Presention Details (9)

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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

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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.

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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

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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)

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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

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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.

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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

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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

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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

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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.

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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

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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

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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.

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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

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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

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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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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

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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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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

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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

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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

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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


At least 24 h of natural cooling

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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


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


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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

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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

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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.

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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

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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

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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

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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

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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

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-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

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-600

-400

-200

0

200

400

600

0 40 80 120 160 200 240 280 320 360

Test

Vol

tage

(kV)

Elapsed Time (days)


Load Cycles :

- 1.45 x UO 40 cycles



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-400

-200

0

200

400

600

0 40 80 120 160 200 240 280 320 360

Test

Vol

tage

(kV)

Elapsed Time (days)



High Load :

+ 1.45 x UO 40 days

Continuous Heating(applied current leads to design temperature)

Tmax & Tmax

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-600

-400

-200

0

200

400

600

0 40 80 120 160 200 240 280 320 360

Test

Vol

tage

(kV)

Elapsed Time (days)


High Load :

- 1.45 x UO 40 days

Continuous Heating(applied current leads to design temperature)

Tmax & Tmax

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-400

-200

0

200

400

600

0 40 80 120 160 200 240 280 320 360

Test

Vol

tage

(kV)

Elapsed Time (days)


Zero Load :

- 1.45 x UO 120 days

No Heating

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-600

-400

-200

0

200

400

600

0 40 80 120 160 200 240 280 320 360

Test

Vol

tage

(kV)

Elapsed Time (days)


Load Cycles :

+ 1.45 x UO 40 cycles



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-600

-400

-200

0

200

400

600

0 40 80 120 160 200 240 280 320 360

Test

Vol

tage

(kV)

Elapsed Time (days)


Load Cycles :

- 1.45 x UO 40 cycles



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-600

-400

-200

0

200

400

600

0 40 80 120 160 200 240 280 320 360

Test

Vol

tage

(kV)

Elapsed Time (days)


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)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.

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

Test

Vol

tage

(kV)

Elapsed time (hours)

VSC Type Test schedule

1/ 24 h Load Cycles -UT -1.85 x UO 12 load cycles


Tmax & Tmax

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-600

-400

-200

0

200

400

600

0 120 240 360 480 600 720

Test

Vol

tage

(kV)




2/ 24 h Load Cycles +UT +1.85 x UO 12 load cycles


Tmax & Tmax

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-400

-200

0

200

400

600

0 120 240 360 480 600 720

Test

Vol

tage

(kV)



3/ 48 h Load Cycles +UT + 1.85 x UO 3 load cycles


Tmax & Tmax

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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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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 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

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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

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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

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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

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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

Cigr 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

Cigr 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)

Cigr 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

Cigr 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

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Presention Details (9)