Kontaktledning/Kiosk for autotransformatorer

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, 5, and 6 MVA autotransformers. The original title of the swedish document is BVS 1543.14515 - Kraftförsörjningsanläggningar. Transformatorbyggnad för autotransformator med märkeffekt 3, 5 och 6 MVA. Transformer housing for autotransformer with a rated output of 3, 5 and 6 MVA, dated 25. mars 2019.

The document is a joint publication by Trafikverket (the Swedish Transport Administration) and Bane NOR (the Norwegian National Rail Administration).

Proposals for alteration regarding this specification shall be put to Høyspenning, Elkraft, Teknisk, Drift og teknologi, Bane NOR.

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 clients, tenderers, suppliers, designers, contractors, and inspectors.

Trafikverket and Bane NOR is called the purchaser in this document.

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

1. 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.
2. Both the superstructure and the foundation shall be type-certified by Trafikverket.
3. Both the superstructure and the foundation shall withstand temperatures between -50 to +40 °C.
4. The total height of the transformer housing above ground level shall not exceed 3600 mm.
5. The size of the transformer do not exceed following measurement; length (L) 2100 x width (W): 2400 x height (H) 3800 mm.
6. The exterior design of the transformer housing may, in some cases, be subject to the requirements of the Swedish or Norwegian building code.
7. The detailed design of the transformer housing is to be finalized in the course of technical construction reviews.
8. The transformer housing shall fit an already type-certified 3, 5 and 6 MVA autotransformer.
9. With the foundation, two oakboards shall be delivered and each one of the boards shall not be thicker than 40 mm.
10. The two oakboards shall be placed between the transformer and the a foundation.

6 Superstructure

1. The superstructure shall be erected in corrosion-proof material with a lifespan of at least 40 years.
2. The materials of the superstructure shall be of a solid material that prevents unauthorized access in the transformer housing.
3. The superstructures shall at least be metal coated with Zinc (Z) with a minimum total coating mass of 275 g/m² on both surfaces (Z275) or similiar.
4. For internal and exterior painting, an EN ISO-12944-compliant rustproofing system shall be used.
5. For internal and exterior painting, corrosiveness class C4 and durability rating High shall be applied.
6. The color code for the exterior painting of the walls shall be Green, NCS 6010-G50Y and the roof shall be Black, NCS 9000N or equal for Trafikverket superstructures.(Trafikverket onely)
7. The color code for the exterior painting shall be grey, RAL 7035.(BaneNor onely)
8. The color code of the transformer housing may, in some cases, be subject to the requirements of the Swedish building code.(Trafikverket onely)
9. The color code of the transformer housing may, in some cases, be subject to the requirements of the Norwegian building code.(BaneNor onely)
10. The surface on the roof and walls shall not be light reflective.
11. Exterior surface of walls shall be protected with environmental friendly “anti-graffiti” painting.
12. There shall be sufficient space inside (at both short sides and the side toward the radiator/expansion vessel) the superstructure for inspection and maintenance purposes.
13. The superstructure shall be fitted with steps, leading down to interior floor level.
14. A document holder, easily accessible from outside via a door, shall be located inside the superstructure.(Trafikverket onely)
15. The door handle and padlock shall be recessed, with a covering lid.
16. There shall be a set of metal latticework steps below the door on the exterior.
17. A lockable door shall be located at gable (short side) of the superstructure.
18. The door shall be fitted with a doorstop.
19. The doorblade shall have a height of minimum 2 m and a width of 0,8 m according to BBR 5:341 in document “utrymmningsvägar” edition 1, 2006.
20. The door shall turn outwards.
21. The interior walls shall be designed so that any spray oil from the transformer runs down into the foundation.
22. The superstructure shall have an integrated and unlockable cable duct that is recessed into the wall.
23. The cable duct shall be designed to fit four 36 kV 1 x 500 mm² cables.
24. The cable duct shall be located on the short side (gable) that is opposite side of the door and in line with the position of the autotransformers bushings.
25. The lower part of the cable protector shall be expandable (which will be partially buried in the ground) and made of 4-mm stainless steel sheets.
26. The upper part of the cable protector is to have the same exterior coating as the superstructure.
27. Fixed nuts for attaching the cable protector shall be located in the wall (not sheet-metal screws).
28. The necessary apertures for cables and lines shall be present in the superstructure.
29. The roof of the superstructure shall be easily removable.
30. It should be possible to lift the roof using lifting eyes.
31. The roof shall be designed so that water does not accumulate in depressions.
32. The roof shall be constructed with overhang and not exceeding total length of 3000 mm.
33. The superstructure shall be prepared for metal gutters and downpipes.
34. Metal gutters and downpipes shall be delivered seperatly, not assembled on the superstructure during transportation.
35. The superstructure shall be designed so that it is difficult to climb on.
36. The superstructure’s ventilation system shall be constructed in such a way that the stated temperature limits in IEC 60076-1 section 4.2 for the transformer are not exceeded.
37. Ventilation grilles shall be designed so that rain and snow cannot penetrate the superstructure under normal wheather conditions.
38. Ventilation grilles shall be designed so that spray oil from the transformer cannot escape from the superstructure meaning minimum IP 23 D according to IEC 60529.
39. The ventilation shall be dimensioned to manage a heat generation that equals to 1,7 x P_b (load losses of the 6 MVA autotransformer. The data for load losses is received from Trafikverket), without exceeding the transformers temperature limits.
40. The necessary signage as required by law shall be installed on the door and the superstructure.
41. Position signs shall be installed on the superstructure.
42. Text for these signs can be obtained from the customer.
43. The superstructure shall bear the manufacturer’s type and serial numbers.

7 Foundation

1. The foundation shall be constructed in accordance with L4 (50 years) EN 1990:2002 (Eurocode - Basis of structural design)
2. The foundation shall be constructed in accordance with Safety Class GK1 standard.
3. The foundation shall be constructed in accordance with Exposure Class XC4/XF4 standard.
4. The foundation shall be constructed to withstand a transformer with a total weight 20.000 kg.
5. The foundation shall be designed to support at least the full volume of transformer oil, which equals to approximately 3800 litres.
6. The foundation shall be able to withstand burning transformer oil.
7. The foundation (sump) shall be watertight, impermeable to oil, and constructed from C35/45 reinforced concrete.
8. The fluid shall have possibility to move between the different cells of the foundation.
9. The foundation is to be produced in one piece without any joints.
10. The foundation shall be tested with method A, VCT ≤0,4 according to SS 137244.
11. The foundation shall 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.
12. The foundation shall be frost-resistant.
13. The reinforcement structure (armouring) is to be welded in accordance with BBK, section 8.6.2.1.
14. The foundation shall be constructed in such a way that oil that has flowed into the sump cannot burn.
15. The foundation shall be equipped with an extinguishing grid.
16. The extinguishing grid shall be made for easy access to the basement of the foundation without removing the transformer.
17. The extinguishing grid shall be galvanized metal and connected to electrical grounding system.
18. The conductor or plates that connects the gridplates shall be tinned copper and have a cross section of at least 50 mm².
19. The foundation shall bear the manufacturer’s type and serial numbers.
20. The type description is to be determined in consultation with the customer.
21. A geotechnical construction specification, including requirements regarding foundation laying, shall be supplied.
22. The foundation shall be equipped with four appropriate lifting anchors.
23. The foundation armouring shall form an electrical grounding system.
24. The reinforcement structure is to be grounded in accordance with EN 50122-1.
25. The electrical grounding system shall be equipped with electrical terminals connected to the ground distribution block on one of the foundation walls.
26. The location of the grounding components shall be according to drawing 115 863 (Trafikverket).
27. Four M 12 bolts shall be recessed in the wall (opposite side of the entrance door) inside the foundation for assembly of two groundbars , Trafikverket article 0420060.
28. There shall be atleast 50 mm between the groundbars.
29. The walls of foundation shall be equipped with hot-dip galvanized clamping band intended for calmping groundcable.
30. The clampingband shall be installed according to drawing 115 863 (Trafikverket).
31. The clamping band shall be at least of size 25 x 3 mm.

8 Earthing

1. The foundation armouring shall form an electrical grounding system.
2. The reinforcement structure is to be grounded in accordance with EN 50122-1.
3. The electrical grounding system shall be equipped with electrical terminals connected to the ground distribution block on one of the foundation walls.
4. The location of the grounding components shall be according to drawing 115 863.
5. Four M 12 bolts shall be recessed in the wall (opposite side of the entrance door) inside the foundation for assembly of two groundbars, Trafikverket article 0420060.
6. There shall be atleast 50 mm between the groundbars.

9 Documentation

1. All documentation must be supplied in electronic format.
2. Three sets of hard copies in binders must be supplied.(Trafikverket only)
3. The documentation must comprise:

a) Layout drawings of the finished transformer housing, including the transformer

b) Calculations for the foundation

c) Calculations for superstructure air intakes

d) Construction specification for the superstructure and foundation

e) Manufacturer’s drawings of the superstructure and foundation

f) Instructions for lifting the transformer into and out of the housing

g) Wiring diagram showing layout of wires and cables inside the transformer housing (Trafikverket has its own specification for this topic)

h) All quality assurance documentation for each transformer housing

i) Instructions for care and maintenance of the transformer housing

j) Instructions for installation and dismantling of the transformer housing

k) Instructions for disposal (scrapping) of the transformer housing

10 Construction audits, manufacturing inspections, and type certification

10.1 Scope

Before a transformer housing can be type-certified, it shall undergo construction audits, manufacturing inspections, and verification by means of heat run testing (temperature rise test) with autotransformers.

a. Construction audit prior to purchasing.

b. Construction audit after purchasing.

c. 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.

d. Heat run testing with a transformer inside the housing, shall be performed by an accredited laboratory, at the transformer manufacturer.

e. Type certification of the transformer housing (superstructure and foundation) and autotransformer can proceed once the heat run testing report confirms that the test results were satisfactory.

10.2 Construction audit prior to purchasing

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

10.3 Construction audit after purchasing

1. Following purchasing and before the transformer housing (superstructure and foundation) enters production, a detailed construction audit shall be performed.
2. The supplier shall present documentation of this audit to the customer in Swedish or Norwegian.
3. The audit documentation shall cover the items listed in sections Superstructure, foundation and procedures.

10.3.1 Superstructure

• Choice of materials
• Construction drawings
• Fastening of superstructure to foundation
• Ventilation calculations (that shows that the ventilation is capable to transport 1,7 x the load losses).
• Ventilation grilles
• Painting/coating system
• Production process
• Transport
• Trial installation of first production superstructure on foundation
• Installation

10.3.2 Foundation

Choice of materials

• Choice of materials
• Estinguishing grid, type and manufacture
• Construction drawings
• Construction calculations
• Production process
• Engineering of foundation laying
• Transport
• Trial installation of superstructure on first production foundation
• Installation

10.3.3 Procedures

The supplier shall draw up procedures for the following:

1. Manufacturing inspection by the design office in connection with delivery of the first transformer housing (superstructure and foundation)
2. Version management of drawings
3. Manufacturing inspection schedule for superstructure and foundation
4. Quality assurance of assembly at the delivery site
5. On-site installation
6. Construction inspection of the transformer housing.

10.4 Manufacturing inspections

1. During serial production of transformer housings (superstructure and foundation), the customer’s representatives shall be entitled to visit the factory whenever they wish.
2. 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.

10.5 Heat run testing of transformer housing with the intended autotransformer

1. Heat run testing (temperature rise test) is to be conducted in accordance with TDOK 2014:0680, using the intended transformer housing.
2. The foundation may be replaced with a mock-up.

10.6 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 shall be reported to and approved by Trafikverket or Bane NOR on an ongoing basis

11 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

IEC 60529 Degrees of protection provided by enclosures (IP Code)

IEC 60076-1 Power Transformers – Part 1; General

Source for this document: This document is an copy (2. april 2019) of the Trafikverket specification TDOK 2014:0681, which can be found on the internet page: Trafikverket: Sök styrande och stödjande dokument.