5% Either LV winding shorted, the other LV winding open circuit Maximum 9.5% 13.5% 15.5% Reactance between LV windings at transformer rating (close coupled) Maximum 2%

Winding temperature at which impedance measurements are made 75oC

LV voltage ratio Voltage ratio between star and delta LV is to match within 0.3%

Fault level

High Voltage-1500 MVA for 3 phase symmetrical fault Low Voltage – Limited by transformer impedance

Sound pressure level Refer to AS 2374.6, Appendix AA. Figure AA1, Standard limit.

High Voltage Winding Tappings - 4.5% to + 4.5% of nominal voltage in increments of 1.5%.

Table 1 - Electrical requirements

6.3.2 Windings The transformer shall be provided with a single primary winding and two secondary windings: one connected in star and one connected in delta. The delta winding can be a split delta to obtain a close coupled design. The secondary windings shall be of adequate rated power and voltage and they shall be arranged so that leakage reactance between them shall be small compared with the leakage reactance between secondary winding and primary, a 2% maximum at rated primary kVA - close coupled secondary’s.

The rectifier transformers are subject to frequent short circuits consistent with railway traction duty. The design is required to incorporate features to ensure all applied stresses do not result in unacceptable strains. Specifics of the design features to manage the frequent short circuits are to be fully detailed in Appendix A for assessment at tender stage.

Evidence supporting adequate short circuit strength shall be submitted with the tender and the final short circuit strength calculations shall be provided for design review.

6.4 Ambient Conditions The rectifier transformer shall be suitable for operation in the ambient conditions set out in EP 00 00 00 13 SP Electrical Power Equipment – Design Ranges of Ambient Conditions, as specified for outdoor equipment.



6.5 Overload Conditions The rectifier transformer shall be designed for a maximum winding temperature rise of 50 degrees when tested at nominal rating. This is in accordance with AS 60146 1.3 for duty class V1.

An allowance for harmonics in winding currents due to 12 pulse rectification shall be added to the overload requirements specified below. The rectifier transformer may be overloaded as per the conditions specified in the RailCorp document EP 90 20 00 01 SP. The rectifier transformer shall be capable of conducting 100 percent rated load continuously followed by any one of the overload conditions shown in Table 2. The equipment must meet each one of these individual overload conditions after temperature stabilisation at 100 percent load. The intent is not to apply the overload conditions consecutively.

% of continuous rating Duration of overload 100 Continuous 150 2 hours 200 30 minutes 300 1 minute 400 10 seconds

Table 2 - Rectifier Transformer Overload Ratings

The rectifier transformer can be expected to sustain overload conditions twice a day, once in the morning peak period and once in the afternoon peak period.

The location and value of the maximum winding hot spot temperature shall be determined by design and verified for the 100%, 150% and 200% loadings detailed in Table 2. All other information required to calculate the “thermal ageing of transformer insulation” in accordance with AS 2374.7 Section 2.6 shall also be supplied by the manufacturer. This hot spot temperature shall also be used for locating the fibre optic sensors. This information is to be kept with the maintenance data set.

6.6 Harmonics Guaranteed load loss values provided in the schedules shall be based on sinusoidal currents with the same r.m.s values in the line leads as would exist in normal operation at rated direct current if the rectifier overlap is disregarded and at the rated frequency. These values will be verified by transformer manufacturers factory testing.

Harmonics in the current waveform cause a multiplier effect on all eddy current losses within the transformer, and require suitable design allowances including cooling design, where it increases both the number of cooling ducts in the windings and the radiator area.

The minimum acceptable approach is provided in IEC61378-1 which defines an “eddy loss enhancement factor for windings”:

Fwe = ∑ (f.h)2

Where “f” is the per unit amount of harmonics at harmonic order “n” and ∑ f2 = 1

For LV windings use the 6 pulse figures from table in Section 9 of EP 03 00 00 01 TI. This shall be applied to the LV windings. Provide the enhancement factor in the schedule.

For HV windings, assume some harmonic cancellation and use the 12 pulse figures from Section 9.3 of EP 03 00 00 01 TI. Provide the enhancement factor in the schedule. Winding temperature indicators shall be based on hot spot gradient with harmonics above.



6.7 Fault Level and Protection The transformer shall be suitable for a supply from a high voltage system with a 3 phase symmetrical fault of up to 1500 MVA. The low voltage side of the rectifier transformer will have a fault level limited by the transformer impedance.

An alternating current circuit-breaker and alternating current instantaneous over-current and earth leakage relay set to operate at approximately 5 times full load of rectifier provide the primary protection. The AC clearing time may be as high as 0.15s for a DC fault condition. Operation of this protection will trip the AC circuit breaker only.

Back up protection on the AC circuit breaker will also be provided.

Rectifier cubicle frame leakage, reverse current and transformer Buchholz will trip both the AC and DC circuit breakers and ‘lockout’ the rectifier.

6.8 Electrical and Temperature Monitoring A thermal model shall be provided by the transformer manufacturer that will use the transformer primary current, thermal time constants, for example tank and winding time constants, and ambient air temperatures to predict Winding Hot Spot and Top Oil Temperature. The electrical/thermal equation shall be provided in differential form suitable to be solved by entering time varying values of HV current and ambient temperature as inputs. The output will be time varying profiles of Winding Hot Spot and Top Oil Temperatures and insulation ageing. The model is to be developed and provided by the transformer manufacturer in Microsoft Excel spreadsheet format.

This electrical/thermal model is to facilitate the prediction of the expected winding hot spot and top oil temperatures for varying load conditions and compare to specified thermal limits.

Real time values of ambient temperature and transformer HV input current will be measured, sampled and stored via SCADA. These time sampled values of current and ambient temperature will be input to the model. The winding hot spot and top oil temperature being measured by the transducers specified in Section 7.8 will be compared to the predicted values obtained by the model.

For future rectifier transformer loading (load growth) RailCorp will generate time varying transformer primary current from an electrical transportation simulator. The output of the simulator is primary current and ambient temperature with values at various time increments. Time increments can vary in the range from seconds to minutes. These values would be input to the model to be provided.

The thermal model is to be validated against results from the temperature rise testing specified in Section 9 and results from fibre optic sensors.



7 Technical Characteristics Common requirements for rectifier transformers as a whole and control equipment or assemblies used in the transformer, hardware and software aspects, Railcorp relay and circuit naming conventions and also the data set associated with this equipment shall comply with the requirements of EP 00 00 00 15 SP Common Requirements for Electric Power Equipment.

7.1 Core

7.1.1 Core Material Laminations shall be formed from the highest grade of cold rolled grain oriented silicon steel.

7.1.2 Winding Material HV windings must be manufactured from copper.

7.1.3 Core Construction • The core shall be designed and constructed to withstand without deterioration the

stresses imposed by service conditions, lifting, transport, handling and earthquakes.

• The interlamination and core bolt insulation shall not deteriorate from ageing, contact with transformer oil or service temperature.

• The core earth connection shall be brought out on bushings to a shorting link. The core earth connection shall be inserted in the core lamination to such a depth that the core clamp brings sufficient pressure to bear upon it.

• There shall be one connection only between the core and the earth bushing, the core connection of which shall be readily accessible during assembly. The purchaser intends to verify that the core to tank insulation is sound during the erection programme and accordingly the earth shall be designed to allow easy disconnection without risk of dropping loose components into the winding.

• Split ring washers, star washers and other types of locking washer shall not be used inside the transformer tank.

7.2 Tank

7.2.1 Limiting Dimensions The 33 kV tank, radiators and associated equipment arrangement shall satisfy the limiting dimensions shown on Drawing EL0269498.

For 66 kV rectifier transformer tank, radiators and associated equipment shall conform to limiting dimensions shown on Drawing EL0269499.

7.2.2 No structural failure The tank and accessories shall be so constructed that under transport and service conditions no structural failure or leakage of oil shall occur. The tank lid shall not distort on lifting.



7.2.3 Welds All permanent joints shall be welded, except the cover is to be bolted. All external welds shall be continuous. Caulking of defective welds is not acceptable.

7.2.4 Accumulation of water The tank and accessories shall be designed to prevent accumulation of water.

7.2.5 Accumulation of gas The internal surfaces of the tank shall be such as to prevent the accumulation of gas. All gas generated within the tank shall find an easy route to the Buchholz relay.

All unavoidable pockets in the lid such as bushing turrets shall have pipes fitted to their highest point to direct any gas collected into the main oil feed pipe from the conservator. All such gases shall collect in the Buchholz relay.

7.2.6 Access to bushing and core connections Hand-holes complete with covers shall be provided to allow all bushings to be replaced and the tap changer inspected without removing the main transformer cover.

The inspection covers and the tank lid shall be fitted with eyebolts for lifting.

Inspection covers shall be permanently labelled with details of the equipment that is accessible under the cover.

7.2.7 Tank Earth Two earthing studs with 2 x 14mm diameter hole suitable for connection of 2 x M12 bolt shall be located externally, near the bottom of the tank for connection to the substation earth grid.

7.2.8 Burrs Burrs and sharp edges on plates and tanks shall be removed.

7.2.9 Drain valves A drain valve 50 mm nominal bore pipe internal thread with flanged plug suitable for quick release fittings shall be fitted at the bottom of the transformer tank and the radiators to allow the oil and any moisture to be withdrawn.

An oil-sampling valve shall be provided at the bottom of the tank.

7.2.10 Provision for temperature measurement devices Suitable oil tight pockets shall be provided in the lid for top oil and winding temperature devices. The location of the pockets shall be carefully chosen to enable the measurements of the hottest top oil temperature. The design of the cover of the tank shall be such as to prevent the build up of pockets of still hot oil. The thermometer pockets shall be provided with a sealing cap to prevent moisture ingress and shall be of the external hexagonal head type with a gasket seal.



7.2.11 Cable Cleats (HV Cable entry type only) Unistrut support shall be provided below HV cable connection locations for attachment of cable cleats.

7.2.12 Pressure Relief Device Qualitrol XPRD (or other Railcorp approved alternative) extra high flow pressure relief device complete with directional discharge shield and highly visible semaphore shall be provided to minimise the build up of pressure within the main tank in the event of an internal fault. The discharge piping is to be directed to an appropriate site specific outlet.

The valve shall be rated such that, in the event of a fault within the transformer tank, no structural damage to the tank shall be incurred.

Alarm contacts shall provided integral with the pressure relief valve conforming to Section 7.2.16. These contacts shall be wired back to terminals in the Transformer Marshalling Box and installed in accordance with Section 7.2.15.

7.2.13 Lifting Attachments/Wheels Lifting attachments of appropriate capacity shall be provided on all devices that have to be removed for inspection purposes. This includes the tank top cover if this is capable of removal from the tank.

Lifting lugs and wheels or mounting plates fitted with anti vibration pads shall be provided for lifting\rolling the transformer full of oil into position. The lifting lugs shall be located so that the transformer can be lifted without removal or fouling of any part. The method and equipment required for lifting\rolling shall be determined and details included in the Equipment Manual however a design that necessitates slide rails being placed in discrete positions is not acceptable.

7.2.14 Mounting plates Mounting plates complete with anti vibration pads (such as Embelton Shearflex or similar) may be specified at time of order as an alternative to wheel mounting the transformer.

For this arrangement, plates shall be welded externally to the tank base at the designed load bearing areas to facilitate adequate support of the transformer via anti-vibration pads. The loading of the pads shall be appropriate for providing adequate noise isolation to the foundations. The surface area and layered construction shall be such that vibration attenuation at 100Hz of not less than 32 dBA is achieved (assuming infinite ground impedance). Required safety ground clearances to live exposed bushings must be an integral part of the plate/pad design.

7.2.15 Marshalling Box A marshalling box(s), with a suitable IP rating, shall be provided for connection of alarms and indications. All wiring shall be terminated on standard DIN rail terminals and labelled with non-ferrous labels. The terminals shall also be clearly labelled.

Others will supply cable glands, however a removable un-drilled gland plate of an approved size shall be supplied by the transformer manufacturer, located to permit cable entry from below.



7.2.16 Alarm and Indication Contacts For each alarm or indication a single voltage free changeover contact or one normally closed and one normally open contact shall be provided.

The contacts shall be suitable for making and breaking up to 100mA in a 125V-dc circuit or 250mA in a 50V-dc circuit. The contacts shall be suitable for switching relay coils and similarly inductive loads.

7.2.17 Surge Arrester Mounting Plate (HV Bushing Type only) Standard fittings shall be affixed to the tank for the mounting of suitable surge arresters adjacent to the HV bushings.

7.2.18 Cable Tray 100mm cable tray shall be provided attached to the top cover and side walls for the purpose of routing small wiring between equipment items. Alternatively, wiring can be tied by stainless steel ties to either “J” hooks or “towel rails” welded onto the tank.

7.3 Conservator A suitably sized conservator with the following accessories shall be fitted:

• A 50 mm nominal bore pipe internal thread with flanged plug suitable for quick release fittings shall be fitted above the maximum oil level of the transformer tank for filling purposes.

• The main oil feed pipe to the tank shall project through the bottom of the conservator by an amount sufficient to provide a sump with a volume of approximately 5% of the conservator volume. Flanged pipes of 50mm diameter shall be fitted at each end of the conservator so that oil may be completely drained and all sludge and foreign matter may be extracted by filtering. The pipes shall be fitted with 50mm valves.

• Internal surfaces shall be treated with an approved oil resistant coating sufficient to ensure that the conservator meets the specified design life criteria.

• A magnetic oil level gauge with alarm contacts is to be fitted (due to air bag conservator compatibility). Visibility of the oil level from ground level with the transformer in its installed position in the substation is required. Generally this means that the indicator should be visible from the High Voltage end of the transformer.

• A membrane (air bag) between the oil and air to prevent moisture in the air from contaminating the oil in the conservator. Air bag is to be Fujikura type FNH8-045 or an equivalent to be approved by Railcorp.

• The conservator base brackets shall be bolted to the main tank. • Access shall be provided to all compartments of the conservator to facilitate

cleaning. • Conservator shall be designed for operation over full duty cycle (as specified in

Section 6.5) over the ambient temperature range specified in Section 6.3.2 except that the maximum design temperature shall be not less than 2 degrees Celsius greater than the maximum temperature stated in Section 6.3.2 Calculations shall be provided at tender stage to confirm that the conservator will meet this requirement.

• A stop valve between the conservator tank and the Buchholz type relays • The conservator shall be arranged so that all air can be excluded from below the

membrane at the time of filling. • Lifting eyes shall be fitted to the conservator of sufficient capacity to allow removal

of a full conservator.



7.4 Radiators Galvanized radiators suitable for full vacuum, attached to the side of the tank via readily accessible isolating valves.

The main connection to the radiators shall be fitted with valves immediately adjacent to the tank to allow removal without lowering of the transformer oil level. Operation of the valves shall be possible when the transformer is in its installed position. Drain cocks shall be fitted to the lowest point to allow removal of oil from individual radiators independent of the transformer tank oil and other radiator sections.

The external surfaces of the radiators shall be hot dip galvanised to AS 4680. Minimum thickness of galvanising shall not be less than 84 micrometres.

Radiators shall be fitted with lifting eyes capable of supporting the combined weight of the radiator and oil.

Radiators shall be fitted with mounting points to allow future installation of cooling fans that will provide forced airflow through the fins.

7.5 Terminal Arrangements Connection to the primary terminals will be made by cables or bare conductor indicated in the Request for Tender. See Section: Appendix B RailCorp Standard EP 20 10 00 01 SP 1500 Volt DC Cable Ratings, Section 5.3 provides guidance on the preferred LV cable number and sizes. The design of the terminal arrangements shall be such as to minimise the mechanical loading of the connecting cables, including allowance for thermal expansion of the cables.

7.5.1 HV Bushing Terminals Where HV bushings are specified in the Request for Tender as the HV connection method the higher voltage and lower voltage terminal bushings shall be arranged on opposite sides of the transformer and in rows parallel with the major axis of the transformer in accordance with drawing number EL0269499.

All the terminal bushings shall be fitted with flat connecting palms, comply with AS 1265 for a normally polluted atmosphere and be solidly insulated.

Access to the neutral connection of the high voltage star connected winding shall be possible without the removal of any oil and also allow the testing of individual high voltage phase windings.

7.5.2 HV Cable Connected Terminals

7.5.2.1 33kV cable connection interface Where a 33kV HV cable is specified in the Request for Tender as the HV connection method a bolted, dead break separable, Tee shape connector suitable for interfacing with a 33kV, single core, 120mm2 XLPE CU cable is to be provided for each phase by the transformer manufacturer.

The cable screen is to be broken at the transformer and solidly connected to earth at the switchgear end of cable. The transformer connection is to be touch safe. Details of an approved type are provided below:

• HV bushing Euromold plug in type M400AR-3/GS (includes earth plate)


• Separable Tee connector Euromold type M400TB/G including all associated components necessary for a screen break cable termination to the copper XLPE cable: Tee connector housing, cable reducer, clamping screw, conductor contact, insulating plug and cap, field control mastic, silicone grease and wipers (to be provided by the transformer manufacturer). Site specific cable termination kit to be clarified at time of order of transformer.

Suitable mechanical and weather protection to the HV plug-in connector shall be incorporated in the design of the transformer.

7.5.2.2 66kV cable connection interface Where a 66kV cable is specified in the request for Tender as the HV connection method a bolted, separable, Tee shape connector suitable for interfacing with a 66kV, single core, XLPE CU cable is to be provided for each phase.

Currently Railcorp do not have any 66KV cable connected rectifier transformers. Details of an approved type shall be resolved at design review stage with the transformer manufacturer. The minimum requirement is that the connections shall be touch safe and configured similarly to the arrangement required for 33kV.

7.5.3 LV Bushing Terminals All rectifier transformers shall be equipped with appropriately rated LV bushings. LV bushings shall be equipped with Raychem bushing connection animal covers or equivalent.

It is important that the physical arrangement of the connections between the rectifier transformer and the rectifier power cubicle are aligned to avoid crossing of the 600V ac cables. The relationship of the connections is highlighted in Figure 1 below. For simplicity no other major equipment or components are shown.

Figure 1 - Rectifier AC Connections Diagram

7.5.4 Neutral Bushing (HV winding) Where required a neutral bushing shall be provided located on the upper surface of the transformer tank. Where HV bushings are provided the neutral bushing shall be grouped with the HV bushings. See Appendix A for details.




7.6 Tappings and Tap-Changer

7.6.1 Tappings High Voltage winding tappings at increments of 1.5% over the range –4.5% to + 4.5% of the nominal voltage (7 taps) shall be provided.

7.6.2 Off-Circuit Tap-Changer A remotely controlled, motor operated, tap-changer with visible position indicator shall be provided to change tappings in the high voltage winding.

Tapchanger is to be rated for the full overload requirements including harmonics as specified in Section 6.

The tap-changer shall be capable of changing taps with the primary circuit de-energised.

All leads and connections to fixed and moving contact assemblies shall be supported and adequately braced to withstand short circuit currents for which the transformer is designed. The tapping switch shall be capable of withstanding the overload characteristic specified in Section 6.5 Test certifications, proving continuous current, 3 second short circuit withstand current, and B.I.L. shall be provided.

All contacts shall be of the self-wiping and snap action type.

The design shall be such as to prevent the ingress of moisture in to, or the leakage of oil from, the tank.

Tapping switches shall be provided with mechanical end stops that prevent movement beyond an end position.

It shall be possible to clearly determine the tap position safely from the ground without isolating the transformer.

Taps are to be numbered one(1) to Seven(7) form highest input volts to lowest. Typical numbering is provided below in Table 3:

Off circuit switch position 33kV HV volts 66kV HV volts 1 34485 68970 2 33990 67980 3 33495 66990 4 33000 66000 5 32506 65010 6 32010 64020 7 31515 63030

Table 3 - Tap switch numbering



7.6.3 Tap-changer control The tap change control circuit shall operate at 125V DC power which will be supplied from the Substation 125V DC Distribution Board.

Signal contacts shall be rated for use at 125V DC.

Normal control of the tap changing operation will be from a remote location via the RailCorp SCADA (Supervisory) system, however, local operation via pushbuttons shall also be possible. A two position selector switch with positions “Local” and “Supervisory” shall be provided on the tap-changer control cabinet for selection of mode.

The tap-changer shall be designed to receive remote Enable, Raise and Lower commands as voltage signals at 125V DC positive, together with Common 125V DC negative. The Enable signal derived from a normally closed contact from the 33kV rectifier transformer ACCB will provide an input (interlock) to prevent tap changing in either mode when the 33kV ACCB is closed.

Enable will be a maintained signal, whilst Raise and Lower commands will be fleeting of 1 second duration. Maximum current available to activate each signal will be 1 A.

The tap-changer shall be designed to index one step at a time only, either up or down, when a remote Raise or Lower pulse is received.

Indication of the tap position shall be available to the remote operator, preferably via individual N/O contacts for each position of the tap-changer.

Provision shall be made for remote indication that the tap change sequence is in progress when the tap changer is changing position. This signal shall comprise a relay contact that is normally closed and which opens whilst a tap change is in progress. The actual tap change shall commence not less than one second after the indication signal goes to the “changing position” state.

A Fault signal shall also be available for remote indication and shall incorporate all fault conditions that may reasonably be monitored, together with loss of motor and control power supply. This signal shall be a contact that is normally closed and which opens upon fault.

The location of the tap changer control cabinet shall arranged such that the overall size of the transformer complies with Section 5.3.

The functionality and interfaces shall be consistent with Railcorp drawing EL0269500 General Substations, rectifier transformer tapchanger control circuit and auxiliary schematic diagram.

7.7 System Earthing The RailCorp 33 kV and 66 kV systems are not effectively earthed.

The secondary side of the transformer is not earthed under normal service conditions so that over-voltages due to the capacitances between windings and between windings and earth must be allowed for in the transformer design. The rectifier negative terminal is not deliberately earthed, but is normally close to earth potential and may be connected to earth under some conditions. See RailCorp Standard EP 12 10 00 10 SP System Substation Earthing.



7.8 Winding and Oil Temperature Indicators The following shall be provided:

• Top Oil Temperature indication contacts A, • Top Oil Temperature indication contacts B, • Winding Hot-spot Temperature indication contacts A, • Winding Hot-spot Temperature indication contacts B, • Winding Hot-spot Temperature local visual indicator • Winding Hot-spot Temperature remote analogue transducer • Top Oil Temperature remote analogue transducer.

The temperature at which each set of indication contacts operate shall be independently adjustable over the range 70OC to 150OC in 10°C increments and it shall be possible to readily set the operating point within +/- 2OC without the need for additional set up instruments. The instrument shall be capable of operating in ambient conditions as specified in EP 00 00 00 13 SP Design Ranges of Ambient Conditions, for auxiliary equipment located near heat emitting equipment.

It is intended that one set of indication contacts will be used to provide remote alarms of abnormal temperatures and that the second set of contacts will be set to operate at a higher temperature and will be used to trip the transformer AC circuit breaker.

Winding Hot-spot Temperature local visual indicator shall be provided with a re-settable maximum indicator and shall have an accuracy not inferior to +/- 2OC

Winding Hot-spot and Top Oil Temperature remote analogue transducers shall provide a 0-20mA output and shall have accuracy not inferior to +/- 2OC. The transducers shall be suitable to operate from the substation auxiliary supply voltage as nominated in the request for tender. See Appendix B. It is intended that the output of the transducer will be connected to the SCADA system.

The device shall be fixed on a flexible mounting to minimise the effect of transformer vibration. All necessary wiring installed in accordance with Section 7.2.15.

7.9 Fibre optic temperature sensor Fibre optic temperature monitoring fibres, tank oil interface penetrator (3/8” NPTS), fibre patchcords terminated into a marshalling box, to monitor top oil and winding hot spot temperatures are to be provided.

A minimum of four fibres (two for HV and two for LV) shall be allocated to winding hot spot measurement. The fibre optic sensor shall be Fiso type TPT-32. Fibre sensors are to be used with a Nortech direct winding temperature monitoring system; alternatives to this will require approval by Railcorp.

Provision of the Nortech monitoring system is optional.

7.10 Gas and Oil Actuated Relays A gas and oil actuated relay of the Buchholz type shall be provided.

The relay shall be equipped with two elements: one operating in the event of a surge in the oil and the other when gas accumulates slowly within the transformer. For each element, a set of contacts shall be provided. All necessary wiring installed in accordance with Section 7.2.15.

Provision shall be made to enable gas from the relay to be sampled at ground level.



7.11 Oil Corrosive sulphur free Nynas Transformer oil - Nytro Libra compliant with AS 1767.1:1999 shall be used.

In order to comply with NSW Environment Protection Agency guidelines for PCB free materials the transformer oil must contain less than 2 milligrams per kilogram of PCB.

Should the PCB content exceed 2 mg/kg then the oil shall be "treated" as necessary to reduce the PCB level below 2 mg/kg. (A tag indicating that the oil contained within is PCB free shall be attached permanently to the transformer.)

7.12 Finish All external surfaces shall have welds made smooth, rough edges rounded and weld splatter removed.

The transformer tank and cover shall remain corrosion free for the life of the transformer.

The internal and external surfaces shall be prepared and the coating applied strictly in accordance with the manufacturer’s instructions. Galvanising of surfaces in contact with oil is not permitted.

The minimum preparation is abrasive blast cleaning all steel surfaces in accordance with AS 1627, part 4 to ISO 8501-1:1988, “Preparation of steel substrates before application of paints and related products – visual assessment of surface cleanliness”, Class 2.5. The internal steel surfaces are to be painted with an oil resistant paint immediately after abrasive cleaning. The external steel surfaces painted with an inorganic zinc-rich paint immediately after abrasive cleaning. The preferred colour is storm grey, colour N° N42 in accordance with AS 2700.

When an existing transformer suffers damage to its finish, the repair shall be to the original standard of finish.

7.13 Breather A breather shall be provided for the air space above the membrane in the conservator. If the space has not been designed to be unaffected by moisture a de-hydrating breather shall be provided, sized to allow for humid air conditions. The breather shall be provided with an effective oil seal and an inspection window so that the colour of the crystals can be observed. It shall be possible to replace the crystals in a simple and straightforward manner that does not require de-energisation of the transformer for replacement. If a de-hydrating breather is not required, the breather shall be arranged to exclude insects from the conservator air space.

7.14 Rating Plate A rating plate conforming to the requirements AS 2374.1:1997 Power Transformers Section 7, Rating plates, made of brass or other approved material shall be firmly attached by means of screws at each corner to a bracket (the size of the rating plate) externally on the transformer enclosure. It is not to be attached to any removable cover. The rating plate shall include a diagram of connections, RailCorp specification number, date of manufacture and be located so that it can be read from ground level.



7.15 Provision for Safe Access

7.15.1 General Guard rails shall be provided around the perimeter of the top of the tank to facilitate safe access for installation and commissioning tasks, and all maintenance actions identified in the equipment manual on the top of the transformer. Where any required task is must be undertaken at a greater height such that it can not be carried out by a person standing on top of the tank within the hand rails anchorage points and other fixings suitable for an industrial fall-arrest system to permit a safe system of work for such tasks shall be fitted.

7.15.2 Guard Rails Guard rails shall comply with AS 1657

Guard-rails shall be de-mountable (bolted connections or similar) from the tank to facilitate transport of the transformer.

The toe-board and mid rail may be omitted form the area adjacent to the LV Bushings to provide clearance for the LV cables.

In the case of transformers fitted with HV bushings, the top rail, or top rail and mid rail, may be omitted adjacent to the HV bushings as necessary to provide the required electrical clearance.

7.15.3 Ladder Access Point A ladder access point shall be provided clear of radiators and low voltage bushings.

The ladder access point shall be clearly identified.

The ladder access point shall provide positive location and support for a portable extension ladder. A tie-off point shall be provided to secure the foot of a ladder placed at the ladder access point. A gate or similar shall be provided in the hand-rails at the ladder access point.

7.15.4 Fall Arrest Anchor Points If the use of an industrial fall-arrest system is required to facilitate any task that must be done by a person standing above the top of the tank, a safe system of work for all such tasks shall be designed and documented. The safe system of work shall comply with the requirements of AS/NZS 1891.4. Suitable fall arrest anchorage points shall be nominated. It is preferred that suitable structural elements are nominated as anchor points for use with an anchor sling of similar rather than the provision of dedicated fall arrest system anchor points.

7.15.5 Documentation of safe systems of work The maintenance manual shall include details of any safe systems of work required to facilitate any task that must be done by a person standing above the top of the tank.



8 Integrated System Support Requirements

8.1 Integrated Support Objectives The tenderer must establish and provide the information required to operate and maintain the equipment throughout its operational life, in a cost effective manner and to a level that is consistent with the planned operational performance and usage of the Rectifier Transformer.

This includes:

• Specifying Maintenance Requirements • Spares Support • Operations and Maintenance Manuals • Training, and • Support Equipment and Tooling

8.2 Equipment supplier deliverable The Integrated support requirements are a significant deliverable in the procurement of a new Rectifier Transformer. Manuals, training, documentation and other support deliverable’s shall be in accordance with EP 00 00 0012 SP Electrical Power Equipment – Integrated Support Requirements.



9 Tests

9.1 Routine tests Routine tests as listed in AS 2374.1 Section 10.1.1 and specified below shall be carried out on each transformer.

A transformer test report for each transformer shall include:

• Specific transformer details • Index of test results • Statement of measurement uncertainty for each test • Summary of routine tests: No load loss, load loss, winding resistance, dielectric

withstand, insulation resistance • Transformer ratio • Transformer winding resistance • Transformer insulation resistance • DLA • Transformer no load loss & current • Dielectric tests • Transformer load loss and short cct impedances: HV & (LV1+LV2 sht cct), HV &

(LV1 sht cct), HV & (LV2 sht cct) • CT tests: resistance, polarity, ratio • Tapchanger functional checks • Auxiliary circuits insulation test

In addition the following test shall also be carried out on each transformer-

• An extended No-Load Loss and Current Test in which the transformer shall be energised continuously at rated no-load voltage for at least six hours after which time the no-load watts and current shall be measured. If these losses are greater than those measured in the routine test, they shall be used in the evaluation of losses.

• After the transformer has been delivered to site and any oil added as may be necessary, the suppliers shall arrange for the oil to be tested for PCB content and a certificate issued to the Purchaser showing the PCB content.

9.2 Type tests Type tests shall be carried out on one transformer of a batch as follows-:

9.2.1 Sound level test: A sound level test in accordance with AS 2374.6

9.2.2 Doble power factor test: A Doble power factor test in accordance with Method II in I.E.E.E. Standard No. 262 (ANSI C57 12.90:1987). The measurement of power factor shall not exceed 0.5% at 20oC.



9.2.3 Temperature rise test: A temperature rise test in accordance with AS 2374.1 Section 10.1.2 for each of the overload conditions specified in Section 6.5 of this standard. In conjunction with the temperature rise test the fibre optic sensor is to be calibrated against temp rise test results.

Temperature rise test report to include: Calculations, shutdown curves for HV, LV1, LV2, amps+losses+amb temp+top oil temp+top pipe temp+bot pipe temp+ fibre sensor temp against time

9.2.4 Lightning impulse test: A full wave lightning impulse test as specified in AS 2374 Part 3 Section 6.2.2.

Type test certificates for each of these tests will be accepted where it can be demonstrated that the transformer supplied is of an identical design and manufacture to a previously type tested transformer.

9.3 Special Test A test is required to verify the transformer’s inductance referred to the 1500 V DC side when used with a 12 pulse rectifier in accordance with EP 03 02 30 00 SP Semiconductor 12 Pulse Series Bridge Rectifier.

10 Data Set associated with the Equipment The following data shall be supplied by the manufacturer and maintained for the rectifier transformers. This data will remain the property of RailCorp.

10.1 Drawings and Information The following drawings are required:

• Final Outline Drawing

Final outline drawings with full details and locations of all items. The outline drawings shall include the mass of individual items in the erected condition such as main tank and radiator bank.

• Foundation Drawings

Foundation drawings showing detail of base for the main tank and radiators if these are separately mounted.

• Schematic and Wiring Diagrams

Schematic diagrams of the transformer windings showing connections, tappings and tabulations of current and voltage rating of all windings.

Schematic diagrams of control of auxiliary systems.

Wiring diagrams: including Cable block diagram, Cable schedule and Cable termination schedule.

• Cabinet Layout

Layout drawing of marshalling cabinet showing details of all components.



• Rating Plate

Drawings of the rating plate required in Section 7.14. Details shown on these drawings must not vary from that shown on the plates fixed to the transformer.

• Internal Construction

Detailed construction drawings of internal arrangements of the transformer.

• Bushings and Cable Box Drawings

Full details of all bushings including profile drawings and full details the cable box where supplied.

• Winding Details • Fibre optic system

Full details identifying location of sensors, oil / tank penetration details, method of attachment within tank, component details and description of overall scheme operation and use.

10.2 Test Results The results of all tests, including routine, type, special, acceptance, periodic and corrective maintenance tests, shall be recorded and maintained.

Routine Tests certificates showing the results of each test performed shall be supplied in duplicate and electronically, in English, and maintained for the life of the transformer.

Type Tests certificates showing the results of each test shall be supplied in duplicate and electronically, in English, and maintained for the life of the equipment.

10.3 Life Cycle Costing All the data and assumptions pertaining to the determination of the whole-of-life cost calculations shall be recorded, including transformer loss calculations as detailed in EP 02 00 0 01 SP Transformer Loss Evaluation

10.4 Technical Schedule The information listed in the technical schedule of Appendix A, from the successful Tenderer, shall be maintained for each rectifier transformer.



Appendix A Technical Schedule The Tenderer shall supply the information listed in this Technical Schedule at tender stage, for each rectifier transformer.

Transformer Details

Rated primary voltage .………………............. V

Rated secondary voltage .………………............. V

Rated power of primary winding .………………............. MVA

Rated power of secondary star winding .………………............. MVA

Rated power of secondary delta winding .………………............. MVA

Connection symbol .……………….............

No-load current with rated voltage applied to the principal tapping .………………............. A

No-load current with 110% rated voltage applied to the principal tapping .……………….............

A

No-load loss .………………............. W

Load loss at 75°C .………………............. W

Thermal Time Constant – Tank .………………............. Hrs

Thermal Time Constant – Winding .………………............. Mins

Inductance referred to 1500V DC side (when used with a 12 pulse rectifier in accordance with EP 03 02 30 00 SP) .……………….............

mH

Impedance voltage at rated current and 75°C based on MVA

− With secondary No 1 short-circuited .………………............. %

− With secondary No 2 short-circuited .………………............. %

− With secondary windings short-circuited .………………............. %

Type of core steel - hot or cold rolled .……………….............

Brand or trade name and grade of core steel .……………….............

Maximum flux density on net cross-section of steel with rated volts at rated frequency applied to the centre tapping

− Limbs .………………............. T

− Yoke .………………............. T

Mean sound level .………………............. dB(A)

Continuous rating of tap-changer .………………............. A

Overload rating of tap-changer and information to show that it is capable of carrying the overload specified: .……………….............

Type of material used for windings

− HV .……………….............

− LV .……………….............



Type of insulation on windings .……………….............

Maximum dielectric stress on winding insulation .………………............. V/mm

Type of gasket material .……………….............

Transformer oil – provide data sheet

Transformer oil – provide details on compatibility with components, materials and insulation with regards to corrosive sulphur.

What levels of corrosive sulphur will be present at stipulated time intervals:

.……………….............

.……………….............

.……………….............

New 1 Year

10 Years

Type of Conservator Airbag .……………….............

Buchholz relay data sheet - to be provided by tenderer

Winding and Oil temperature indicator data sheet - to be provided by tenderer

Winding temperature CT details .……………….............

Protective treatment applied to tank:

− Internal surfaces .……………….............

− External surfaces .……………….............

Overall Dimensions

Extreme height from floor level .………………............. mm

Extreme height from floor level when stripped for transport .………………............. mm

Projected floor area .………………............. mm x .………………............. mm

Mass

Mass of transformer complete with oil .………………............. kg

Mass of transformer core and windings only .………………............. kg

Mass of windings only .………………............. kg

Volume of oil required to fill transformer, complete .………………............. Litres

Bushings

Higher Voltage Lower Voltage

Maker .………………....... .……………….......

Maker's type number .………………....... .……………….......

Materials .………………....... .……………….......

Continuous current rating .………………....... A .………………....... A

Number per transformer .………………....... .……………….......

Lightning impulse flashover voltage .……………….......

kVp .……………….......

kVp

Creepage distance .………………....... mm .………………....... mm


Minimum air clearance

between phases mm .………………....... .………………....... mm

phase to earth .………………....... mm .………………....... mm

Palm dimensions ......... mm x ...…... mm ......... mm x ...…... mm

Other particulars: ……………………………………………………………………………………. Temperature Rise

Temperature rise of transformer under the load conditions specified in Section 6.5

Windings Top oil

Full load .………………............. °C .………………............. °C

150% for 2 hours .………………............. °C .………………............. °C

200% for 30 minutes .………………............. °C .………………............. °C

300% for 1 minutes .………………............. °C .………………............. °C

400% for 10 seconds .………………............. °C .………………............. °C

Winding Hotspot Temperature

Maximum winding hot spot temperature at 40°C ambient when calculated in accordance with AS 2374:1997 under the load conditions specified in Section 6.5.

Full load .………………............. °C

150% for 2 hours .………………............. °C

200% for 30 minutes .………………............. °C

300% for 1 minutes .………………............. °C

400% for 10 seconds .………………............. °C

Reliability Data (use separate sheet if necessary):

Design Life Years .………………............. Failure Modes (for Early, Normal Life, & Wear Out periods) a) .……………….............

b) .……………….............

c) .……………….............

Mean Operating Hours Between Failures: a) .……………….............

b) .……………….............

c) .……………….............

Time to Repair: a) .……………….............

b) .……………….............


c) .……………….............



Drawings and Information to be submitted with the Tender

Outline Drawings

Fully dimensioned outline drawings showing all fittings, terminal arrangements, radiator equipment, tap changer equipment, marshalling cubicle, required maintenance access. The general arrangements and layouts are to be adhered to in the final design unless written approval is obtained from RailCorp.

Core Material Characteristics

Typical Curves Of Flux Density Versus Ampere Turns Per Metre For The Core Material

Core Information

Drawing and detailed description of core type, methods of making joints, insulation between laminations, treatment of edges, core bolt insulation and method of minimising hot spots in limbs.

Details of the proposed method of verifying core hot spot temperature.

Details of core earthing method.

Transformer design

Provide comprehensive details on transformer design for the following:

• Winding and short circuit design

Provide detailed design features of winding and winding supports to withstand frequent short circuit conditions associated with normal operation as a railway traction duty transformer.

• Overload allowances to comply with Section 6. • Harmonic assumptions, allowances and type testing methodology • Voltage ratio. Provide details on turns and error (mismatch) on LV voltages.

Temperature Indicators

A full description of temperature indicators and transducers including detailed design information on the type of pocket to be used.

Tap-Changer Details

A full description of the tap-changer proposed including type test certificates.

Other Information

Any other information considered necessary by the manufacturer.

Conservator sizing

Provide detailed calculations for the sizing of the conservator.

Fall-Arrest System

Provide details of the proposed method for the industrial fall-arrest system as required in Section 6.14.

Neutral HV connection

At some locations in the RailCorp network under contingency feeding arrangements it may be necessary to energise the 33kV network via a transformer having a Delta winding on the 33kV side. In such situations it is proposed to use a rectifier transformer to provide the earth reference for the 33kV network and it will be necessary to earth the star point of the primary winding.



Where specified in the Request for Tender, the neutral connection of the high voltage star connected winding shall be brought out on a suitable solidly insulated, terminal bushing fitted with a flat connecting palm, and complying with AS 1265 for a normally polluted atmosphere.

The neutral bushing shall be located on the upper surface of the transformer tank. Where HV terminal bushings are provided the neutral bushing shall be grouped with the HV bushings.

Although intended to allow the neutral point to be earthed when required, the neutral terminal will not normally be earthed.

If this option is implemented, this will be deemed to satisfy the requirement of the third paragraph of Section 7.5.1.

Alternatively the neutral connection may be brought out using HV cable connected, bolted dead break separable methods as specified in Section 7.5.2.

Calculations justifying the level of insulation provided when the neutral point is not earthed shall be supplied with the tender response.

Drawings showing the proposed arrangement for the neutral bushing shall be provided with the tender response.

Transformer Inductance Test

The proposed method to verify the transformer’s inductance referred to the 1500 V DC side when used with a 12 pulse rectifier in accordance with EP 03 02 30 00 SP Semiconductor 12 Pulse Series Bridge Rectifier.

Departure from Standard

Are there any departures from the requirements of this Standard?

* YES / NO

* If ‘YES’ Include details on separate sheet.

Special Delivery Requirements

Any special requirements that are envisaged for the safe delivery of the rectifier transformer to the specified site must be stated at Tender stage, for example, removal of bushings due to low bridge on delivery route. These costs shall be provided separately at Tender stage.

Options to be Priced at Tender

Stainless Steel Conservator

Conservator fabricated from Stainless Steel, Grade 316 if required to make the conservator air space above the membrane unaffected by moisture.

On load tap-changer.

On-load tap-changer in lieu of the off-circuit tap-changer as specified in Section 7.6.2. All other requirements in accordance with Section 7.6

Wheels

Standard configuration as specified in Section 7.2.13.

Nortech fibre optic monitoring system

Provision of direct monitoring 6 channel fibre optic monitoring system for transformers.



Mounting plate with anti vibration pads

An alternative to wheels as specified in Section 7.2.14

Neutral HV connection

Optional as specified in Sections 7.5.2, 7.5.4 and Appendix A.

Tests

Prices for the following tests:

• Routine tests • Sound level test: • Doble power factor test: • Temperature rise test: • Lightning impulse test: • Special Test • Transformer Inductance Test

Delivery costs



Appendix B Request for Tender Checklist Application

The following material is for guidance in the preparation of a Reguest For Tender for this type of equipment. This checklist itself is not intended to directly form part of any contract.

This section to be read in conjunction with the RFT Checklist in specification EP 00 00 00 15 SP, Common Requirements for Electric Power Equipment.

Information to be sought from the tenderer

• Tenders to complete and submit Technical Schedule at Appendix A • Tenders to complete and submit Integrated Support information as per Railcorp

Standard EP 00 00 00 12 SP Electrical Power systems – Integrated Support Requirements

Information to be supplied at time of order

Where this standard is used as the basis for procurement of rectifier transformers for a particular location, in addition to the general requirements in this standard the following information will need to be supplied related to the particular site:

ITEM DETAIL COMMENT Substation location

Substation Auxiliary Supplies

AC 1Ø Or AC 3Ø AC Voltage DC Voltage

……………… ………………

Number of rectifier transformers Power rating 2.68 MVA 4.28 MVA

5.35 MVA

Rated primary voltage. 33 kV 66 kV Primary connection HV Cable HV Bushing Number, size and type of secondary conductors/Phase. (12 Phases)

2.5 MW 5 x 240mm2 4 x 400mm2

4.0 MW 9 x 240mm2 6 x 400mm2

5.0 MW 12x240mm2 8 x 400mm2

Any site specific limitations on size or arrangement.

Headroom Available

Base/Footings prepared



Limitations due to access or transport.

Access road weight limit

Access times

Maximum road width (2.5 metres)

Maximum standard height above road. (4.3 metres)

Access road alongside operating railway.

Safe-working considerations

Transformer mounting

Wheels or Mounting plates with anti vibration pads

Neutral Bushing Required / not required

Neutral cable connection Required / not required

Tender documents to note that the LV bushing connection animal covers (see Section 7.5.3) are not required in the supply from the transformer supplier – these will be supplied by the installer to accommodate the number and arrangement of cables used.



Appendix C Requirements for Technical Aspects of Tender Evaluation

Evaluation of tenders

The Chief Engineer Electrical requires that persons evaluating the technical aspects of this tender have sufficient technical competence for the task.

Tender evaluation committees shall forward details of persons evaluating the technical aspects of the tender to the Chief Engineer Electrical for concurrence. This will normally be in the form of an email and is to include sufficient detail of the tender and the person to enable the Chief Engineer Electrical to satisfy themself of the merits of the evaluating person. A minimum of 4 weeks notice is required prior to the evaluation of the Tenders.

The Chief Engineer Electrical will advise only if the person is considered unsuitable for the technical evaluation.

Acceptance of product

A number of the specifications require acceptance of product at both the factory and at site. The purchaser is to advise the Chief Engineer Electrical the details of the person carrying out the acceptance testing for the concurrence of the Chief Engineer Electrical. A minimum of 4 weeks notice is required prior to the evaluation of the acceptance testing.

The Chief Engineer Electrical will advise only if the person is considered unsuitable for the acceptance testing.

The Chief Engineer Electrical reserves the right to nominate a representative to review and/or attend such acceptance.

Record Keeping

Where product is purchased against this specification, the Chief Engineer Electrical requires that relevant detail be provided so that it can be logged against this specification.

For RailCorp purchases, the tender evaluation committee shall advise the Chief Engineer Electrical the RailCorp registered file details containing the tender evaluation for future referencing. This is normally a TRIM reference.

Where this specification is utilised by parties external to RailCorp (Alliance parties, etc) then copies of all relevant technical information and evaluation shall be forwarded to the Chief Engineer Electrical for filing against the specification. In addition copies of selected commercial information pertaining to the ongoing support of the product as follows is also required.

• Warranty details • Spare parts and associated availability • Product support information.

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