Page 1Cigr SCB1
RECOMMENDATIONS FOR TESTING DC EXTRUDED CABLE SYSTEMS FOR POWER TRANSMISSION AT A RATED
VOLTAGE UP TO 500 kV
TUTORIAL B1.32 TB 496
4 th Interactive Workshop on HV Cables, System and AccessoriesMumbai 24 - 25 th February 2015
Page 2Cigr SCB1
Copyright
DISCLAIMEROwnership of a CIGRE publication, whether in paper form or on electronic support only infers right of use
for personal purposes. Are prohibited, except if explicitly agreed by CIGRE, total or partial reproduction of the publication for use other than personal and transfer to a third party; hence circulation on any intranet or other company network is forbidden.
Page 3Cigr SCB1
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 Comparison with other recommendations / standards
Page 4Cigr SCB1
WG Scope of work (1)
Backgroundo TB 219 issued in February 2003 addresses HVDC extruded cable
systems up to 250 kVo Due to commercially available HVDC systems above 250 kV an
update to 500 kV was necessary General scope
o Prepare a recommendation for testing DC extruded cable systems up to 500 kV
o Step 1: review TB 219 principles with respect to eventual inadequacy for DC voltages beyond 250 kV
o Step 2: develop a new recommendation (new TB)
Working Group duration: 3 years (2009-2011)
Page 5Cigr SCB1
WG Scope of work (2)
Scope of worko Survey of laboratory and operational experienceo Consider extrapolation of TB 219 principles to 500 kVo Consider both submarine and land applications and aspects related
to testing of long lengthso Electrical, thermal and mechanical aspectso Refer to appropriate standards and recommendationso 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
Page 6Cigr SCB1
Survey of laboratory and operational experience
At the time of preparing this recommendation o Laboratory experience at voltages up to and including 500 kV o Operating experience limited to 200 kV o Commercial Contracts awarded at a voltage level up to 320 kV o A further increase in voltage level is to be expected and this
recommendation will therefore cover voltages up to 500 kV.
o 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.
Page 7Cigr SCB1
WG B1.32 Members
COUNTRY NAMECANADA 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 Bjrn Sanden (Convenor)
SWEDEN Marc Jeroense
SWITZERLAND Detlef Wald
UK Roman SvomaCORRESPONDING MEMBERS:
AUSTRALIA Joska Ferencz
ITALY Luigi Colla
US Steve Eckroad
Page 8Cigr SCB1
Revisions with respect to TB 219 (1)
Discussion on technical basiso Determination of voltage factors at V > 250 kV ?o Inverse power law and n values at V > 250 kV ?o Time constants at V > 250 kV, resistivity of insulating materials ?o Examination of TB 303 outcome and relevance for HVDC extruded
o WG consensus: TB 219 principles shall cover higher voltage levels until some discrepancies are displayed by operational and/or lab experience
Page 9Cigr SCB1
Revisions with respect to TB 219 (2)
Main changes:o Voltage range extended to 500 kVo General text update to take into account latest revisions of IEC
60840/62067 wordingo Range of approval of both prequalification and type tests have been
revisedo Load cycle blocks of PQ test refers to number of cycles instead of
number of dayso 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
o Recommendations for routine / sample tests on cable accessories have been included
Page 10Cigr SCB1
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. o 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
o 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.
Page 11Cigr SCB1
Overview of proposed tests (1)
Where applicable, all definitions are in line with IEC 60840 and IEC 62067
Development Tests o Tests made during the development of the cable systemo 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
Page 12Cigr SCB1
Overview of proposed tests (2)
Prequalification tests (PQ tests)o 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
Page 13Cigr SCB1
Overview of proposed tests (3)
Type testso 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.
Page 14Cigr SCB1
Overview of proposed tests (4)
Routine testso Made by the manufacturer on manufactured component, cable
length or accessory, to check that it meets the specified requirements
Sample testso 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 testso Made to demonstrate the integrity of the cable system as installed
Page 15Cigr SCB1
Technical basis (1)
Voltage factorso Based on available V-t characteristics for DC operationo Inverse power law provided a conservative basis for the worko 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
nttK
1
01 =
t0 design life t1 test duration
Inverse power law
Page 16Cigr SCB1
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
Page 17Cigr SCB1
Technical basis (3)
Time constantso Determine the duration of test sequences (steady state aimed at)o Resistivity of insulation materials vs. E and To Higher resistivity materials may be developed and a review of test
block durations may be required in the future
Temperature(C)
(F/m)
(.m)
Time for stability, 10 (hours)
20 2x10-11
Page 18Cigr SCB1
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
Page 19Cigr SCB1
DC tests voltages, examples
Rated voltage
Type testRoutine tests
PQ test: Load cycle testType test: Polarity reversalsAfter 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
Page 20Cigr SCB1
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 negativeswitching impulse
kV
- UP2,S- U0
kV
t
- U0
UP2,Ot
LCC or VSC, opposite polarity positive switching impulse
Lightning impulse (LI)o UP1 = 1.15 x max. absolute value
of the design LI voltage when LI has opposite polarity to DC
Switching Impulse (SI)o UP2,S = 1.15 x max. absolute
value of the design SI voltage when SI has same polarity as DC
o UP2,O = 1.15 x max. absolute value of the design SI voltage when SI has opposite polarity as DC
Page 21Cigr SCB1
Thermal parameters
Tcond,maxo Maximum temperature the cable conductor is designed to operateo Stated by the supplier
Tmaxo Maximum temperature drop over the cable insulation in steady
state at which the cable is designed to operateo The semiconducting screens are not includedo This value is stated and calculated by the suppliero The supplier shall correlate this design value with data measured
during testing Ambient temperature
o (20 15) C
Page 22Cigr SCB1
Thermal conditions for tests (1)
Load Cycles (LC)o Consist of a heating period followed by a cooling periodo 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 coolingo 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
Page 23Cigr SCB1
Thermal conditions for tests (2)
High Load (HL)o Consists of a continuous heating periodo Within the first 8 hours, the following conditions shall be achieved
Tcond Tcond,max T Tmax
o 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)o No heating applied
Prior to impulse testso The following conditions shall be met for at least 10 h before impulses
Tcond Tcond,max T Tmax
Page 24Cigr SCB1
Specific test conditions (1)
Polarity reversal test (PR) 24 hours load cycleso LC sequence and voltage as described previouslyo Starting with positive polarityo 3 polarity reversals evenly distributed shall be performed during a
24 hours load cycle (therefore at least 8 h between reversals) o One reversal shall coincide with the cessation of heating currento 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 testso 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
o This was selected to reflect the electric dynamics of extruded insulations under HVDC
Page 25Cigr SCB1
Specific test conditions (2)
Check on insulation thickness of cable (IEC 60811-1-1)o Prior to all electrical testso Consistency with IEC 60840 and IEC 62067 standards
Return cable voltage definitionso 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
o URC,DC Maximum DC voltage in normal operation
Page 26Cigr SCB1
Prequalification Test
The prequalification test is intended to indicate the long-term performance of the complete cable system and shouldnormally 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. o A substantial change is defined as that which might adversely
affect the performance of the cable system. o The supplier shall provide a detailed case including test evidence
if modifications are introduced, which are claimed not to constitute a substantial change.
Page 27Cigr SCB1
Prequalification Test
Range of approvalo The rated voltage U0 is not more than 10% higher than that of the tested cable
system.o 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.o 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.
o The maximum conductor temperature Tcond,max is less than or equal to that of the tested system.
o The maximum temperature drop across the insulation layer Tmax (excluding the semiconducting screens) is less than or equal to that of the tested system.
o 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.
o An unarmoured cable prequalified according to this recommendation prequalifies an armoured cable and vice versa
Page 28Cigr SCB1
Prequalification Test
Comments to the range of approvalo Cigr 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
o 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
o The use of a large conductor cross-section is recommended to cover thermo-mechanical aspects
o PQ tests performed according to TB 219 are valido 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
Page 29Cigr SCB1
Prequalification Test
Generalo At least 100 m of cable including at least one complete accessory of
each type should be testedo Where appropriate mechanical preconditioning may be considered
before starting the PQ testo Minimum duration of voltage test is 360 days
Test arrangemento Cable and accessories shall be assembled according to
manufacturer's instructionso The test loop should reflect the installation conditions
Sequence of testso Long duration voltage testo Superimposed impulse voltage testo Examination
Page 30Cigr SCB1
Prequalification Test
LC LC LC+PR HL HL ZL LC LC LC+PR S/IMP
Number of cycles or days
30cycles
30cycles
20cycles
40days
40days
120days
30cycles
30cycles
20cycles Not applicable
Test Voltage+ - + - - + -
UP2,O = 1.2 x U0UP1 = 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
40cycles
40cycles
40days
40days
120days
40cycles
40cycles Not applicable
Test Voltage+ - + - - + - UP2,O = 1.2 x U0
UP1 = 2.1 x U0*UTP1 UTP1 UTP1 UTP1 UTP1 UTP1 UTP1
Page 31Cigr SCB1
Prequalification Test
Impulse test levelso UP2,O = 1.2 x U0o UP1 = 2.1 x U0 (agreement between customer and supplier)o 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 - Interruptionso 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
Page 32Cigr SCB1
-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Test
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
Page 33Cigr SCB1
Example: Prequalification Test VSC, U0 = 320 kV
-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Test
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
Page 34Cigr SCB1
-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Test
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
Page 35Cigr SCB1
Example: Prequalification Test VSC, U0 = 320 kV
-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Test
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
Page 36Cigr SCB1
Example: Prequalification Test VSC, U0 = 320 kV
-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Test
Vol
tage
(kV)
Elapsed Time (days)
VSC prequalification test schedule
Zero Load :
- 1.45 x UO 120 days
No Heating
Page 37Cigr SCB1
Example: Prequalification Test VSC, U0 = 320 kV
-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Test
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
Page 38Cigr SCB1
Example: Prequalification Test VSC, U0 = 320 kV
-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Test
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
Page 39Cigr SCB1
Example: Prequalification Test VSC, U0 = 320 kV
-600
-400
-200
0
200
400
600
0 40 80 120 160 200 240 280 320 360
Test
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
Page 40Cigr SCB1
Type Test
Range of approval (1)o The actual designs, materials, manufacturing processes and service
conditions for the cable system are in all essential aspects equal.o 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.o The mechanical stresses to be applied during preconditioning are less than
or equal to those of the tested cable system.o The service maximum conductor temperature Tcond,max is less than or equal
to that of the tested cable system.o 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.
o The actual conductor cross-section is not larger than that of the tested cable system.
Page 41Cigr SCB1
Type Test
Range of approval (2)o 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.
o 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.
o A cable system qualified according to this recommendation for LCC is also qualified for VSC provided the switching impulse withstand tests at UP2,Svoltage 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
Page 42Cigr SCB1
Type Test
Comments to the range of approvalo 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
o 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
o 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
o Type tests successfully performed according to TB 219 are valid
Page 43Cigr SCB1
Type Test
Test objectso All components of the cable system shall be subjected to type testo Different parts of a system could be in different loops
Non-electrical type testso The cable system shall be applied to non-electrical type testing as
specified in IEC 62067 Ed. 2o Land cable systems including water blocking featurs shall be
subjected to a water penetration test as specified in IEC 62067 Ed. 2
o Submarine cable systems shall be subjected to a water integrity test as specified in Electra 189, April 2000
o Cables with metallic earthing connections through plastic sheath shall be subjected to the relevant test in Electra 189, April 2000
Page 44Cigr SCB1
Type Test: Electrical Type Test
Submarine cables Tensile bend test
Electra 171 [7]
Submarine cables Tensile bend testElectra 171 [13]
Land cables Bend test
IEC 62067 [4]
LCC Load Cycling( 4.4.2.2)
VSC Load Cycling( 4.4.2.3)
LCC Switching( 4.4.3.2)
VSC Switching( 4.4.3.3)
Lightning( 4.4.3.4)
Subsequent DC( 4.4.3.5)
Mechanical preconditioningo Appropriate for land or submarine
cable applicationo Aim: subject the test object to the
maximum mechanical stress experienced during handling, installation and recovery
o Land cable systems: IEC 62067 Ed. 2o Submarine cable systems: Electra 171
Electrical tests sequenceo Load cycles testso Superimposed impulse testso Subsequent DC testo Test of outer protection for jointso Examination
Page 45Cigr SCB1
Type Test
Note on success criteria - Interruptionso 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 blockso Minimum rest periods of 24 h are recommended between test
blocks of different polaritieso No voltage, heating applied (at the discretion of the manufacturer)o The goal is to relax the electrical / eventually mechanical stresseso Rest periods do not apply to individual polarity reversals in the
polarity reversal blocks
Page 46Cigr SCB1
Type Test VSC
VSC electrical test sequenceo 12 x 24 hours Load Cycles at -UTo 12 x 24 hours Load Cycles at +UTo 3 x 48 hours Load Cycles at +UTo 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
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
o Subsequent DC test 2 h at UT , no heating
Page 47Cigr SCB1
Type Test LCC (1)
LCC electrical test sequenceo 8 x 24 hours Load Cycles at -UTo 8 x 24 hours Load Cycles at +UTo 8 x 24 hours Load Cycles with polarity reversals at UTP1o 3 x 48 hours Load Cycles at +UTo 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
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
Page 48Cigr SCB1
Type Test LCC (2)
LCC electrical test sequenceo 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
o Subsequent DC test 2 h at UT , no heating
Page 49Cigr SCB1
Type Test
Other testso 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
o Cables with longitudinally applied metal tape or foil bonded to the oversheath shall be subjected to tests specified in IEC 62067
Page 50Cigr SCB1
Type Test
Return cable test sequenceo Mechanical preconditioningo Thermo-mechanical preconditioning
24 daily cycles, i.e. 24 hours Load Cycles without any requirement on Tmax
No voltage appliedo AC voltage test at
1.15 x URC,AC at power frequency for 30 minutes Ambient temperature
o Lightning impulse withstand test at relevant test voltageso 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
Page 51Cigr SCB1
Example: Type Test Sequence VSC, U0 = 300 kV
-600
-400
-200
0
200
400
600
0 120 240 360 480 600 720
Test
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
Page 52Cigr SCB1
-600
-400
-200
0
200
400
600
0 120 240 360 480 600 720
Test
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
Page 53Cigr SCB1
Example: Type Test Sequence VSC, U0 = 300 kV
-600
-400
-200
0
200
400
600
0 120 240 360 480 600 720
Test
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
Page 54Cigr SCB1
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
Page 55Cigr SCB1
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
Page 56Cigr SCB1
Routine Tests (1)
Routine test on transmission cableso Each delivery length shall be submitted to UT = 1.85 x U0 for 1 houro AC voltage testing could be considered provided the insulation
system and the cable design allow AC testingo 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 accessorieso The experience of using DC voltages for routine testing of
accessories for DC extruded cables is limited, and the efficiency not proven so far
o Testing with AC could be a relevant alternative, provided that the insulation system and the design allow AC testing
Page 57Cigr SCB1
Routine Tests (2)
Routine tests on cable accessorieso 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
o 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
o 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
Page 58Cigr SCB1
Routine Tests (3)
Return cables or conductorso Each delivery length shall be submitted to a voltage testo AC testing is preferredo Voltage level and time of application shall be agreed between
supplier and cliento 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
Page 59Cigr SCB1
Sample Tests (1)
Sample tests on transmission cables (refer to IEC 62067)o For materials not mentioned in IEC 60840 / 62067, the test program
shall be agreed between manufacturer and customero Frequency of test: in agreement with IEC 62067o 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
Page 60Cigr SCB1
Sample Tests (2)
Sample tests on factory joints for submarine cables (1)o For a submarine cable system, the sample tests shall be performed
on one factory conductor joint only, prior to starting manufacture of the joints
o A sample of at least 10 m of cable and a factory joint shall be prepared for the test
o 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
Page 61Cigr SCB1
Sample Tests (3)
Sample tests on factory joints for submarine cables (2)o 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 procedureso Impulse voltage testo Hot set test for insulation where applicable
Refer to IEC 62067 10.9o Pass criteria
If a factory joint fails in any of the listed items above, 2 additional joints shall be tested successfully
Page 62Cigr SCB1
Sample Tests (4)
Sample tests on repair joints and terminationso Sample tests are not applicable for repair joints and terminations for
submarine cable systemso They shall be routine tested ( 5.2.1 and 5.2.3 of the present
technical brochure) Sample tests on field moulded joints
o These joints may be used for land cable systemso They cannot be routine tested and the sample test sequence as
requested in IEC 62067 is recommendedo Frequency of tests and procedure as described in IEC 62067o Same tests as for factory joints of submarine cables of the present
technical brochure ( 5.2.2)
Page 63Cigr SCB1
After installation Tests
High voltage testo The installed cable system shall be subjected to a negative DC
voltage of UT = 1.45 x U0 for 1 houro The return cable system shall be subjected to a negative DC voltage
that was agreed between supplier and client for 1 houro Negative polarity is applied regardless the polarity of the pole
Test on polymeric sheatho Used to be applied for underground cableso Shall be performed according to IEC 60229, if appropriate
TDR measurement (for engineering information)o Fingerprint of the wave propagation of the cable
Page 64Cigr SCB1
Recommendations for testing DC Extruded cable systems for power transmission at a rated voltage up to 500 kVCopyrightContentWG Scope of work (1)WG Scope of work (2)Survey of laboratory and operational experienceWG B1.32 MembersRevisions with respect to TB 219 (1)Revisions with respect to TB 219 (2)Scope of the recommendationOverview of proposed tests (1)Overview of proposed tests (2)Overview of proposed tests (3)Overview of proposed tests (4)Technical basis (1)Technical basis (2)Technical basis (3)Test objectsDC tests voltages, examplesImpulse tests voltagesThermal parametersThermal conditions for tests (1)Thermal conditions for tests (2)Specific test conditions (1)Specific test conditions (2)Prequalification TestPrequalification TestPrequalification TestPrequalification TestPrequalification TestPrequalification TestExample: Prequalification Test VSC, U0 = 320 kVExample: Prequalification Test VSC, U0 = 320 kVExample: Prequalification Test VSC, U0 = 320 kVExample: Prequalification Test VSC, U0 = 320 kVExample: Prequalification Test VSC, U0 = 320 kVExample: Prequalification Test VSC, U0 = 320 kVExample: Prequalification Test VSC, U0 = 320 kVExample: Prequalification Test VSC, U0 = 320 kVType TestType TestType TestType TestType Test: Electrical Type TestType TestType Test VSCType Test LCC (1)Type Test LCC (2)Type TestType TestExample: Type Test Sequence VSC, U0 = 300 kV Example: Type Test Sequence VSC, U0 = 300 kV Example: Type Test Sequence VSC, U0 = 300 kV Example: Type Test Sequence VSC, U0 = 300 kV Example: Type Test Sequence VSC, U0 = 300 kV Routine Tests (1)Routine Tests (2)Routine Tests (3)Sample Tests (1)Sample Tests (2)Sample Tests (3)Sample Tests (4)After installation TestsSlide Number 64