A.3.6 8th International Conference on Insulated Power

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A.3.6
8th International Conference on Insulated Power Cables
A.3.6
DEVELOPMENT, QUALIFICATION AND EXPERIENCES WITH 500 KV XLPE CABLE
SYSTEMS
Johannes KAUMANNS, Andreas WEINLEIN, Gero SCHRÖDER, Südkabel GmbH, Volker STROOT
Südkabel GmbH Mannheim (Germany)
[email protected], [email protected], [email protected],
[email protected]
ABSTRACT
10 years after the first installation of a 550kV XLPE cable
system in China, an advanced system has been
developed and qualified. The XLPE cable system consists
of a cable with a conductor cross section of 2500mm²,
one piece silicone rubber joint, plug-in GIS termination,
plug-in dry type outdoor termination and compound filled
outdoor termination with composite insulator.
Both, the type test and pre-qualification test have been
carried out according the IEC62067 requirements
Additionally, tests with increased AC and impulse levels
has been carried out.
The new cable system has been installed successfully at
projects in Sudan, China, Columbia, Russia and other
locations.
These experiences demonstrate that 550kV XLPE cable
systems are state-of-the-art technology.
KEYWORDS
500 kV XLPE cable system, one piece silicone rubber
joint, PD monitoring system, plug-in compact sealing end,
PQ test
INTRODUCTION
10 years after the first installation of a 550 kV XLPE cable
system in China in the year 2000 [1], an advanced system
has been developed and qualified. The above mentioned
first 550kV systems were primarily designed for short
cable connections inside power plants, but with increasing
need for longer cable systems an advanced system
became necessary for higher transmission loads and
longer cable length for the 500kV voltage level as
described in [2].
installation conditions of the cable (buried installation, pipe
installation and clamped installation). Additional PD tests
has been carried out during the full test duration and highlevel impulse tests with 1675 kV BIL demonstrate the
dielectric performance of the cable. All qualification tests
have been carried out at the independent testing institute
IPH / CESI in Berlin (Germany).
Further tests with a compact plug-in sealing end installed
inside the oil immersed transformer cable connection
enclosure of a 500 kV transformer were carried out in
2010 in a factory installation Powertech Transformers
(Pty) Ltd Pretoria (South Africa). Additional dielectric tests
with increased testing parameters (AC and impulse) have
been carried out with GIS-terminations at the IEH testing
institute in Karlsruhe (Germany)
The new cable system has been installed successfully
and went into operation around the world, in North Africa,
China, Colombia, Russia (at voltage level 550 kV) and
other locations demonstrating the progress and
experiences in this voltage level under different
installation conditions.
These experiences show that 500 kV XLPE cable
systems are state-of-the-art XLPE cable technology.
ADVANCED 550 KV XLPE SYSTEM
The qualified XLPE cable show a six segmental copper
conductor with a cross section of 2500 mm². The EHVgrade XLPE insulation material shows a thickness of
27mm and was applied by triplex extrusion process
together with both semicon layers in a horizontal extrusion
line. Figure 1 shows details of the cable design:
The new EHV cable system shows an XLPE isolated
cable with a conductor cross section of 2500mm² and
prefabricated accessories of the newest generation: One
piece silicone rubber joints, compact SF6-plug-in sealing
ends, plug-in dry type outdoor sealing ends and
compound-filled outdoor sealing ends with composite
insulators.
The main parameters of the pre-qualified cable system
are:
•
•
550 kV
voltage level Um:
conductor cross section (copper / segmental):
2
2500 mm
• XLPE insulation thickness of cable:
27 mm
The type test has been carried out according the IEC
62067 [5] requirements for the Umax = 550 kV level. The
one year prequalification (PQ) test covers different
1
conductor
copper, RMS, 6 segments
2
conductor
screen
Conductive XLPE-compound
3
insulation
XLPE
4
insulation
screen
Conductive XLPE-compound
5
bedding
swelling tape, semi-conducting
6
wire
screen
copper screen wires
7
bedding
semi-conducting swelling tape
8
bedding
fabric tape, semi-conducting
9
metallic
sheath
10
outer
sheath
Co-polymer-laminated aluminium
foil
HDPE,
two outer layers conductive and
flame-retardant
Fig. 1: Cable design for type and PQ test
The copper wire screen design is longitudinally watertight
and the laminated aluminium foil design delivers a save
radial water protection to the cable under all installation
conditions. A strong HDPE outer jacket, which is fix
bonded to the aluminium foil, provides the mechanical
protection of the cable.
The well known compact sealing end of type EHSVS 550
(type F) was taken as SF6 termination. The outside
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A.3.6
8th International Conference on Insulated Power Cables
dimensions are according to the actual IEC 62271-209
standard. This plug-in termination provides an absolute
dry solution without any liquid or gaseous contents.
If taking into account the needed space below the GIS
switchgear during the installation and lifting of the
termination during the installation work the cable
installation work can be done separately from GIS work.
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from glass fiber reinforced epoxy resin provides a good
mechanical protection for the joint main insulation body.
A top cover allows an easy installation of a cross bonding
cable if needed.
Fig. 5: 500 kV one piece joint
TYPE AND PQ-TEST
The type test set-up consists of the above mentioned
XLPE cable, one–piece silicone-rubber joint, compact
OSE and compound filled OSE. (See picture below)
Fig. 2: 500 kV compact SF6 sealing end
Two type of outdoor sealing ends have been type tested:
The well known SF6 filled type with plug-in connection [3]
and a compound filled design with prefabricated stress
cone (Fig. 3, left). The gas filled type can be pre-mounted
and pre tested in the factory and allows a shortened
installation time on-side (Fig. 4).
On the other hand the compound filled type shows an SF6
free solution. The heart piece of this type is the prefabricated stress cone made from silicone rubber.
Fig. 6: set-up of 500 kV type test
The compact SF6 sealing end of type EHSVS 550 (type
F) has been successfully type tested for the 550kV level
with the identical cable type since 2004 [3].
Fig. 7 (left): 500 kV type test – entire set-up
Fig. 8 (right): 500 kV type test – one piece joint
Fig. 3 (left): 500 kV compound filled OSE (stress cone)
Fig. 4 (right): 500 kV compact gas filled OSE
The testing parameters were chosen according the IEC
62067 standard (e.g. AC testing voltage 580kV, 20 load
cycles 95°C – 100°C, 1550kV BIL, 1175kV SIL). The tests
have been successfully carried out at IPH testing institute
in Berlin /Germany (CESI group).
The joint type is a one piece pre-molded joint. The main
insulation body is made from silicone rubber (SiR) with
integrated field control electrodes. An insulation section is
integrated in the outer conductive layer of the joint to
provide the screen separation when applied as cross
bonding joint.
The one year pre-qualification (PQ) set-up shows
additionally two compact SF6 sealing ends of type
EHSVS 550 and 100 m cable length of the above
mentioned cable. The cable and joint were installed buried
(see pictures below). Additionally, one section of the cable
has been installed in a pipe.
The outer corrosion protection is given by a coffin box
filled with an insulation compound. The coffin box made
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8th International Conference on Insulated Power Cables
A.3.6
Fig. 9: Set-up of 500 kV PQ test
Fig. 15: 500 kV PQ test – entire set-up at –20°C
The following figures show the a typical load cycle and the
measured temperatures on cable jacket, dummy
conductor, dummy jacket, load current, dummy current,
and the applied voltage.
Fig. 10 (left): 500 kV PQ test - cable laying
Fig. 11 (right): Back filling of pipe-laying installation
Fig. 12: Compact SF6 sealing ends of type EHSVS550
Fig. 13: One-piece SiR joint SEHDVCB550, buried
In order to monitor all relevant temperatures a total of 24
temperature sensors has been used (see next figure) at
both, the dummy circuit and distributed along the cable
circuit under test. The following figure gives the total
overview of the PQ test arrangement.
Empfäng$r an Schrank TS7
-A7
-A6
T01
LD1
ASA
RX30
T02
MD1
T1
T2
T3
T4
T09
MT1
ASA
RX30
MD3 MD5
T03 T04
15B4
T05
LD2
N
ASA
RX30
T2
T3
T4
17B0
T06
MD2
T1
T2
T3
T4
MD4 MD6
T07 T08
15B5
Dummy
T13
MT5
ASA
RX30
T2
T4
T1
T2
T3
T4
MT11 MT12
T19 T20
ASA
TX30
17B8
T14
MT6
T1
MT7
T15
ASA
RX30
MT4
T12
T3
17B4
-A8
T17 T18
MT9 MT10
T10
MT2
T1
MT3
T11
ASA
RX30
T1
T2
T3
T4
MT15
T23
MT8
T16
Endv$rschluss
EHFVC 550
fr$i
fr$i
17B1
11639/08
11641/08
TS7:MT2
T10
TS7:MT1
T09
Endv$rschluss
EHFVC 550
17BC
Hauptschl$if$
Hauptschl$if$
M2
11627/08
ASA
TX30
11628/08
ASA
T X30
ASA
TX30
17B0
11638/08
11640/08
T21 T22
MT13 MT14
M8
TS7:MT15
T23
th
Fig. 16: 156 load cycle T on buried cable
17BB
11610/08
11613/08
T20
TS7:MT12
17BE
TrafoSt$u$rung
T21
TS7:MT13
ASA
T X30
17BA
11470/08
11477/08
11469/08
11471/08
ASA
TX30
Trafo
17BC
TS7:MT1 1
T19
Muff$ VMSVS 550
ASA
TX30
17B9
11630/08
11631/08
ASA
TX30
17B8
11623/08
11625/08
TS7:MT10
T18
TS7:MT9
T17
M3
11634/08
11635/08
M6
ASA
T X30
17B2
TS7:MT3
T11
Muff$ SEHDVCB 550
11622/08
11624/08
ASA
T X30
17B3
TS7:MT4
T12
T22
TS7:MT14
11619/08
T15
TS7:MT7
11642/08
17B6
11645/08
11632/08
11633/08
TS7:MT8
T16
M7
11618/08
ASA
TX30
T13
TS7:MT5
ASA
TX30
11643/08
17B4
ASA
TX30
17BD
ASA
TX30
11626/08
11644/08
ASA
TX30
17B7
11629/08
TS7:MT6
T14
(4)15B4
Z$lt
H$iztrafos
ASA
T X30
TS7:LD1
T04
T01
TS7:MD5 11159/06
11160/06
T02 11621/08 11614/08 T03
TS7:MD1
TS7:MD3
17B5
11612/08
11611/08
ASA
TX30
M5
ASA
TX30
fr$i:
Rittal-Schrank
Anschlußkast$n Polycarbonat
17BF
Anschlußsäul$ BEWAG
(4)15B5
M4
2 x Kunststoff-Rohr
di = 200 mm x 2 m
11636/08
11620/08
11617/08
11615/08
M1
Dummy l = 15 m
Fig. 17: 156th load cycle T on dummy
11609/08
TS7:MD4
11616/08 T0711606/08
11164/05 10402/99 TS7:MD6
T05
T08
TS7:LD2
TS7:MD2
T06 11637/08
V$rsuchsaufbau Südkab$l
1524.2081038
Lag$ d$r T$mp$raturm$ßst$ll$n
(nicht maßstäblich)
Stand 17.03.2009
Fig. 14: positions of 24 pcs. temperature sensors
The PQ test were running under all whether conditions
down to temperatures at –20°C (see picture 15).
All accessories were equipped with inductive type PD
sensors. Omicron type pick-up sensors were used for
regular PD measurements whereas IPEC type sensors
were used for a long term monitoring of the PD activities
during the PQ test (see pictures below). During the test no
PD from the testing objects could be observed.
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- SHORT CIRCUIT CURRENT TESTS:
The contact system of thew compact sealing end was
tested by short time withstand current of 63 kA for 3 sec.
with 170 kA peak current.
The tests were passed successfully without any
recognized effects on the plug-in contact system (see
picture 25).
Fig. 18 (left): inductive sensors at back-to-back joint
Fig. 19 (right): inductive sensor at OSE
After the PQ test has passed 180 load cycles (90°C 95°C) and 8570 h AC voltage the final impulse tests has
been carried out on cable samples. After successful
passing the IEC requirements
BIL test: 1550 kV
SIL test 1175 kV
an increased impulse test with 1675 kV was passed.
Finally, the investigation of all accessories has been
performed in terms if any deteriorations were visible (see
pictures below). The inspection was without any findings.
Fig. 20 (left): 500 kV PQ test – investigation joint
Fig. 21 (right): 500 kV PQ test – investiagation OSE
ADDITIONAL QUALIFICATION TESTS
Beside the required tests according the IEC 62067
standard additional tests have been carried out:
Fig. 24 (left): Set-up three phase 63 kA / 3 sec.
Fig. 25 (right): Common plug-in SE contact after test
- ADVANCED DIELECTRIC TESTS
Sample tests with increased testing levels have been
carried out with the compact termination system
consisting of SF6 sealing end of type EHSVS and
compact OSE of type EHFVCS and a 500 kV cable
(Fig. 26).
The passed testing levels were:
Lightning impulse voltage: 1675 kV
Switching impulse voltage: 1240 kV
AC testing voltage:
640 kV / 1h
- DIELECTRIC TESTS WITH PORCELAIN INSULATOR
With the requirement to use porcelain type insulators for
special applications the compact OSE was tested
accordingly (see picture below Fig. 27).
- TESTS OF THE TRANSFORMER SEALING END
The transformer sealing end of type EHTVS 550 shows
the identical design to the compact SF6 sealing end. Only
the connection interface to the internal transformer link
shows an additional HV electrode to shield the connection
area.
The plug-in end sealing end was installed head first in a
transformer cable box and dielectrically tested (see
picture) in an oil immersed environment.
The AC testing voltage was 493kV accompanied by PD
measurements. After AC test transient testing voltages
according to the BIL and SWIL were applied. The testing
voltage was applied by a compact OSE (see picture
below) to the set-up.
Fig. 22 (left): Set-up transfromer 550 kV cable system
Fig. 23 (right): 550 kV transformer compact SE
Fig. 26 (left): Sample test with increased voltages
Fig. 27 (right): Tests of 500 kV compact porcelain OSE
- SHORTENED PQ-TEST WITH JOINT IN AIR
Fig. 28: Shortened PQ-test of outdoor installed joint
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8th International Conference on Insulated Power Cables
A.3.6
In order to verify installation in air of the joint 104 load
cycles at 500kV, (approx. 5000 h voltage) were applied to
the one-piece silicone-rubber joint (see picture above) of
type SEHDV550. The joint passed the test and the final
investigation gave no hint for any deteriorations.
ON-SITE INSTALLATIONS (EXAMPLES)
The new cable system has been installed successfully
and went into operation around the world, in North Africa,
China, Colombia, Russia (all for voltage level 500 kV) and
other locations demonstrating the progress and
experiences in this voltage level under various installation
conditions. The next pictures show some relevant
references:
- 500 kV transformer connection to GIB
In this application the cable is installed headfirst to the
transformers cable box:
Fig. 31: Installed one piece joint SEHDVCB
- porcelain insulators with compact OSE
For special dry climate pollution conditions customers
require porcelain insulators.
Fig. 29: 15 pcs. 500 kV compact transformer SE
- Connection to GIB:
A typical vertical installation of the compact SF6 sealing
end is shown in Fig. 30:
Fig. 32: EHV compact OSE with plug-in technology
and porcelain insulators
For cold climate conditions below –30°C a special heating
system has been developed to enable low temperature
operation of the compact OSE (Fig. 33).
Fig. 30: GIB-compact SF6-plug-in SE
- typical joint installation:
The joint installation requires a concrete bottom for
installation the needed cable clamping beside the joint to
take the mechanical forces from the cable away from the
joint.
Fig. 33: 500 kV compact OSE with external heating for
lower temperatures
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8th International Conference on Insulated Power Cables
- typical compact OSE installation
The pre-fabricated insulator part allows an short time
installation work on-site [3] as it can be pre- tested and
fully pre-assembled shipped to the installation site. The
installation work can be widely reduced to the installation
of the plug-in part only.
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CONCLUSIONS
An advanced 500kV XLPE cable system with prefabricated accessories and plug-in type terminations for
conductor cross sections up to 2500 mm² has been
developed and qualified. All qualification tests have been
carried out according IEC 62067 standard.
Additional qualification tests give evidence for higher
dielectric withstand, short circuit current withstand and
application under various installation conditions.
This system has been successfully installed around the
world at several projects for the 500kV level and
demonstrate the state of the art technology of 500 kV
XLPE cable systems.
REFERENCES
Fig. 34: 500 kV compact OSE with plug in technique in
Colombia
A new mobile and compact resonance testing system has
been developed to carry out commissioning tests with
increased AC voltages even at remote locations (Fig. 35,
[4]).
[1] staff report “First 525kV XLPE extra high voltage
cables destined for Dachaoshan”, Modern Power
Systems, December 2000, pp 39-41
[2] S. Sadler, S. Sutton, H. Memmer, J. Kaumanns
“1600MVA Electrical Power Transmission with an
EHV-XLPE Cable in the Underground of London”,
Proceedings
CIGRÈ
2004,
no.
B1-108,
International Council on Large Electrical Systems
(CIGRÈ), Paris, 2004
[3] J. Kaumanns, G. Schröder, A. Weinlein, V. Stroot, J.
Lehnhäuser: 400 KV XLPE-Insulated cable systems
with dry plug-in outdoor terminations, Jicable’07,
paper A.1.2
[4] A. Weinlein, G. Schröder, H. Geyer, 2011, On-site
testing with compact a.c. test-system at the first 500
kV XLPE cable project in South America, Jicable’11,
paper C.4.1
[5] IEC 62067 Ed.1.1 2006-03, Power cables with
extruded insulation and their accessories for rated
voltages above 150 kV (Um = 170 kV) up to 500 kV
(Um = 550 kV) - Test methods and requirements
GLOSSARY
Fig. 35: 500 kV AC on-site test
ACTUAL CHALLENGES
The actual challenge for the new cable system is a huge
500kV project Skolkovo in Moscow/Russia: The delivery
consists of 70km XLPE cable with a conductor cross
section of 2500mm² showing oxidised wires for reduced
skin effect losses. A total of 180 buried joints (cross
bonded type SEHDVCB 550) and 38 compact OSE of
type EHFVS 550 with plug in technology have to be
installed.
AC
(E)HV
GIB
GIS
HFCT
(O)SE
PD
PQ
XLPE
Alternating Current
(Extra) High Voltage
Gas Insulated Bushing
Gas Insulated Switchgear
High Frequency Current Transformer
(Outdoor) Sealing End
Partial Discharge(s)
Prequalification
Cross-Linked Polyethylene
Order intake was early 2011 and commissioning is
planned for 2011/2012.
Jicable’11 – 19 – 23 June 2011, Versailles - France