qualification procedure of hvdc cables
TRANSCRIPT
Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Qualification procedure of
HVDC cables
Tutorial T2
By Marc Jeroense - ABB
Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
1
Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Content
• Introduction
• Cable types
• What should a qualification aim for?
• What different qualification methods exist?
• Mechanical testing (Electra 171)
• DC paper cables (Electra 189)
• DC Extruded cables (TB 496)
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Content
• Introduction
• Cable types
• What should a qualification aim for?
• What different qualification methods exist?
• Mechanical testing (Electra 171)
• DC paper cables (Electra 189)
• DC Extruded cables (TB 496)
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Cable types
• We limit ourselves to DC cables
– Paper insulated cables
• Mass Impregnated (MI), oil-filled, gas pressure
– Extruded cables
• Cross linked polyethylene
• Thermoplastic
• Filled
• Other
AC..
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Content
• Introduction
• Cable types
• What should a qualification aim for?
• What different qualification methods exist?
• Mechanical testing (Electra 171)
• DC paper cables (Electra 189)
• DC Extruded cables (TB 496)
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
What should a qualification aim for in general?
1. To reflect the situation the cable system will experience in
real life
2. To adress the functional weak points of the cable system with
respect to point 1
?
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
What should a qualification aim for in general?
Example:
• Lightning impulse
– Will the cable system experience it?
– Test it / qualify it?
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
What should a qualification aim for in general?
Example:
• Temperature
– Low temperature for MI cable
– High temperature for Extruded DC cable
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
What should a qualification aim for in general?
• Low temperature for MI DC cable– Test at low environmental temperature
Voltage U
Current I
Time
Temperature Increase
Pressure Increase
Fluid Flow
Temperature Decrease
Partial Backflow of Fluid
Pressure Decrease
Void Creation
Positive Expansion Coefficient
Low Viscosity
High Viscosity
Voids in
•butt-gaps
•between paper layers
•inside paper
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
What should a qualification aim for in general?
• High temperature for Extruded DC cable
– Test at high environmental temperature
Illustrative example…
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Content
• Introduction
• Cable types
• What should a qualification aim for?
• What different qualification methods exist?
• Mechanical testing (Electra 171)
• DC paper cables (Electra 189)
• DC Extruded cables (TB 496)
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
What different qualification methods exist?
• The method depends on the purpose!
– Development test (not qualification!)
– Prequalification Test
– Type Test
– Sample Test
– Routine Test
– Factory Acceptance Test
– After Laying Test
Not on physical lengths
that will be delivered
On physical lengths that
will be deliveredException for sample test
12
Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
What different qualification methods exist?
• Development test (not qualification!)– TB496 – ”Tests made during the development of the cable system”
• Prequalification test– TB496 – ” Test made before supplying on a general commercial basis a type of cable
system covered by this recommendation, in order to demonstrate satisfactory long term
performance of the complete cable system.
NOTE 1: The prequalification test need only be carried out once unless there is a substantial change in the cable system with
respect to material, manufacturing process, design or design electrical stress levels.
NOTE 2: A substantial change is defined as that which might adversely affect the performance of the cable system. The supplier
should provide a detailed case, including test evidence, if modifications are introduced, which are claimed not to constitute a
substantial change.
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
What different qualification methods exist?
• Type Test– TB496 – ”Tests made before supplying on a general commercial basis a type of cable
system covered by this recommendation, in order to demonstrate satisfactory
performance characteristics to meet the intended application.”
NOTE: Once successfully completed, these tests need not be repeated, unless changes are made in the cable or accessory with
respect to materials, manufacturing process, design or design electrical stress levels, which might adversely change the
performance characteristics.
• Sample Test– TB496 – ”Tests made by the manufacturer on samples of complete cable or components
taken from a complete cable or accessory, at a specified frequency, so as to verify that
the finished product meets the specified requirements.”
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
What different qualification methods exist?
• Routine Test– TB496 – ”Tests made by the manufacturer on each manufactured component (length of
cable or accessory) to check that the component meets the specified requirements.”
• Factory Acceptance Test– As ”Routine Test”, but on the complete delivery length
• After Laying Test– T496 – “Tests made to demonstrate the integrity of the cable system as installed.”
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Content
• Introduction
• Cable types
• What should a qualification aim for?
• What different qualification methods exist?
• Mechanical testing (Electra 171)
• DC paper cables (Electra 189)
• DC Extruded cables (TB 496)
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Mechanical testing (Electra 171)
• Recommendations for Mechanical Tests on
Sub-marine Cables
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Mechanical testing (Electra 171)
• Electrical qualification tests adress the entire in-service life
time of the cable
• Mechanical qualification tests adress the laying and/or
recovery operation
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Mechanical testing (Electra 171)
• Coiling Test
• Tensile Bending Test
• Tensile Test
• ”Water Tests”– Internal Water Pressure Test
– External Water Pressure Test
– Conductor Water Penetration Test
– Metal Sheath Water Penetration Test
– Radial Water Penetration Test for Joints
TB490
Electra 171 Paper cables
Extruded cables
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Mechanical testing (Electra 171)
• Tensile Bending Test
• Tensile Test
2 ×T
Pulley
Rotating drum
Joint
Cable heads
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Mechanical testing (Electra 171)
• Calculation of test forces– related to laying and recovery forces
< 500 m
≥ 500 m
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Content
• Introduction
• Cable types
• What should a qualification aim for?
• What different qualification methods exist?
• Mechanical testing (Electra 171)
• DC paper cables (Electra 189)
• DC Extruded cables (TB 496)
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
DC paper cables (Electra 189)
• Recommendations for Tests of Power
Transmission DC Cables for a Rated Voltage up
to 800 kV
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
DC paper cables (Electra 189)
• Routine Tests– High Voltage Test at Works (1.8 x U0 dc 15 minutes) – Full length
– Conductor Resistance Test – Full length or sample
– Capacitance Test – Sample length
– Power Factor Test – Sample length
• No prequalification (Long Term Test)
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
DC paper cables (Electra 189)
• Type Test, remember �
– Example below:
MI cables
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
DC paper cables (Electra 189)
• Type Test– 10 load cycles (8/16 hours) at + 1.8 x U0
– 10 load cycles (8/16 hours) at - 1.8 x U0
– 10 load cycles (8/16 hours) with polarity reversals at +1.4 x U0
• Every 4th hour the polarity shall be reversed
• One reversal shall coincide with the cessation of loading current in every loading
cycleBackbone of a Type Test:•Bending Test
•Load Cycle Test and Polarity Reversal Test•Switching Surge Withstand test
•Lightning Impulse Withstand Test
•External Water Pressure Withstand Test
•Visual Inspection
Current I
Voltage U
Voltage U
Current I
TimeEtc.
0
0
-KU0
+KU0
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
DC paper cables (Electra 189)
• Superimposed Impulse Voltage Test
• Switching (TCR = 250 μsec, T2=2500 μsec)
– 10 positive switching surges superimposed on a negative voltage of U0
– 10 negative switching surges superimposed on a positive voltage of U0
• Lightning (TCR = 1-5 μsec, T2=50 μsec)
– 10 positive switching surges superimposed on a negative voltage of U0
– 10 negative switching surges superimposed on a positive voltage of U0
Peak level Up1
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
DC paper cables (Electra 189)
• After Laying Test– Negative voltage of 1.8 U0 during 15 minutes
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Content
• Introduction
• Cable types
• What should a qualification aim for?
• What different qualification methods exist?
• Mechanical testing (Electra 171)
• DC paper cables (Electra 189)
• DC Extruded cables (TB 496)
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
RECOMMENDATIONS FOR TESTING
DC EXTRUDED CABLE SYSTEMS FOR
POWER TRANSMISSION AT A RATED
VOLTAGE UP TO 500 kV
Convenor: Bjørn Sanden (NO)
Secretary: Jérôme Matallana (NO)
TUTORIAL B1.32 – TB 496
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Content
• Scope of work
• Revision with respect to TB 219
• Overview of tests
• Technical basis – Definition of test parameters
• Prequalification tests
• Type tests
• Routine tests
• Sample tests
• After installation tests
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
WG Scope of work (1)
• Background
– TB 219 issued in February 2003 addresses HVDC extruded cable systems
up to 250 kV
– Due to commercially available HVDC systems above 250 kV an update to
500 kV was necessary
• General scope
– Prepare a recommendation for testing DC extruded cable systems up to
500 kV
– Step 1: review TB 219 principles with respect to eventual inadequacy for
DC voltages beyond 250 kV
– Step 2: develop a new recommendation (new TB)
• Working Group duration: 3 years (2009-2011)
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
WG Scope of work (2)
• Scope of work
– Survey of laboratory and operational experience
– Consider extrapolation of TB 219 principles to 500 kV
– Consider both submarine and land applications and aspects related to
testing of long lengths
– Electrical, thermal and mechanical aspects
– Refer to appropriate standards and recommendations
– The recommendation to be released shall at least:
• Cover Prequalification tests, Type tests, Routine tests, Sample tests, After
installation tests
• Consider a range of type approval
• Take into account laying and operational conditions when developing the
test conditions and requirements
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Survey of laboratory and operational
experience
• At the time of preparing this recommendation
– Laboratory experience at voltages up to and including 500 kV
– Operating experience limited to 200 kV
– Commercial Contracts awarded at a voltage level up to 320 kV
– A further increase in voltage level is to be expected and this
recommendation will therefore cover voltages up to 500 kV.
– It is important to emphasise that the lack of operational experience
above 200 kV and the limited number of tests at higher voltage levels
represent an uncertainty in the preparation of this recommendation.
Consequently new relevant knowledge that emerges from increased
testing and/or service experience at higher voltages may necessitate
new revisions of this recommendation in the future.
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
WG B1.32 Members
COUNTRY NAME
CANADA Allen MacPhail
DENMARK Thomas Kvarts
FRANCE Laurent Benard
ITALY Ernesto Zaccone
JAPAN Seishi Hirano
KOREA Jung-Nyun Kim
NETHERLAND Riccardo Bodega
NORWAY Jerome Matallana (Secretary)
NORWAY Bjørn Sanden (Convenor)
SWEDEN Marc Jeroense
SWITZERLAND Detlef Wald
UK Roman Svoma
CORRESPONDING MEMBERS:
AUSTRALIA Joska Ferencz
ITALY Luigi Colla
US Steve Eckroad
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Revisions with respect to TB 219 (1)
• Discussion on technical basis
– Determination of voltage factors at V > 250 kV ?
– Inverse power law and “n” values at V > 250 kV ?
– Time constants at V > 250 kV, resistivity of insulating materials ?
– Examination of TB 303 outcome and relevance for HVDC extruded
– WG consensus: TB 219 principles shall cover higher voltage levels until
some discrepancies are displayed by operational and/or lab experience
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Revisions with respect to TB 219 (2)
• Main changes:
– Voltage range extended to 500 kV
– General text update to take into account latest revisions of IEC
60840/62067 wording
– Range of approval of both prequalification and type tests have been
revised
– Load cycle blocks of PQ test refers to number of cycles instead of number
of days
– Duration of cycles updated to comply with IEC requirements instead of
exactly 24 h or 48 h load cycles (i.e. at least 8 h heating etc…). Adopted
wording is “24 hours” or “48 hours” load cycles
– Recommendations for routine / sample tests on cable accessories have
been included
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Scope of the recommendation
• This document recommends a series of tests on extruded cables
for DC power transmission systems (land or submarine cables
with their accessories in fixed installations) up to and including
500 kV.
– Recommendation addresses 2 type of HVDC systems
• LCC (Line Commutated Converters) � Classic HVDC, thyristor technology,
cable system subjected to polarity reversals
• VSC (Voltage Source Converters) � New generation conversion technology
based on IGBT electronics, cable system not subjected to polarity reversals
– Extruded cable systems
• Within the scope of these recommendations “extruded” shall mean either
filled (e.g. with mineral or carbon) or unfilled and either thermoplastic (e.g.
polyethylene, etc.) or thermoset (e.g. crosslinked polyethylene, ethylene
propylene rubber, etc.) insulations.
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Overview of proposed tests (1)
• Where applicable, all definitions are in line with IEC 60840 and
IEC 62067
• Development Tests
– Tests made during the development of the cable system
– The manufacturer should complete all analyses and development testing
prior to commencing the prequalification test. The precise nature and
extent of development work and analyses shall be left to the discretion
of the manufacturer, but may include the following:
• Resistivity = f(E,T), breakdown strength, space charge properties
• DC field distribution within the insulation systems through resistivity
coefficients
• Long term stability, ageing effect assessment
• Sensitivity of electric field to variations in• Cable dimensions
• Material composition
• Process conditions
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Overview of proposed tests (2)
• Prequalification tests (PQ tests)
– Tests made before supplying on a general commercial basis
a type of cable system covered by this recommendation, in
order to demonstrate satisfactory long term performance
of the complete cable system.
• The prequalification tests need only be carried out once unless
there is a substantial change in the cable system with respect to
material, manufacturing process, design or design electrical stress
levels.• A substantial change is defined as that which might adversely affect the performance of
the cable system
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Overview of proposed tests (3)
• Type tests
– Tests made before supplying on a general commercial basis
a type of cable system covered by this recommendation, in
order to demonstrate satisfactory performance
characteristics to meet the intended application.
• Once successfully completed, these tests need not be repeated,
unless changes are made in the cable or accessory with respect to
materials, manufacturing process, design or design electrical stress
levels, which might adversely change the performance
characteristics.
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Overview of proposed tests (4)
• Routine tests
– Made by the manufacturer on manufactured component, cable length or
accessory, to check that it meets the specified requirements
• Sample tests
– Made by the manufacturer on samples of complete cable or components
taken from a complete cable or accessory at a specified frequency to
check that the finished product meets the specified requirements
• After installation tests
– Made to demonstrate the integrity of the cable system as installed
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Technical basis (1)
• Voltage factors
– Based on available V-t characteristics for DC operation
– Inverse power law provided a conservative basis for the work
– A value of n = 10 was selected in TB 219 and kept by WG B1.32 since no
significant finding allowed to amend this approach today
consttV n =⋅
where:
V : voltage
t : time
n : life exponent from V-t characteristics
Test voltage Vdc is:
10 KVVdc ⋅=
where:
V0 : system voltage
K1 : test voltage ageing factor
n
t
tK
1
01 =
t0 design life t1 test duration
Inverse power law
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Technical basis (2)
• Test factors up to 500 kV DC
Prequalification Test Type Test
Design Life, t0 (years) 40 40
Test Duration, t1 (days) 360 30
Test Voltage Aging Factor, K1 10 360/36540 ⋅ 10 30/36540 ⋅
Test Factor 1.45 1.85
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Technical basis (3)
• Time constants
– Determine the duration of test sequences (steady state aimed at)
– Resistivity of insulation materials vs. E and T
– Higher resistivity materials may be developed and a review of test block
durations may be required in the future
Temperature
(°°°°C)
εεεε(F/m)
ρρρρ(Ω.m)
Time for stability, 10 ττττ(hours)
20 2x10-11<ε< 3x10-11 1015< ρ< 5x1016 55<10 τ < 4300
60 2x10-11<ε< 3x10-11 2x1013<ρ< 5x1014 1< 10 τ< 43
90 2x10-11< ε< 3x10-11 1012<ρ< 5x1013 0.06< 10 τ < 4.3
Condition TemperatureTesting time
(Days)
Time for stability, 10 ττττ(Days)
Zero load
(Prequalification)
Ambient temperature
(20±15°C)At least 120 2.3<10 τ < 180
48 Hour Load Cycle:
(Type Approval)
At least maximal conductor
temperature
(60°C to 90°C
depending on
manufacturer design)
1
(heating period)0.003<10 τ <1.8
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Test objects
0.5 m cable included in the
Accessory test object
test object Cable. Minimum 10 m.
test object
Termination
minimum 5 m cable
between Accessory
test objects test object
Joint
test object
Joint
test object
Termination
Example of test loop
minimum 5 m cable between
Accessory test objects
Back to type test
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
DC tests voltages, examples
Rated
voltage
Type test
Routine tests
PQ test: Load cycle test
Type test: Polarity reversals
After installation test
PQ test: Polarity
reversals
U0 (kV) UT (kV) = 1.85xU0 UTP1 (kV) = 1.45xU0 UTP2 (kV) = 1.25xU0
300 555 435 375
320 592 465 400
400 740 580 500
500 925 725 625
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Impulse tests voltages
VSC, same polarity positive
switching impulse
U0
t
LCC or VSC, positive lightning impulse LCC or VSC, negative lightning impulse
U0
- UP1
t
kV
- U0
UP1
t
kV
UP2,S
kV
LCC or VSC, opposite polarity
negative switching impulse
t
- UP2,O
kV
U0
VSC, same polarity negative
switching impulse
kV
- UP2,S- U0
kV
t
- U0
UP2,O
t
LCC or VSC, opposite polarity
positive switching impulse
• Lightning impulse (LI)
– UP1 = 1.15 x max. absolute value of
the design LI voltage when LI has
opposite polarity to DC
• Switching Impulse (SI)
– UP2,S = 1.15 x max. absolute value of
the design SI voltage when SI has
same polarity as DC
– UP2,O = 1.15 x max. absolute value of
the design SI voltage when SI has
opposite polarity as DC
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Thermal parameters
• Tcond,max
– Maximum temperature the cable conductor is designed to operate
– Stated by the supplier
• ∆Tmax
– Maximum temperature drop over the cable insulation in steady state at
which the cable is designed to operate
– The semiconducting screens are not included
– This value is stated and calculated by the supplier
– The supplier shall correlate this design value with data measured during
testing
• Ambient temperature
– (20 ± 15) °C
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Thermal conditions for tests (1)
• Load Cycles (LC)
– Consist of a heating period followed by a cooling period
– “24 hours” load cycles
• At least 8 h heating
• During at least the 2 last hours of heating
– Tcond ≥ Tcond,max
– ∆T ≥ ∆Tmax
• At least 16 h of natural cooling
– “48 hours” load cycles
• At least 24 h heating
• During at least the 18 last hours of heating
– Tcond ≥ Tcond,max
– ∆T ≥ ∆Tmax
• At least 24 h of natural cooling
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Thermal conditions for tests (2)
• High Load (HL)
– Consists of a continuous heating period
– Within the first 8 hours, the following conditions shall be achieved
• Tcond ≥ Tcond,max
• ∆T ≥ ∆Tmax
– If, for practical reasons, these conditions are not met within 8 h, a longer
time can be used, although not constituting as being part of the test period
• Zero load (ZL)
– No heating applied
• Prior to impulse tests
– The following conditions shall be met for at least 10 h before impulses
• Tcond ≥ Tcond,max
• ∆T ≥ ∆Tmax
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Specific test conditions (1)
• Polarity reversal test (PR) – “24 hours” load cycles
– LC sequence and voltage as described previously
– Starting with positive polarity
– 3 polarity reversals evenly distributed shall be performed during a “24
hours” load cycle (therefore at least 8 h between reversals)
– One reversal shall coincide with the cessation of heating current
– Polarity reversal performed within 2 minutes. If, for practical reasons,
this cannot be achieved, the duration shall be agreed between
customer and supplier
• Superimposed impulse voltage tests
– Prior to impulse tests, the temperature conditions defined in the
previous slide shall be achieved but the DC voltage U0 shall also be
applied for at least 10 h
– This was selected to reflect the electric dynamics of extruded
insulations under HVDC
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Specific test conditions (2)
• Check on insulation thickness of cable (IEC 60811-1-1)
– Prior to all electrical tests
– Consistency with IEC 60840 and IEC 62067 standards
• Return cable – voltage definitions
– URC,AC
• Maximum voltage a return cable can experience due to temporary
damped AC overvoltage (typically due to a commutation failure)
• The nature of the overvoltage depends upon the configuration of the
HVDC link and needs to be calculated for each case
– URC,DC
• Maximum DC voltage in normal operation
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Jicable-HVDC’13 - European Seminar on Materials for HVDC cables and accessories
Perpignan France – 18th – 20th November 2013
Prequalification Test
• The prequalification test is intended to indicate the long-term
performance of the complete cable system and should
normally be carried out after the development tests have
been completed.
• The prequalification test needs only be carried out once,
unless there is a substantial change in the cable system with
respect to materials, manufacturing processes, construction
or design parameters.
– A substantial change is defined as that which might adversely affect
the performance of the cable system.
– The supplier shall provide a detailed case including test evidence if
modifications are introduced, which are claimed not to constitute a
substantial change.
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Prequalification Test
• Range of approval– The rated voltage U0 is not more than 10% higher than that of the tested cable system.
– The calculated average electrical stress in the insulation (given by U0 divided by the nominal
insulation thickness) is less than or equal to that of the tested system.
– The calculated Laplace electrical stress at U0 (using nominal dimensions) at the cable
conductor and insulation screen is less than or equal to that of the tested system.
– The maximum conductor temperature Tcond,max is less than or equal to that of the tested
system.
– The maximum temperature drop across the insulation layer ∆Tmax (excluding the
semiconducting screens) is less than or equal to that of the tested system.
– A cable system prequalified according to this recommendation for LCC is also prequalified
for VSC. A cable system prequalified according to this recommendation for VSC is not
prequalified for LCC.
– An unarmoured cable prequalified according to this recommendation prequalifies an
armoured cable and vice versa
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Prequalification Test
• Comments to the range of approval– Cigré TB 303 is a relevant document to assess the need for further PQ testing but the
concept of Extension of Qualification cannot be implemented for HVDC extruded given the
current state-of-the-art
– For the sake of clarity, no consideration of DC electrical stress involved in this range of
approval
• Establishing the DC stress involves calculations based on material properties that are established
from non standardised measurements, e.g. conduction current as a function of temperature and
electrical stress
• DC stress is a critical design criteria and each supplier must have detailed knowledge of their cable
system
– The use of a large conductor cross-section is recommended to cover thermo-mechanical
aspects
– PQ tests performed according to TB 219 are valid
– The aim of the impulse test at the end of the PQ test sequence is to check the integrity of
the cable system. It does not qualify the system for a given impulse level. Project-specific
impulse levels should be qualified during the type test
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Prequalification Test
• General
– At least 100 m of cable including at least one complete accessory of each
type should be tested
– Where appropriate mechanical preconditioning may be considered
before starting the PQ test
– Minimum duration of voltage test is 360 days
• Test arrangement
– Cable and accessories shall be assembled according to manufacturer's
instructions
– The test loop should reflect the installation conditions
• Sequence of tests
– Long duration voltage test
– Superimposed impulse voltage test
– Examination
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Prequalification Test
LC LC LC+PR HL HL ZL LC LC LC+PR S/IMP
Number of
cycles or days
30
cycles
30
cycles
20
cycles
40
days
40
days
120
days
30
cycles
30
cycles
20
cyclesNot applicable
Test Voltage
+ - + - - + -UP2,O = 1.2 x U0
UP1 = 2.1 x U0*UTP1 UTP1 UTP2 UTP1 UTP1 UTP1 UTP1 UTP1 UTP2
LC=Load Cycle, HL=High Load, PR=Polarity Reversal, ZL=Zero Load, S/IMP=Superimposed Impulse Test.
* If required
Long duration voltage test, LCC sequence
Long duration voltage test, VSC sequence
LC LC HL HL ZL LC LC S/IMP
Number of
cycles or days
40
cycles
40
cycles
40
days
40
days
120
days
40
cycles
40
cyclesNot applicable
Test Voltage+ - + - - + - UP2,O = 1.2 x U0
UP1 = 2.1 x U0*UTP1 UTP1 UTP1 UTP1 UTP1 UTP1 UTP1
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Prequalification Test
• Impulse test levels
– UP2,O = 1.2 x U0
– UP1 = 2.1 x U0 (agreement between customer and supplier)
– Tests shall be performed on the complete assembly or on one or more
cable samples with a minimum total active length of 30 m cut from the
complete assembly
• Note on success criteria - Interruptions
– In case of interruption due to external factors the test may be resumed
• If the interruption is longer than 30 minutes the specific lost load cycle shall
be repeated
• If the interruption happens during a constant load period and is longer than
30 minutes, the day the interruption occurred shall be repeated
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-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Tes
t Vol
tage
(kV
)
Elapsed Time (days)
VSC prequalification test schedule
Example: Prequalification Test VSC, U0 = 320 kV
Load Cycles :
• + 1.45 x UO 40 cycles
• 8 h heating / 16 h cooling
(applied current leads to design temperature)
• Tmax & ∆Tmax for at least 2 h
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Example: Prequalification Test VSC, U0 = 320 kV
-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Tes
t Vol
tage
(kV
)
Elapsed Time (days)
VSC prequalification test schedule
Load Cycles :
• - 1.45 x UO 40 cycles
• 8 h heating / 16 h cooling
(applied current leads to design temperature)
• Tmax & ∆Tmax for at least 2 h
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-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Tes
t Vol
tage
(kV
)
Elapsed Time (days)
VSC prequalification test schedule
Example: Prequalification Test VSC, U0 = 320 kV
High Load :
• + 1.45 x UO 40 days
• Continuous Heating
(applied current leads to design temperature)
• Tmax & ∆Tmax
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Example: Prequalification Test VSC, U0 = 320 kV
-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Tes
t Vol
tage
(kV
)
Elapsed Time (days)
VSC prequalification test schedule
High Load :
• - 1.45 x UO 40 days
• Continuous Heating
(applied current leads to design temperature)
• Tmax & ∆Tmax
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Example: Prequalification Test VSC, U0 = 320 kV
-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Tes
t Vol
tage
(kV
)
Elapsed Time (days)
VSC prequalification test schedule
Zero Load :
• - 1.45 x UO 120 days
• No Heating
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Example: Prequalification Test VSC, U0 = 320 kV
-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Tes
t Vol
tage
(kV
)
Elapsed Time (days)
VSC prequalification test schedule
Load Cycles :
• + 1.45 x UO 40 cycles
• 8 h heating / 16 h cooling
(applied current leads to design temperature)
• Tmax & ∆Tmax for at least 2 h
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Example: Prequalification Test VSC, U0 = 320 kV
-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Tes
t Vol
tage
(kV
)
Elapsed Time (days)
VSC prequalification test schedule
Load Cycles :
• - 1.45 x UO 40 cycles
• 8 h heating / 16 h cooling
(applied current leads to design temperature)
• Tmax & ∆Tmax for at least 2 h
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Example: Prequalification Test VSC, U0 = 320 kV
-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Tes
t Vol
tage
(kV
)
Elapsed Time (days)
VSC prequalification test schedule
Impulse superimposed to DC Test :
• after min. 360 days DC testing
• U0 applied for at least 10 hours
• Tmax & ∆Tmax for at least 10 hours
• Waveform according to IEC 60230
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Type Test
• Range of approval (1)– The actual designs, materials, manufacturing processes and service conditions for
the cable system are in all essential aspects equal.
– All service voltages, U0, UP1, UP2,S and UP2,O (URC,AC and URC,DC in case of return
cable), are less than or equal to those of the tested cable system.
– The mechanical stresses to be applied during preconditioning are less than or
equal to those of the tested cable system.
– The service maximum conductor temperature Tcond,max is less than or equal to
that of the tested cable system.
– The maximum temperature drop across the insulation layer ∆Tmax (excluding the
semiconducting screens) is less than or equal to that of the tested cable system.
– The actual conductor cross-section is not larger than that of the tested cable
system.
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Type Test
• Range of approval (2)– The calculated average electrical stress in the insulation (given by U0 divided by
the nominal insulation thickness) is less than or equal to that of the tested
system.
– The calculated Laplace electrical stress (using nominal dimensions) at the cable
conductor and insulation screen is less than or equal to that of the tested system.
– A cable system qualified according to this recommendation for LCC is also
qualified for VSC provided the switching impulse withstand tests at ±UP2,S
voltage levels as specified in § 4.4.3.3 are carried out. A cable system qualified
according to this recommendation for VSC is not qualified for LCC
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Type Test
• Comments to the range of approval– For the sake of clarity, no consideration of DC electrical stress involved in this
range of approval
• Establishing the DC stress involves calculations based on material properties that are
established from non standardised measurements, e.g. conduction current as a
function of temperature and electrical stress
• DC stress is a critical design criteria and each supplier must have detailed knowledge of
their cable system
– Non-electrical tests need not be carried out on samples from cables of different
voltage ratings and/or conductor cross-sections unless different materials and/or
different manufacturing processes are involved
– If the combination of materials applied over the screened core is different from
that of the cable on which type tests have been carried out previously, repetition
of ageing tests on pieces of complete cable for compatibility purposes may be
required
– Type tests successfully performed according to TB 219 are valid
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Type Test
• Test objects
– All components of the cable system shall be subjected to type test
– Different parts of a system could be in different loops
• Non-electrical type tests
– The cable system shall be applied to non-electrical type testing as
specified in IEC 62067 Ed. 2
– Land cable systems including water blocking featurs shall be subjected to
a water penetration test as specified in IEC 62067 Ed. 2
– Submarine cable systems shall be subjected to a water integrity test as
specified in Electra 189, April 2000
– Cables with metallic earthing connections through plastic sheath shall be
subjected to the relevant test in Electra 189, April 2000
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Type Test: Electrical Type Test
• Mechanical preconditioning– Appropriate for land or submarine cable
application
– Aim: subject the test object to the maximum
mechanical stress experienced during handling,
installation and recovery
– Land cable systems: IEC 62067 Ed. 2
– Submarine cable systems: Electra 171
• Electrical tests sequence– Load cycles tests
– Superimposed impulse tests
– Subsequent DC test
– Test of outer protection for joints
– Examination
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Type Test
• Note on success criteria - Interruptions
– In case of interruption caused by external factors, the test may be
resumed
• Interruption > 30 min: the specific lost load cycle shall be repeated
• Interruption > 24 h: the actual test block shall be repeated (“24 hours” LC
block, “24 hours” LC block with polarity reversals, “48 hours” LC block)
• Note on rest periods between test blocks
– Minimum rest periods of 24 h are recommended between test blocks of
different polarities
– No voltage, heating applied (at the discretion of the manufacturer)
– The goal is to relax the electrical / eventually mechanical stresses
– Rest periods do not apply to individual polarity reversals in the polarity
reversal blocks
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Type Test VSC
• VSC electrical test sequence
– 12 x ”24 hours” Load Cycles at -UT
– 12 x ”24 hours” Load Cycles at +UT
– 3 x ”48 hours” Load Cycles at +UT
– Superimposed switching impulse withstand test
• Test loop at U0 , 10 consecutive impulses to UP2,S
• Test loop at U0 , 10 consecutive impulses to -UP2,O
• Test loop at -U0 , 10 consecutive impulses to -UP2,S
• Test loop at -U0 , 10 consecutive impulses to UP2,O
– Superimposed lightning impulse withstand test (if required)
• Test loop at U0 , 10 consecutive impulses to –UP1
• Test loop at -U0 , 10 consecutive impulses to UP1
– Subsequent DC test
• 2 h at –UT , no heating
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Type Test LCC (1)
• LCC electrical test sequence
– 8 x ”24 hours” Load Cycles at -UT
– 8 x ”24 hours” Load Cycles at +UT
– 8 x ”24 hours” Load Cycles with polarity reversals at UTP1
– 3 x ”48 hours” Load Cycles at +UT
– Superimposed switching impulse withstand test
• Test loop at U0 , 10 consecutive impulses to -UP2,O
• Test loop at -U0 , 10 consecutive impulses to UP2,O
– Additional superimposed switching impulse withstand test for LCC
systems intended to be qualified for VSC application
• Test loop at U0 , 10 consecutive impulses to UP2,S
• Test loop at -U0 , 10 consecutive impulses to -UP2,S
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Type Test LCC (2)
• LCC electrical test sequence
– Superimposed lightning impulse withstand test (if required)
• Test loop at U0 , 10 consecutive impulses to –UP1
• Test loop at -U0 , 10 consecutive impulses to UP1
– Subsequent DC test
• 2 h at –UT , no heating
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Type Test – VSC and LCC
• Simplified principle
© ABB Group January 27, 2012 | Slide 42
VSC
LCC
High Voltage test Superimposed surges
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Type Test
• Other tests
– After both VSC and LCC test sequences, test of outer
protection for joints intended for burial on land shall be
performed as specified in IEC 62067 § 12.4
– Cables with longitudinally applied metal tape or foil bonded
to the oversheath shall be subjected to tests specified in IEC
62067
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Type Test
• Return cable test sequence
– Mechanical preconditioning
– Thermo-mechanical preconditioning
• 24 daily cycles, i.e. “24 hours” Load Cycles without any requirement on
∆∆∆∆Tmax
• No voltage applied
– AC voltage test at
• 1.15 x URC,AC at power frequency for 30 minutes
• Ambient temperature
– Lightning impulse withstand test at relevant test voltages
– Cable with integrated return conductor
• For such a design, the return path function should be tested together
with the power transmission cable in an integrated test program
• The test program shall be agreed between customer and supplier
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Example: Type Test Sequence VSC, U0 = 300 kV
-600
-400
-200
0
200
400
600
0 120 240 360 480 600 720
Tes
t Vol
tage
(kV
)
Elapsed time (hours)
VSC Type Test schedule
1/ “24 h” Load Cycles -UT
• -1.85 x UO 12 load cycles
• 8 h heating / 16 h cooling(applied current leads to design temperature)
• Tmax & ∆Tmax
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-600
-400
-200
0
200
400
600
0 120 240 360 480 600 720
Tes
t Vol
tage
(kV
)
Elapsed time (hours)
VSC Type Test schedule
Example: Type Test Sequence VSC, U0 = 300 kV
2/ “24 h” Load Cycles +UT
• +1.85 x UO 12 load cycles
• 8 h heating / 16 h cooling(applied current leads to design temperature)
• Tmax & ∆Tmax
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Example: Type Test Sequence VSC, U0 = 300 kV
-600
-400
-200
0
200
400
600
0 120 240 360 480 600 720
Tes
t Vol
tage
(kV
)
Elapsed time (hours)
VSC Type Test schedule
3/ “48 h” Load Cycles +UT
• + 1.85 x UO 3 load cycles
• 24 h heating / 24 h cooling(applied current leads to design temperature)
• Tmax & ∆Tmax
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Example: Type Test Sequence VSC, U0 = 300 kV
4/ Switching Impulse Withstand Test
• Maximum temperature (applied current leads to design temperature)
• Tmax & ∆Tmax and U0 for 10 h minimum before testing
• Test object under +U0
• 10 consecutive shots, same polarity as DC
• Switching Impulse voltage : +UP2,S
• Waveform in agreement with IEC 60230
• 10 consecutive shots, opposite polarity to DC
• Switching Impulse level : -UP2,O
• Waveform in agreement with IEC 60230
•Test object under -U0
• 10 consecutive shots, same polarity as DC
• Switching Impulse voltage : -UP2,S
• Waveform in agreement with IEC 60230
• 10 consecutive shots, opposite polarity to DC
• Switching Impulse voltage : +UP2,O
• Waveform in agreement with IEC 60230
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Example: Type Test Sequence VSC, U0 = 300 kV
5/ Lightning Impulse Test (if required)
• Maximum temperature (applied current leads to design temperature)
• Tmax & ∆Tmax and U0 level for 10 h minimum before testing
• Test object under +U0
• 10 consecutive shots, opposite polarity to DC
• Lightning Impulse voltage : - UP1
• Waveform in agreement with IEC 60230
•Test object under -U0
• 10 consecutive shots, opposite polarity to DC
• Lightning Impulse voltage : +UP1
• Waveform in agreement with IEC 60230
6/ Conclusion : Subsequent DC Test
• -1.85 x UO for 2 hours – No heating
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Routine Tests (1)
• Routine test on transmission cables
– Each delivery length shall be submitted to UT = 1.85 x U0 for 1 hour
– AC voltage testing could be considered provided the insulation system
and the cable design allow AC testing
– If AC testing is impractical due to the cable length, the voltage level, the
frequency, the voltage level, frequency and time of application can be
adjusted to perform the test (agreement between client and supplier)
• Routine tests on cable accessories
– The experience of using DC voltages for routine testing of accessories for
DC extruded cables is limited, and the efficiency not proven so far
– Testing with AC could be a relevant alternative, provided that the
insulation system and the design allow AC testing
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Routine Tests (2)
• Routine tests on cable accessories
– Tests on prefabricated joints and terminations
• DC test voltage applied to the main insulation of each individual
prefabricated accessory shall be performed. Same requirement as for the
cable alone (UT = 1.85 x U0 for 1 hour )
• AC voltage test, if applicable
• PD measurement, if applicable
– Test on factory joints of submarine cables
• DC test (UT = 1.85 x U0 for 1 hour )
• AC voltage test, if applicable
• PD measurement, if applicable
• X-ray inspection
– Repair joint for submarine cables
• Same procedure as for prefabricated joints and terminations
• Agreement between client and supplier if the joint is not built of any pre-
fabricated component
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Routine Tests (3)
• Return cables or conductors
– Each delivery length shall be submitted to a voltage test
– AC testing is preferred
– Voltage level and time of application shall be agreed
between supplier and client
– If the AC test is rendered impractical (long manufacturing
lengths, high voltage levels), a suitable DC voltage shall be
applied instead (agreement between client and supplier)
• DC test voltage ≥ 2.5 x URC,DC or 25 kV
• Voltage applied for 1 hour
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Sample Tests (1)
• Sample tests on transmission cables (refer to IEC 62067)
– For materials not mentioned in IEC 60840 / 62067, the test program shall
be agreed between manufacturer and customer
– Frequency of test: in agreement with IEC 62067
– Tests• Conductor examination
• Electrical resistance of conductor
• Capacitance
• Thickness of insulation and non-metallic sheath
• Thickness of metallic sheath
• Diameters, if required
• Density of HDPE insulation, if required
• Impulse voltage test
• Water penetration test, if applicable
• Tests on components of cables with longitudinally applied metal tape or foil, bonded to the oversheath, if applicable
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Sample Tests (2)
• Sample tests on factory joints for submarine cables (1)
– For a submarine cable system, the sample tests shall be performed on
one factory conductor joint only, prior to starting manufacture of the
joints
– A sample of at least 10 m of cable and a factory joint shall be prepared
for the test
– Tensile test
• The tensile test of the conductor joint shall be performed according to
manufacturer specification
• The tensile force applied to the conductor shall not be lower than the design
value
• Test omitted if the factory joint is type tested under the contract
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Sample Tests (3)
• Sample tests on factory joints for submarine cables (2)
– PD measurement and AC voltage
• Test performed if applicable to the insulation system
• Performed after restoring the outer semiconductive layer and the metallic
ground conductor or outer sheath
• PD measurement and AC voltage test shall be performed according to the
manufacturer quality assurance procedures
– Impulse voltage test
– Hot set test for insulation where applicable
• Refer to IEC 62067 §10.9
– Pass criteria
• If a factory joint fails in any of the listed items above, 2 additional joints shall
be tested successfully
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Sample Tests (4)
• Sample tests on repair joints and terminations
– Sample tests are not applicable for repair joints and terminations for
submarine cable systems
– They shall be routine tested (§ 5.2.1 and 5.2.3 of the present technical
brochure)
• Sample tests on field moulded joints
– These joints may be used for land cable systems
– They cannot be routine tested and the sample test sequence as
requested in IEC 62067 is recommended
– Frequency of tests and procedure as described in IEC 62067
– Same tests as for factory joints of submarine cables of the present
technical brochure (§ 5.2.2)
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After installation Tests
• High voltage test
– The installed cable system shall be subjected to a negative DC voltage of
UT = 1.45 x U0 for 1 hour
– The return cable system shall be subjected to a negative DC voltage that
was agreed between supplier and client for 1 hour
– Negative polarity is applied regardless the polarity of the pole
• Test on polymeric sheath
– Used to be applied for underground cables
– Shall be performed according to IEC 60229, if appropriate
• TDR measurement (for engineering information)
– Fingerprint of the wave propagation of the cable
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