Document no. 56008-10 Sag 10/4054 – ETS-03 v. 3

Document title
Document no.
Target group
HV, MV, LV and Signal Cables and Cable Routing
56008-10
Fabrications Contractors and Designer for Offshore substations.
Revision
Document status
Writer Reviewer Approver
Init Date Init Date Init
1
2
1st edition and revision
Deviations to Anholt platform design.
N/A
N//A
12.10.09
15.11.10
N/A
N/A
12.10.09 SGH
15.11.10 SGH
3 Approved xomo 18.09.12
SGH, POB,
TAN, XBOH,
POD
18.09.12 SGH
Minor alterations, type errors, rephrases' e.t.c where the meaning of the text is left unchanged are not shown .
Date
12.10.09
15.11.10
18.09.12
Document no. 56008-10 Sag 10/4054 – ETS-03 v. 3

1.
Scope
2.
References
2.1
Statutory Regulations
2.2
Codes and Standards
3.
Definitions
3.1
Definitions
4.
Technical Requirements
4.1
General
4.1.1
Requirements
4.1.2
Cable segregation
4.1.3
Cable ladders and trays
4.1.4
Cable installation
4.1.5
Cable pulling force and bending radius
4.1.6
Cable cleating and strapping
4.1.7
Cable splicing
4.1.8
Temporary cables
4.1.9
Cable gland selection
4.1.10
Termination
4.1.11
Spare conductors
4.1.12
Marking
4.2
MV cables
4.2.1
Specification
4.2.2
Selection
4.3
LV cables
4.3.1
Specification Power supply cable
4.3.2
Selection
4.4
Signal cables
4.4.1
Specification for category 5e cables
4.4.2
Specification for coax cables
4.4.3
Specification for optical fibre cables
4.4.4
Specification for twisted pair cables
4.4.5
Specification for non twisted pair cables
4.4.6
Selection
5.
Certificates / Data books
6.
Appendix
1
9
10
10
10
7
8
8
9
10
11
11
6
7
7
7
5
5
6
6
3
4
5
5
3
3
3
3
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1
1
1
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2
11
Document no. 56008-10 Sag 10/4054 – ETS-03 v. 3

This technical standard specifies the basic requirements for the High, Medium and
Low Voltage and signal cables to be used on an offshore located transformer platform for offshore wind farms established in the Danish offshore sector.
Further the installation, segregation and support of cables is described in general terms.
2.1
Statutory Regulations
 Direktiv 2006/95/EF Lavspændingsdirektivet.
 Stærkstrømsbekendtgørelsen, afsnit 6 Elektriske installationer.
 BEK nr. 27 af 10/01/2007 Bekendtgørelse om radio-og teleterminaludstyr og elektromagnetiske forhold
(EMC Direktiv 2004/108/EF).
2.2
Codes and Standards
 ANSI/TIA 568B
 EN 50167
 EN 50173
 IEC 11801
 IEC 60038
 IEC 60092
 IEC 60183
 IEC 60287
 IEC 60228
 IEC 60331
 IEC 60332
 IEC 60364
 IEC 60724
 IEC 60754
Communications cabling standard
Sectional specification for horizontal floor wiring cables with a common overall screen for use in digital communication
Information technology – Generic cabling systems
Information technology – Generic cabling for customer premises
IEC standard voltages
Electrical installations in ships
Guide to the selection of high-voltage cables
Electric cables – Calculating of the current rating
Conductors of insulated cables
Tests for electrical cables under fire conditions
Tests on electric and optical fibre cables under fire conditions
Low-voltage electrical installations
Short-circuit temperature limits of electric cables with rated voltages from of 1 kV (U m
=1,2 kV) and up to 3 kV
(U m
=3,6 kV)
Test on gasses evolved during combustion of electric cables
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 IEC 60793
 IEC 60794
 IEC 60840
 IEC 60885
 IEC 60949
 IEC 60986
 IEC 61034
 IEC 61034
 IEC 61443
 IEC 61892
 IEC/TR 62095
 DNV-OS-J201
3.1
Definitions
 Shall:
 Should:
 May:
 Can:
 Substation:
Optical fibres
Optical fibre cables
Power cables with extruded insulation and their accessories for rated voltages above 30 kV (U m
= 36 kV) up to 150 kV (U m
=170 kV) – Test methods and requirements
Electrical test methods for electrical cables
Calculation of thermally permissible short-circuit currents, taking into account non-adiabatic heating effects
Short-circuit temperature limits of electric cables with rated voltages from of 6 kV (U m
=7,2 kV) and up to 30 kV
(U m
=36 kV)
Measurement of smoke density of cables burning under
Measurement of smoke density of cables burning under defined conditions
Short-circuit temperature limits of electric cables with rated voltages above 30 kV (U m
=36 kV)
Mobile and fixed offshore units – Electrical installations
Electric cables – Calculation for current ratings – Finite element method
Offshore Substations for Wind farms.
Verbal form used to indicate requirements to be strictly followed in order to conform to the standard and from which no deviation is permitted, unless accepted by all parties.
Verbal form used to indicate that among several possibilities one is recommended as particularly suitable, without mentioning or excluding others, or that a certain course of action is preferred but not necessarily required.
Verbal form used to indicate a course of action permissible within the limits of the standard.
Verbal form used for statements of possibility and capability, whether material, physical or casual.
“Transformer Platform”
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4.1
General
4.1.1
Requirements
Cables shall comply with the relevant standards applicable for the particular use of the cable.
All cables used shall be minimum flame retardant (IEC 60332). Fire resistant cables shall be used for essential services such as fire detection and alarming and emergency lighting.
Generally all cables should have a tinned copper braid armouring and an outer sheath which is UV resistant.
4.1.2
Cable segregation
Signal cables shall be routed separate from HV, MV and LV cables. Minimum distance should be 600mm to HV and MV cables and 300mm to LV cables. Instrument cables and communication cables can generally be routed together.
Signal cables crossing at a right angel with LV cables is acceptable without further segregation.
High voltage cables shall in the full length be separated from medium voltage and low voltage cables by at least 300 mm unless mechanically separated by earthed metal partitions or pipes.
Medium voltage cables shall in the full length be separated from High voltage and low voltage cables by at least 300 mm unless mechanically separated by earthed metal partitions or pipes.
Considerations must be taken during installations of cables entering and leaving equipment like power transformers, crane etc. related to the requirements of segregation.
4.1.3
Cable ladders and trays
All cables should be routed on cable ladders, cable trays and/or J-tubes.
The routing must be divided into the following 4 systems:
- HV cables
- MV cables
- LV cables
- Signal/instrument cables
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Outdoor cable ladders and trays shall be Glass fibre Reinforced Plastic (GRP) for MV,
LV and signal/instrument cables. For HV cables the cable ladders and trays shall be
AISI-316 stainless steel.
All GRP materials shall be fire retardant and have a flame spread rating in accordance with ASTM E-84 class I or BS-476 part 7 class 0, I & II. The GRP material shall further contain an ultraviolet inhibitor, tested to BS-2782.
All connector plates and fasteners for GRP ladders and trays must be made of stainless steel AISI 316L.
Indoor cable ladders and trays may be Hot dip galvanised.(DS/ISO/EN 1461)
Conduits may be used for special mechanical protection of single field routed cables for shorter distances.
The cable ladders and trays shall not be filled so the height of their side rail is exceeded. Further the ladders and trays should not be filled beyond 85% of their total capacity.
Redundant cable systems shall as far as possible be routed separately.
MV cables should be routed and grouped depending of the chosen current carrying capacity estimation method, according to section 4.2
4.1.4
Cable installation
Access for maintenance and an orderly layout shall be ensured when cabling below raised floor is performed.
Once a cable has been cut, a protective cap/sealing shall be applied on the end, when being exposed to humid atmosphere.
All cable entries to equipment located outdoor and in deluge covered areas shall to the extent possible, be installed from below. Top entry is not allowed. Side entry shall be provided with additional protection against ingress of moisture.
Sufficient cable spare length shall be provided for equipment which needs future adjustments (floodlights, loudspeakers, TV cameras etc.) or where equipment has to be dismounted for maintenance and calibration without disconnecting the cable.
Single core cables for three-phase ac shall run in trefoil formation. The braided armour and screen shall be earthed in both ends.
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Single core cables shall not be installed separately through openings surrounded by magnetic materials. Non-magnetic stainless steel separation walls and stay plates shall be used in cable transits used for single core cables.
4.1.5
Cable pulling force and bending radius
The maximum pulling force and minimum permissible bending radius specified by supplier shall be adhered to.
4.1.6
Cable cleating and strapping
All cables shall be fixed properly to the cable support systems.
Plastic coated stainless steel straps shall be used for all cable runs outside and in non ventilated areas.
UV resistant nylon straps may be used for horizontal runs in indoor and ventilated locations.
The Plastic coated stainless steel straps shall be used for vertical runs and for horizontal runs in the vertical plane both indoor and outdoor. For strapping of fibre- optical and coaxial cables, supplier guidelines shall be adhered to.
The distance between cable straps shall not exceed:



600mm for horizontal runs
300mm for vertical runs and for horizontal runs in the vertical plane
Ten times the cable outer diameter from cable entry to the first strap
Single core HV and MV power cables for three-phase ac shall be fixed with trefoil cable cleats which shall be approved for the potential short circuit stress.
The distance between trefoil cleats shall be as specified by the cable manufacturer based on the calculated short circuit level. The distance shall be selected such that the cable will not be damaged by a possible short circuit. Normal distance is 300mm, and on every step on bends and risers.
4.1.7
Cable splicing
Cable splicing should be avoided.
If splicing seems unavoidable it shall be agreed with Energinet.dk for the installation in question.
4.1.8
Temporary cables
Temporary cables routed on permanent cable support systems shall be installed such that they will not obstruct permanent installations and are easy to remove.
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4.1.9
Cable gland selection
Cable glands, bushings, modular multi cable transits (MCT) or fittings for screwed conduits, shall be provided according to the way in which the cables enter the equipment or rooms. All entries shall maintain the degree of protection provided by the enclosure of the associated equipment or room. These shall apply to the whole range of cable dimensions specified by the manufacturer of the cable entries as suitable for use with those entries.
EMC-glands to be used where separate earth bar not are available.
Glands installed in non-metallic equipment shall be earthed separately.
Types, maximum numbers and positions of Cable glands and blanking element entries for mounting in electrical apparatus for installation in explosive gas atmospheres shall be specified in a document submitted by the manufacturer.
Shrouds and similar shall not be used on cable glands.
4.1.10
Termination
Cable conductors shall be terminated by use of compression lugs dependent upon the type of termination.
Support for cleating of cables when entering the panels should be provided.
In switchboards and distribution board's adequate space shall be provided for the use of a clip-on ampere meter without causing undue stress on the cable conductors or connections.
Armour and screen shall be earthed via EMC-glands (360 0 )
Only one conductor is allowed in each terminal of a terminal block/row for external connections. This is not related to terminals as integrated part of internal components (e.g. relays and contactors) of the equipment. Two conductors may in certain cases be used in one approved type ferrule connected to one terminal.
4.1.11
Spare conductors
Spare conductors in instrument and telecom cables shall be terminated at the cabinet end and left floating at the field end.
In cabinets all spare conductors shall be marked with terminal number and connected to terminals linked together by solid terminal links, which shall be connected to the relevant earth bar.
Spare cores in instrument and telecom cables shall be connected to earth in supply end only.
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If there are no spare terminals left in the cabinet, all spare conductors shall be covered with yellow/green sleeves and marked with relevant cable number and connected directly to the relevant earth bar.
4.1.12
Marking
Numbering of cables shall be in accordance to the relevant document standard for the platform.
Each cable shall be marked with indelible and non-corrosive cable markers indicating the cable number. The cable markers shall be clearly visible after cleating and strapping. Outdoors, in exposed- and deluge covered areas the cable markers should be made of stainless steel.
Each cable shall have a cable marker located in both ends.
4.2
MV cables
The designation “Medium Voltage cables (MV cables)” applies to cables for fixed installations in all installations, whether permanent, temporary, transportable or hand-held, to ac three-phase systems having a nominal voltage above 1 kV and not exceeding 100 kV.
The characteristics of the Medium Voltage range is specified according to IEC
60038, IEC standard voltages.
4.2.1
Specification
Cables constructed in accordance with IEC 60092-350, IEC 60092-353, IEC
60092-354 and IEC 60092-376 are recommended for use as MV cables on fixed offshore units.
4.2.2
Selection
The selection of the standard MV cable characteristics and type is based on the actual nominal system voltage and the demanded current carrying capacity.
The choice of standard cables of appropriate voltage designations for particular systems depends upon the system voltage and the system earthing arrangements.
Guidance for the selection of the cable conductor size, cable insulation level and cable construction is given according to IEC 60183.
The lightning over-voltage of the cable must comply with the defined lightning protection zones and the effects of the installed lightning protection provisions.
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The choice of standard cables of appropriate cross-sectional area of conductors and current carrying capacity should be estimated according to one of the following methods:
- As described according to IEC 60287
- By calculation using a recognized method provided that the method is stated
- According to IEC 61892-4, Annex A
- According to IEC 61892-4, Annex B
The estimated current carrying capacity should be modified with the adequate correction factors for different ambient air temperatures, according to IEC 61892-4, clause 4.3.4.
The selected cables and their insulated conductors shall be capable of withstanding the mechanical and thermal effects of the maximum short circuit current which can flow in any part of the circuit in which they are installed, taking into consideration not only the time/current characteristics of the circuit protective device, but also the peak value of the prospective short circuit current during the first half cycle.
The cable short-circuit current withstand capability should be evaluated according to information given in IEC 60724, IEC 60986 and IEC 60949.
New and modified cable installations should be electrically tested as specified according to IEC 60885.
4.3
LV cables
The following specified LV cables are intended for use in power supply to installations such as lighting, socket outlets, heaters, panels etc. Same cables shall be used whether AC or DC power.
All LV cables shall be fire resistant and in accordance with IEC 60331.
4.3.1
Specification Power supply cable
With the exception of single core cables or if the consumer is earthed locally, all power supply cables from switch gear to consumers shall have an integral dedicated green/yellow earth wire.
Cable design for platform services should be:
Conductor: Stranded bare copper
Insulation:
Inner covering:
Cross linked polyethylene (XLPE)
Halogen free filler (i.e polyolefin)
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Armouring:
Outer sheath:
Copper braid (Tinned)
Polyolefin
4.3.2
Selection
LV cable types shall be selected to meet the requirements specified according to
IEC 60092-352, Clause 3.1.
All cables or insulated wiring shall meet the requirements for flame spread as specified according to IEC 60092-352, Clause 3.14.
The cable voltage rating shall comply with the requirements specified according to
IEC 60092-352, Clause 3.2.
Cable cross-sectional areas and current carrying capacity of conductors shall comply with the requirements specified according to IEC 60092-352, Clause 3.3.
Cable current ratings for continuous service shall, according to IEC 60092-352,
Clause 3.3.3, be selected from Annex B, Tabulated Current Carrying Capacities –
General Installations.
The conductor current carrying capacity of parallel connections of single core cables or multi core cables shall comply with the requirements specified according to IEC
60092-352, Clause 3.6.
Cables and their insulated conductors shall be capable of withstanding the mechanical and thermal effects of the maximum short circuit current which can flow in any part of the circuit in which they are installed, taking into consideration not only the time/current characteristics of the circuit protective device, but also the peak value of the prospective short circuit current during the first half cycle. Further information is given in IEC 60949 and IEC 60724.
Cables for essential/emergency power supply shall fulfil the requirements of IEC
60331.
4.4
Signal cables
The following systems shall have their own dedicated cables:



Digital communication (category 5e, optical fibre and coax)
Fire detection and alarming (Twisted pairs)
Equipment monitoring and alarm (Twisted pairs or non twisted pairs)
The detailed specifications in the following sections should be regarded as recommendations. Other cable specifications may be used provided accepted by
Energinet.dk
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4.4.1
Specification for category 5e cables
Category 5e communication cables should be standard twisted 4 pair 100 MHz manufactured in accordance with ANSI/TIA 568B.
Conductor:
Conductor insulation:
Bare copper (D. 0.52mm)
Polyethylene, PE
Collective screen:
Outer sheath:
Aluminium/polyester tape with tinned copper drain wire and tinned copper braid
Polyolefin
4.4.2
Specification for coax cables
Coax cables should be standard 50 ohms.
Conductor:
Dielectric:
Bare copper-stranded 7 x 0.75mm
Solid polyethylene Ø7.24mm
Inner screening:
Inner jacket:
Armouring:
Outer Sheath:
Bare/tinned copper braid
Halogen free compound (outer sheath if used inside)
Tinned copper braid (applicable for outdoor use)
Halogen free compound (applicable for outdoor use)
4.4.3
Specification for optical fibre cables
Optical fibre cables should be carefully chosen for the particular use.
Optical fiber:
Clading diameter:
Single mode type G.652D
Multi mode glass core 62.5 µm
125 µm
Armouring:
Outer Sheath:
Double-sided LSZH corrugated steel tape
LSZH with parallel double steel wire as strength member.
4.4.4
Specification for twisted pair cables
Twisted pair cables should normally be with common screen unless the particular installation require individual screen.
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Conductor:
Insulation:
Stranded bare copper (Ø 0.75mm
2 ) Twisted in pairs
Cross linked polyethylene, XLPE
Collective screen:
Armouring:
Outer sheath:
Aluminium/polyester tape with tinned copper drain wire and tinned copper braid
Tinned copper braid
Polyolefin
4.4.5
Specification for non twisted pair cables
Non twisted cables should normally be with common screen, and without an integral dedicated green/yellow earth wire.
Conductor: Stranded bare copper
Insulation:
Inner covering:
Armouring:
Outer sheath:
Cross linked polyethylene (XLPE)
Halogen free filler (i.e. polyolefin)
Copper braid (Tinned)
Polyolefin
4.4.6
Selection
The Category 5e cable should be used for all communication which is not fibre based.
This cable should be for indoor use only, if used outdoor it shall be protected from the sun and from mechanical damage.
The coax cable should be used for the transmission of signals from control panel to
VDU, and for radio transmission via externally fixed antennas.
NA.
NA.
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