VLF CR series
Portable VLF test systems for testing medium
voltage cables according to IEC 60502-2 and IEEE 400.2
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VLF, DC and sheath fault testing in
one device
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Portable thanks to two-part construction
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High test capacitance
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Integrated discharge system
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Reporting
DESCRIPTION
The VLF CR Series are portable, efficient, high-performance
systems for testing cables with 0.1 Hz cosine-rectangular
voltages, in keeping with IEC and IEEE standards. In accord-
ance with these guidelines, the dielectric strength of cables
and joints must be checked after installation or repair.
Three portable systems are available, each with different volt-
age levels (28, 40 and 60 kV):
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VLF CR-28 up to 15 kV rated cables
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VLF CR-40 up to 23 kV rated cables
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VLF CR-60 up to 36 kV rated cables
High test capacity
The systems consist of a control unit and an HV unit. Because
of their two-part construction, the systems are easy to
transport.
One of the advantages of the cosine-rectangular test method
is the high test capacitance of up to 5 μF at 0.1 Hz. This test
capacitance allows all three phases to be tested simultaneously
with the standardized test frequency of
0.1 Hz.
Proven procedure
Using 0.1 Hz cosine-rectangular voltage, weak points in the
cable can be safely broken down. The benefits of the VLF
method using 0.1 Hz cosine-rectangular voltage have been
confirmed by numerous scientific examinations and practical
field trials. Since the patent was granted in 1987, more than
2,500 systems have been sold worldwide. This proven voltage
shape is recommended by the CENELEC HD 620 and HD 621
harmonisation documents, the IEC 60502-2 standard and the
IEEE 400.2 standard.
DC testing, sheath fault testing and pinpointing
By switching to DC testing, the cables and connected sub-
stations can be tested with negative and positive DC voltage.
Aside from cable and sheath testing, the test systems can also
be used to precisely pinpoint sheath faults (in combination
with a step-voltage probe e.g. the ESG NT).
Transport container VLF CR-60
Test capacitance as function of the test voltage
Maximum safety
The integrated discharge and breakdown detection systems
maximise user safety. Measuring the leakage current serves
to develop a relative evaluation of cable insulation quality;
test results can be archived for further processing through
the logging function.
Because of its compact design and high voltage level, the
VLF CR-60 is ideally suited for testing 30/36 kV cables in
offshore areas.
Testing offshore cables regularly is vital because any down-
time will result in massive financial losses.
VLF CR-60 kV in operation on the “Baltic 1“ wind park (Baltic sea).
The modified offshore system found in the VLF CR-60 meets
all applicable requirements for sea-bound operations.
Optional transport containers are also available, which
protect the system against water ingress. The VLF CR-60 can
be stored and transported easily in these containers. The
VLF CR-60 can be stored and transported easily in these
containers.
VLF CR series
Portable VLF test systems for testing medium
voltage cables according to IEC 60502-2 and IEEE 400.2