Kontaktledning/Kiosk for autotransformatorer

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1 Purpose

This standard (in Trafikverket caled BVS) or technical specification (in Jernbaneverket), has been drawn up in order to standardize the production of transformer housings for 3 and 5 MVA autotransformers.

2 Scope

This standard, or technical specification, sets out the Trafikverket and the Jernbaneverket requirements regarding the design of transformer housings, comprising superstructure and foundations, for autotransformers supplying traction current.

The document shall be applied in connection with the Trafikverket public procurements. The document is intended for tenderers.

3 Definitions and abbreviations

3.1 Definitions

This standard, or technical specification, contains no terms or concepts that need to be defined.

3.2 Abbreviations

AT – Autotransformer

4 Responsibility

Not relevant.

5 General

  • A transformer housing for an autotransformer supplying traction current comprises a superstructure and a foundation. Both the superstructure and the foundation must be type-certified by Trafikverket.
  • The total height of the transformer housing above ground level must not exceed 3600 mm. The transformer housing may be placed below ground level.
  • The exterior design of the transformer housing may, in some cases, be subject to the requirements of the Swedish or Norwegian building code.
  • The detailed design of the transformer housing is to be finalized in the course of technical construction reviews.
  • The transformer housing must also fit an already type-certified Type II autotransformer.

6 Superstructure

  • The superstructure must be erected in corrosion-proof material with a lifespan of at least 30 years.
  • The materials of the superstructure shall be of a solid material that prevents unauthorized access in the transformer housing.
  • For exterior painting, an ISO-12944-compliant rustproofing system must be used. For exterior painting, corrosiveness class C3 and durability rating High apply in all parts of Sweden except the west coast. For the west coast of Sweden and all of Norway, corrosiveness class C4 and durability rating High apply.
  • The colour code for the exterior painting must be agreed upon for each order.
  • Exterior surface of walls shall be protected with "anti-graffiti" painting.
  • There must be sufficient space inside the superstructure for inspection and maintenance purposes.
  • The superstructure must be fitted with steps and a handrail inside the door, leading down to interior floor level.
  • A document holder, easily accessible from outside via a door, must be located inside the superstructure.
  • The superstructure must be fitted with a lockable door. The door handle and padlock must be recessed, with a covering lid.
  • There must be a set of metal latticework steps below the door on the exterior.
  • The door must be fitted with a doorstop.
  • The door must have a height of minimum 2000 mm.
  • The door must turn outwards.
  • The interior walls must be designed so that any spray oil from the transformer runs down into the foundation.
  • The superstructure must be fitted with a removable vertical cable protector. The lower part of the cable protector, which will be partially buried in the ground, is to be made of 4 mm stainless steel sheet. The upper part of the cable protector is to have the same exterior coating as the superstructure. Fixed nuts for attaching the cable protector must be located in the wall (not sheet-metal screws).
  • The necessary apertures for cables and lines must be present in the superstructure.
  • The roof of the superstructure must be easily removable. It should be possible to lift the roof using lifting eyes.
  • The roof must be designed so that water does not accumulate in depressions.
  • The roof must be constructed with a 200 mm overhang.
  • A snow guard must be fitted to the roof above the door.
  • The superstructure must be fitted with metal gutters and downpipes.
  • The superstructure must be designed so that it is difficult to climb on.
  • The superstructure’s ventilation system must be constructed in such a way that the stated temperature limits for the transformer are not exceeded.
  • Ventilation grilles must be designed so that rain and snow cannot penetrate the superstructure.
  • Ventilation grilles must be designed so that spray oil from the transformer cannot escape from the superstructure.
  • The necessary signage as required by law must be installed on the door and the superstructure.
  • Position signs must be installed on the superstructure. Text for these signs can be obtained from the customer.
  • The superstructure must bear the manufacturer’s type and serial numbers. The type description is to be determined in consultation with the customer.

7 Foundation

  • The foundation must be constructed to Lifespan Class L1 standard (50 years).
  • The foundation must be constructed to Safety Class GK1 standard.
  • The foundation must be constructed to Exposure Class XC4/XF4 standard.
  • The foundation must be designed to support the full volume of transformer oil.
  • The foundation (sump) must be watertight, impermeable to oil, and constructed from C35/45 reinforced concrete. The foundation is to be poured in one piece.
  • The foundation must be designed to withstand an overload on the surrounding ground of 20 kN/m2 or wheel pressure of 40 kN, equivalent to that of a truck or tractor.
  • The foundation must be frost-resistant.
  • The foundation must be finished above ground.
  • The foundation must be able to withstand burning transformer oil. The foundation must be constructed in such a way that oil that has flowed into the sump cannot burn.
  • Trafikverket requirement: The stone filter must be clean with no “gravel” residue. The stone filter must be placed on a galvanized metal grating with feet resting on the base of the foundation. The grating must come apart so that it is possible to access the base of the foundation.
  • Bane NOR requirement: Design of filter over the oil sump is to be decided by the supplier.
  • The foundation must be equipped with a sump pump with a lid. The base of the foundation must slope away to the sump pump.
  • The foundation reinforcement must form an electrical grounding system. The reinforcement structure is to be grounded in accordance with SS-EN 50122-1. The reinforcement structure is to be welded in accordance with BBK, section 8.6.2.1.
  • The electrical grounding system must be equipped with electrical connections connected to the ground distribution block on one of the foundation walls.
  • On the foundation inside the superstructure there must be a ground distribution block made of copper to provide protective grounding of the superstructure, foundation reinforcement, transformer, cable terminals, etc.
  • The foundation must bear the manufacturer’s type and serial numbers. The type description is to be determined in consultation with the customer.
  • A geotechnical construction specification, including requirements regarding foundation laying, must be supplied.
  • The foundation must be equipped with appropriate lifting points for lifting the foundation on site.

8 Documentation

  • All documentation must be supplied in electronic format.
  • Three sets of hard copies in binders must be supplied.
  • The documentation must comprise:

– Layout drawings of the finished transformer housing, including the transformer

– Calculations for the foundation

– Calculations for superstructure air intakes

– Construction specification for the superstructure and foundation

– Manufacturer’s drawings of the superstructure and foundation

– Instructions for lifting the transformer into and out of the housing

– Wiring diagram showing layout of wires and cables inside the transformer housing

– All quality assurance documentation for each transformer housing

– Instructions for care and maintenance of the transformer housing

– Instructions for installation and dismantling of the transformer housing

– Instructions for disposal (scrapping) of the transformer housing

9 Construction audits, manufacturing inspections, and type certification

9.1 Scope

Before a transformer housing can be type-certified, it must undergo construction audits, manufacturing inspections, and verification by means of heat testing with autotransformers.

  1. Construction audit prior to purchasing.
  2. Construction audit after purchasing.
  3. Manufacturing inspection of the first transformer housing (superstructure and foundation) and trial installation of the complete transformer housing. Once serial production starts, manufacturing inspections will take place continuously.
  4. Heat testing with a transformer inside the housing, performed by an accredited laboratory, transformer manufacturer, or similar organization.
  5. Type certification of the transformer housing (superstructure and foundation) and autotransformer can proceed once the heat-testing report confirms that the test results were satisfactory.

9.2 Construction audit prior to purchasing

  • In their bids, bidders must explain the basic data, the construction and dimensioning of the transformer housing, and the foundation requirements.
  • In their bids, bidders must account for any deviation from the requirements specified in the invitation to tender.

9.3 Construction audit after purchasing

  • Following purchasing and before the transformer housing (superstructure and foundation) enters production, a detailed construction audit must be performed. The supplier must present documentation of this audit to the customer in Swedish or Norwegian. The audit documentation must cover the items listed in sections 9.3.1 to 9.3.3.

9.3.1 Superstructure

  • Choice of materials
  • Construction drawings
  • Fastening of superstructure to foundation
  • Ventilation calculations
  • Ventilation grilles
  • Painting/coating system
  • Production process
  • Transport
  • Trial installation of first production superstructure on foundation
  • Installation

9.3.2 Foundation

Choice of materials

  • Construction drawings
  • Construction calculations
  • Production process
  • Engineering of foundation laying
  • Transport
  • Trial installation of superstructure on first production foundation
  • Installation

9.3.3 Procedures

The supplier must draw up procedures for the following:

– Manufacturing inspection by the design office in connection with delivery of the first transformer housing (superstructure and foundation)

– Version management of drawings

– Manufacturing inspection schedule for superstructure and foundation

– Quality assurance of assembly at the delivery site

– On-site installation

– Construction inspection of the transformer housing and transformer

9.4 Manufacturing inspections

  • During serial production of transformer housings (superstructure and foundation), the customer’s representatives shall be entitled to visit the factory whenever they wish.
  • On all visits to the factory, the customer’s representatives shall be entitled to take photographs of the transformer housings (superstructure and foundation) in production.

9.5 Heat testing of transformer housing with the intended autotransformer

Heat testing is to be conducted in accordance with TDOK 2014:0680 (former BVS 1543.14513), using the intended transformer housing. The foundation may be replaced with a mock-up.

9.6 Type certification of transformer housing

  • Type certification of the transformer housing (superstructure and foundation) and autotransformer can proceed once the heat-testing report confirms that the test results were satisfactory.
  • Any changes to the construction of or production procedures for a type-certified design must be reported to and approved by Trafikverket or Jernbaneverket on an ongoing basis.

10 Aids and references

10.1 Aids

Not relevant

10.2 References

This standard, or technical specification, refers to the following documents (if any of the EN, IEC, or ISO standards exist as Swedish and/or Norwegian standards, those will apply):

BBK Regulations on concrete structures (manual published by Boverket, the Swedish National Board of Housing, Building and Planning)

TDOK 2014:0680 (former BVS 1543.14513) Power supply installations – Autotransformers with a rated output of 3 and 5 MVA

EN 50122-1 Railway applications – Fixed installations – Part 1: Protective measures – Electrical safety and grounding


Source for this document: This document is an copy (14. July 2016) of the Trafikverket specification TDOK 2014:0681, which can be found on the internet page: Trafikverket: Sök styrande och stödjande dokument.

11 Change log