Qualification procedure of HVDC cables

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



1



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)

2



Content

• Introduction

• Cable types






3



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..

4



Content

• Introduction

• Cable types






5



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

?

6




Example:

• Lightning impulse

– Will the cable system experience it?

– Test it / qualify it?

7




Example:

• Temperature

– Low temperature for MI cable

– High temperature for Extruded DC cable

8




• 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

9




• High temperature for Extruded DC cable

– Test at high environmental temperature

Illustrative example…

10



Content

• Introduction

• Cable types






11



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




• 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.

13




• 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.”

14




• 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.”

15



Content

• Introduction

• Cable types






16



Mechanical testing (Electra 171)

• Recommendations for Mechanical Tests on

Sub-marine Cables

17




• Electrical qualification tests adress the entire in-service life

time of the cable

• Mechanical qualification tests adress the laying and/or

recovery operation

18




• 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

19




• Tensile Bending Test

• Tensile Test

2 ×T

Pulley

Rotating drum

Joint

Cable heads

20




• Calculation of test forces– related to laying and recovery forces

< 500 m

≥ 500 m

21



Content

• Introduction

• Cable types






22



DC paper cables (Electra 189)

• Recommendations for Tests of Power

Transmission DC Cables for a Rated Voltage up

to 800 kV

23




• 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)

24




• Type Test, remember �

– Example below:

MI cables

25




• 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

26




• 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

27




• After Laying Test– Negative voltage of 1.8 U0 during 15 minutes

28



Content

• Introduction

• Cable types






29



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

30



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

31



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)

32



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

33



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.

34



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

35



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

36



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

37



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.

38



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

39




• 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

40




• 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.

41




• 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

42



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

43



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

44



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

45



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

46



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

47



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

48



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

49



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

50



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

51



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

52



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

53



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.

54




• 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

55




• 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

56




• 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

57




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

58




• 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

59



-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

60




-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)


Load Cycles :

• - 1.45 x UO 40 cycles




61



-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)



High Load :

• + 1.45 x UO 40 days

• Continuous Heating


• Tmax & ∆Tmax

62




-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)


High Load :

• - 1.45 x UO 40 days

• Continuous Heating


• Tmax & ∆Tmax

63




-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)


Zero Load :

• - 1.45 x UO 120 days

• No Heating

64




-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)


Load Cycles :

• + 1.45 x UO 40 cycles




65




-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)


Load Cycles :

• - 1.45 x UO 40 cycles




66




-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)


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

67



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.

68



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

69



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


– 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


• 2 h at –UT , no heating

74



Type Test LCC (1)

• LCC electrical test sequence

– 8 x ”24 hours” Load Cycles at -UT


– 8 x ”24 hours” Load Cycles with polarity reversals at UTP1


– 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

75



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


• 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

80



-600

-400

-200

0

200

400

600

0 120 240 360 480 600 720

Tes

t Vol

tage

(kV

)




2/ “24 h” Load Cycles +UT

• +1.85 x UO 12 load cycles


• Tmax & ∆Tmax

81




-600

-400

-200

0

200

400

600

0 120 240 360 480 600 720

Tes

t 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


•Test object under -U0

• 10 consecutive shots, same polarity as DC

• Switching Impulse voltage : -UP2,S



• Switching Impulse voltage : +UP2,O


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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


• Lightning Impulse voltage : - UP1


•Test object under -U0


• Lightning Impulse voltage : +UP1


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

85



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

87



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

90



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)

91



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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Qualification procedure of HVDC cables

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