HTS Triax™ Energy Cable Systems

HTS Triax™ Energy Cable SystemsHTS Cables and Accessories

ANew Way To Energize

2

HTS Triax™ Energy Cable Systemsworld’s leading companies in the design,

manufacture and marketing of low, medium

and high-voltage cables and accessories. In

addition, with its workforce of 3000 employ-

ees this European high-tech corporation has

been making history in energy technology for

more than 130 years now. No wonder then

that nkt cables has also led the market in

researching and producing superconductive

cables from the very beginning. As early as

2001 the fi rst superconductive cable was

put into operation in a public power supply

network in Copenhagen. At the time a total of

50,000 households and companies benefi ted.

In future it will be millions.

High-temperature superconductor tech-

nology (HTS) is the key technology for

tomorrow’s electricity market. Compared

with copper conductors, HTS ceramic cables

have a number of signifi cant advantages. For

example they can conduct electric current

without resistance at app. 200°C below

zero. Transmission capacity is fi ve times

higher than that of conduc-tors made of

copper, while current loss is reduced to one

tenth. The development of HTS cables is

in-separably linked to the name nkt cables.

However, nkt cables is not just one of the

Property/Um/kV NT NE LV 10 15 36 72.5 150

PE-insulated, single phase X X D D

Coaxial, single phase X X D D D

Triax, three phase X X X X D D

Specialty conductors X (X) D D

NT: No Thermal Load, NE: No EMF, LV: Low Voltage specialty conductors, X: available, D: under development

Product Scope

HTS cables can be confi gured in several ways using the same materials and production processes. The most effi cient and high-performing

confi guration for the medium-voltage (MV) up to 72 kV is the HTS Triax™ design. nkt cables also has experience in coaxial single-phase

cables which are suitable for higher voltages. The HTS cable conductors can also be supplied with a conventional warm PE insulation.

nkt cables continually develops the voltage rating and the performance within the product scope described in the following table. nkt cables

offers cable conductors made from the 1st generation Bi2Sr2Ca2Cu3OX superconductors, while also working on integrating the new 2nd gene-

ration superconductors based on Y(RE)Ba2Cu3OX materials into these cable designs.“

Ultera® – helping to create the breakthrough

for HTS technologyThe potential of HTS technology is immense.

It is not just that energy suppliers no longer

lose unnecessary energy during transmission

across their extensive networks. Motors, ge-

nerators and transformers with HTS conduc-

tors are also much smaller, and achieve the

same output at much lower energy consump-

tion. For business the use of HTS technology

will mean long-term savings worth billions.

For people it is the future purely and simply.

In order to assist the HTS technology to

achieve its commercial break-through and

transform it as quickly as possible into

effective long-term solutions, nkt cables

and America’s biggest cable manufacturer

Southwire Company established the Ultera®

joint venture in 2002. Just like nkt cables,

Southwire is also an innovator and pioneer in

the fi eld of superconductor technology.

If the actual length of the cooperation

between the two companies is taken into

account, Ultera® now has ten years of practi-

cal experience in the daily provision of HTS

cables for energy supply in Europe and North

America. Together they represent the three

most successful installations worldwide with

HTS cables, thus opening the door wide to a

new way to energize.

®

HTS Cables with BSCCO tapes, copper stabiliser, Cryofl ex® dielectric, semifl exible cryostat

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Codes

HT: HTS triaxial cable design

B: BSCCO-type HTS conductor laminated

with a metal sheath

C: Added copper stabiliser

for over-current protection

BB CC CRCR SS WMWM 2Y2Y

Construction Code

Type HT-BC-CRS(WM)2Y 7.6/13.2 kV

Dimensions/Ampacity, 3x kA 1.25 2.00 2.5 3.0 3.4

Cable core

Conductor, BSCCO laminated, hollow ID mm 25 29 35 �1 �1

Copper stabiliser, cross section mm2 �0 �0 55 60 60

Cryofl ex® insulation mm 2.1 2.1 2.1 2.1 2.1

Screen, copper tape, cross section mm2 80 80 110 120 120

Outer cable core diameter mm �5 �9 62 68 68

Weight, HTS cable core, 3 phases kg/m 3.5 �.8 5.5 6.5 7

Permissible pulling force kN 10 15 20 20 20

Bending radius during laying/at terminations (min) m 3/1.5 3/1.5 3/1.5 3/1.5 3/1.5

Thermal insulation

Semi-right corrugated duct, ID/OD mm 60/110 60/110 8�/1�3 8�/1�3 8�/1�3

PE outer sheath thickness mm 2 2 3 3 3

Total OD 11� 11� 150 150 150

Termination OD mm 12� 12� 160 160 160



Heat leak, duct section W/m 1.2 1.2 1.5 1.5 1.5

Heat leak, joints W/ea. 10 10 15 15 15

Electrical data

Conductor DC resistance at Pnom µOhm/m <10 <10 <10 <10 <10

Conductor AC loss at Pnom *(Toperation 67 K to 79 K) W/m/ph 0.2-0.3 0.3-0.6 0.3-0.9 0.�-1.2 0.5-1.5

AC loss power factor, n P=k*ln 3 3 3 3 3

Capacitance, eqv. phase-to-ground µF/km 3.3 3.7 �.6 5.2 5.2

Inductance, eqv. single phase mH/km 0.026 0.02� 0.019 0.017 0.017

Power rating (continuous load) at 13,2 kV

1 circuit/2 circuits MVA 29/57 �6/91 57/11� 69/137 78/155

Construction code: HT-BC-CRS(WM)2Y

Construction code with

rigid thermal insulation: HT-BC-CRS(RL)2Y

Construction code with YBCO-type

HTS conductor: HT-YC-CRS(WM)2Y

CR: Cryofl ex® electrical insulation

S: Copper wire or tape screen

(WM): Corrugated “wellmantel” semifl exible

thermal insulation

2Y: polyethylene outer sheath

HT

*Conductor AC loss at Pnom depends on operation temperature, 67-79 K

�


Cable core



Cryoflex® insulation mm 3.� 3.� 3.� 3.� 3.�


Outer cable core diameter mm 57 61 67 73 73

Weight, HTS cable core, 3 phases kg/m � 5.2 6 7 7.5



Thermal insulation

Semi-rigid corrugated duct, ID/OD mm 8�/1�3 8�/1�3 8�/1�3 98/163 98/163


Total OD 150 150 150 170 170

Termination OD mm 160 160 160 180 180


Bending radius during laying/at terminations (min) m 3/1.5 3/1.5 3/1.5 �/2 �/2

Heat leak, duct section W/m 1.5 1.5 1.5 1.7 1.7


Electrical data


Conductor AC loss at Pnom*(Toperation 67 K to 79 K) W/m/ph 0.2-0.3 0.3-0.6 0.3-0.9 0.�-1.2 0.5-1.5


Capacitance, eqv. phase-to-ground µF/km 2.2 2.� 2.7 3.0 3.0

Inductance, eqv. single phase mH/km 0.032 0.029 0.025 0.022 0.022

Power rating (continuous load) at 30 kV

1 circuit/2 circuits MVA 65/130 10�/208 130/260 156/312 177/35�

Type HC-BC-CRS(WM)2Y 21/36 kV

*Conductor AC loss at Pnom depends on operation temperature, 67-79 K


Cable Core



Cryoflex® insulation mm �,7 �,7 �,7 �,7 �,7


Outer cable core diameter mm 65 69 75 81 81

Weight, HTS cable core, 3 phases kg/m �.5 5.8 6.5 7.5 8


Bending radius during laying/at termination (min) m 3/1,5 3/1,5 3/1,5 3/1,5 3/1,5

Thermal Insulation

Semi-rigid corrugated duct, ID/OD mm 8�/1�3 8�/1�3 8�/1�3 98/163 98/163


Total OD 150 150 150 170 170

Termination OD mm 160 160 160 180 180


Bending radius during laying/at termination (min) m 3/1,5 3/1,5 3/1,5 �/2 �/2

Heat leak, duct section W/m 1,5 1,5 1,5 1,7 1,7


Electrical Data


Conductor AC loss at Pnom W/m/ph 0.3 0.6 0.9 1.2 1.5


Capacitance, eqv. phase-to-ground µF/km 1,6 1,7 2,0 2,2 2,2

Inductance, eqv. single phase mH/km 0,039 0,036 0,031 0,028 0,028

Power Rating (continuous load) at 50 kV

1 circuit/2 circuits MVA 108/217 173/3�6 217/�33 260/520 29�/589

Type HT-BC-CRS(WM)2Y 42/72 kV HTS Triax™ Energy Cable

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nkt cables sells and installs the HTS Terminations and joints. We can also specify and source the cooling system as well as the monitoring

system.

nkt cables sells and installs the HTS Terminations and joints. We can also specify and source the cooling system as well as the monitoring

system.

15 kV

Triax Terminations

15 kV

Triax Joint

JointsA 15 kV HTS Triax™ joint is 3 m long with an

outer diameter of 31 cm. It contains the joints

of all three phases and a common screen.

TerminationsA 15 kV HTS Triax™ termination is 3.9 m

long. The main body is installed at a height

that gives the appropriate safety distance to

the top bolts. The picture shows an outdoor

version of the termination. nkt cables will

convert this termionation to an indoor version

on customer request.

Product Scope

Accessories

Contents Joints 5

Terminations 5

Cooling System 6

Monitoring System 7

High-current Switchgear 7

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Terminal Cooling Station

Line Cooling Station

Terminal Cooling StationTerminal Cooling Station

Line Cooling StationLine Cooling StationLine Cooling Station

Terminal Cooling Station

Terminal Cooling Station Line Cooling Station

Cooling SystemThe following cooling solutions have been

developed with Praxair Inc. The reliability

of the cable cooling system is guaranteed

through the following three features:

Redundant cooling machines in a

matrix of coolers

Eight hours of backup in a

cold storage tank

Continuous 2�/7 advanced surveillance

by a cooler operations center

The cooling power can be divided between

one or several cooling stations. The emer-

gency backup features are located in the

terminal cooling stations. The line cooling

stations are compact units of active coolers

that can be placed at intermediate locations

along the line. The distance between cooling

stations depends on the available cross sec-

tion for pumping the cooling fl uid. Distances

of 2-6 km are possible for compact sys-

tems. Closer spacing of the cooling stations

improves the energy effi ciency of the cable

systems but requires supply- and service-

points at several locations along the line.

The matrix of coolers consists of N+1

or N+2 closed-cycle, low-maintenance coo-

ling units. Cooling solutions can be develo-

ped together with major cryogenics system

suppliers to fi t individual user requirements.

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These data are treated and analyzed automa-

tically. The cable system operator is supplied

with one of four simple status commands:

0 – zero: The cable system is under

service – Do not energize

1 – “Green”: The cable system is ready

to operate

Monitoring SystemThe HTS Triax™ Energy Cable is monitored

2� h per day, 7 days a week by an advanced

surveillance system. The surveillance system

collects data on temperature, pressure and

fl ow of the cooling medium, the temperatures

of the terminations and joints load and the

operastional status of the cooling machinery

and back-up systems.

High-current Switchgearnkt cables can facilitate contacts to switchgear suppliers. The following are examples of commercially available switchgear products

from various suppliers (2007).

Examples A B C D E F G H

Type Indoor Indoor Indoor Indoor Indoor Outdoor Outdoor Outdoor

Model HVX VAH VAH VD� HD� PMI SPS2 PMI

Ventilation passive passive active active passive passive passive passive

Rated voltage kV 15 17.5 17.5 12* 2� 72 15** 1�5***

Rated current, max. A 3000 �000 8000 �000 3600 3000 �000 �000

Short-circuit, max. kA �0/50 50 50 63 �0 �0 31/�0 �0/63

BIL kV 95 95 95 125 350 110 650

making time ms 5� 90 90 7�

breaking time ms �2 �5 �5 58 �5 60 60

*available in 12, 1�.5, 36 and �0.5 kV models

**available in 15, 25,38, �8and 78 kV models

***available in 121, 1�5 and 170 kV models

2 – “Yellow”: Malfunction – Manually

disconnect w/o customer

interruption

3 – “Red”: Urgent malfunction –

Automatic disconnect with

customer interruption

The service provider can perform remote dia-

gnostics through an advanced monitoring sys-

tem with complete access to all system sensors.

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Making it easy …The HTS Triax™ Energy Cables are well-

suited for installation in high-density city

areas where disturbances to traffi c and

infrastructure need to be kept to a minimum.

nkt cables has developed an innovative

new installation procedure, the HTS Two-

PreludeIn the prelude to the installation procedure,

the trench is excavated, PE ducts are instal-

led, and concrete or other suitable protection

is installed. The trench is then re-closed

with rock, sand or soil. There are no special

requirements on the thermal properties of

the refi ll, since the HTS Triax™ Energy Cable

does not release heat into the trench.

In the case of a retrofi t into an existing duct,

the old cables are removed through access

holes located at the old cable joints. The old

cable is sent for recycling, while the duct is

cleaned and lubricated.

Step™ Installation, where the cable core can

be installed separately from the thermally

insulating tube. This gives higher fl exibility

and quicker response to the requirements of

each installation site, and above all, it reduces

the number of cable joints.

Step oneIn the fi rst installation step, the thermally

insulating tube (the “Cryostat”) is provided

in lengths of 100-700 m. Shorter sections

are joined together as they are pulled into

the PE duct, for distances of 500-700 m at

a time (Fig.1). The cryostats are provided as

fl exible or rigid sections, depending on the

curvature of the cable route. Spacings are

left between successive cryostats.

Step twoThe HTS Triax™ cable core is provided in

lengths up to 2 km. It is inserted at one end

of the trench, and pulled through several cry-

ostat sections, with the help of cable pushers

placed in the spacings between cryostat sec-

tions (Fig. 2). As soon as the cable is in place,

the cryostat sections are joined together,

and the access holes can be closed. Cable

over-length is introduced through a patented

procedure so that the thermal shrinkage can

be accommodated. The work outside of the

station areas is now complete and there are

no further disturbances in the public space.

Culmination The HTS Triax™ Energy Cable system is

completed by terminating the cable in the sta-

tion areas, and by connecting and starting the

cooling system.

With nkt cables’ HTS Two-Step™ Installation

approach, the cable joints can be spaced up

to 2 km apart and there is only one joint per

three-phase cable. Any open trenches can be

re-closed even before the cable installation

starts, and the access-holes need to stay

open for only a minimum amount of time.

Fig. 1

Fig. 2

Installation and Protection

HTS Two-Step™ Installation

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To sum it up: Making use of nkt cables’

expertise and engineering assistance already

in the design stage, is the fi rst step for

smooth realization of the project.

A smaller parallel duct is installed near the

cryostat. Optical fi bres are pulled into the

duct and used for distributed temperature

sensing. Any damage to, or degradation in

the cryostat will show up as a temperature

signal at the location of the damage.

Optionally, some of the fi bres can be used for

communication. Fibres for thermal monitoring

can be provided as external skid wires in the

case of a retrofi t into an existing duct where

no parallel duct is available.

Service ContractsService contracts are offered where the task

of maintaining the cable installations in good

condition is transferred to the shoulders of

nkt cables. With this offer it is ensured that

skilled personnel takes care of the supercon-

ducting cables. Regular checks of the condi-

tions and, if necessary, initiation of remedial

action at an early stage guarantee the value

of the assets.

Thermal Monitoring and Damage Detection

Engeneering assistancenkt cables can provide advanced enginee-

ring services already in the early planning

stage of a project. Our engineers can provide

electrical data, thermal simulations and

proposed cable-system layouts as a part

of early system studies to evaluate the best

cable solutions. Making use of nkt cables’ ex-

pertise and engineering assistance already in

the design stage is the fi rst step for a smooth

realization of your project.

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Testing of cables and accessories com-

prises routine and special tests performed

in the factory as well as tests on site after

completion of the installation. These tests

are performed in compliance with customer

requirements and various national and inter-

national standards like IEC, EN, VDE, NF, BS,

NEN, AEIC and others.

Type tests and long-term tests have been

made on components and also for qualifi ca-

tion of complete cable systems. Newly devel-

op ed cables and accessories are subjected

to tests in the fi eld lasting several years and

comprising electrical and thermal stressing

far beyond of what can be expected during

normal operation.

A complete recycling conceptfor all recyclable cable types By virtue of �0 years of experience within cable

recycling, we are the only European cable

manufacturer with a complete recycling con-

cept for all recyclable cable types. We recycle

cable waste at our environmentally approved

recycling plant in Stenlille. Our plant in Stenlille

is among the fi rst 100 Danish companies with

DS/EN ISO 1�001 certifi cation.

We take our environmental responsibility

seriously, for which reason environmental

considerations play an important role in all

departments of our company, irrespective of

it being a question of product development,

production or working processes or removal

of worn-out products.

For us it is not only a question of considering

the environment when recycling and recover-

ing cable waste. Environmental considerations

are also decisive in our selection of materials

and suppliers as well as in the planning of

production processes. In this way we minimize

the environmental impact related to the pro-

duct life cycle: production - use - removal.

Of course we also assist our customers to

act in the best interest of the environment.

Please contact us to learn how you can best

dispose of your cable waste.

Quality from beginning to end Quality from beginning to end is an essential

part of nkt cables’ manufacturing philosophy.

This is ensured by a combination of certifi ed

quality control throughout the production

process and the use of raw material from

approved sub-suppliers only. This places

nkt cables in a fi ne position in international

competition and secures fl exibility to adapt

rapidly to changing market requirements.

nkt cables is of course certifi ed according to

ISO 9001.

We know how nkt cables’ laboratory researches in and

develops environmentally sustainable plastic

materials for cables and leads and also

handles quality control of raw materials and

fi nished goods. The HV laboratories perform

electrical tests on the cables.

nkt cables’ technicians are internationally

recognized for their specialized knowledge in

compound development. nkt cables was the

fi rst company in the world to introduce lead-

free PVC cables in which the poisonous lead

stabilizers had been replaced by the relatively

harmless calcium and zinc stabilizers. The

idea was so good that the Danish Minister for

Environment and Energy prohibited marke-

ting cables with leaded PVC after December

1, 2001. Research plays an important role

in all parts of nkt cables. Recently, NKT

Research, nkt cables’ sister company, carried

out revolutionary research in materials tech-

nology. This research enabled nkt cables to

begin the production of fi bre optical cables

as early as in 1980 and to put the world’s

fi rst superconducting HV cable in a public

network in 2001.

Testing

Research & Development & Innovation

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Quality Assurance and Environmental Responsibility

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nkt cables GmbH

Schanzenstraße 6 – 20

D-51063 Cologne (Germany)

Phone +�9 (0)2 21- 676-0

Fax +�9 (0)2 21- 676-26�6

[email protected]

www.nktcables.com

Direct contact for your region:

Central EuropeCarsten Wolff

Phone +�9 (0)2 21- 676 -20 31

[email protected]

Representation offices

Belgium: +32 / �76 981 �29

Netherlands: +31 / 6�6095035

France: +33 / 616 12 15 ��

Scandinavia and UKBrian Scott

Phone +�5 / 5966 1213

[email protected]

Representation office

GB: +�� / 783�0 569 28

InternationalHans Damm Jensen

Phone +�9 (0)2 21- 676 -20 76

[email protected]

Representation offices

Moscow: +7 (�95) 777�858

UAE: +971 2 ��93550

nkt cables Spain S. L.Edifici Testa

Alcalde Barnils 6�-68

escal B, 3º piso, local 3

Sant Cugat del Valles

E-0817� Barcelona, Spain

Phone: +3� / 93 59 07 017

Fax: +3� / 93 67 50 528

[email protected]

Documents

HTS Triax™ Energy Cable Systems