21
Recommendations for
selection of test
voltage and duration
Before one starts the actual test, the currently set test parameters should be checked and
adapted if needed.
The requirements for a meaningful cable test are found in Harmonization Documents
HD 620 S1:1996 and HD 621 S1:1996 and often in company-internal testing guidelines as
well.
The following table provides some generally accepted test parameters for different
applications:
Application Test voltage Test duration in minutes
VLF test on cables with extruded
insulation
3Uo 30 … 60
DC test on PILC (Paper Insulated
Lead Covered) cables
8Uo 15
Sheath test on…
… PVC cables
… medium voltage PE cables
… high voltage PE cables
3 kV
5 kV
10 kV
5
5
1
Adapting the test
parameters
To adjust the test settings, select Test setup from the settings menu (see section 4.1).
The amount of adjustable test parameters differs between the different operation modes.
Menu item Description
Test voltage The test voltage can be set in increments of 0.1 kV.
For sheath test and pinpointing, the selected value represents the
initial voltage level which can still be cautiously increased up to the
voltage threshold specified under Range (see next page) during
operation.
Test
frequency
For the modes “VLF Sinus” and “VLF Rectangle”, the test frequency
can be set in increments of 0.01 Hz between 0.01 Hz and 0.1 Hz.
Alternatively, automatic frequency calculation (auto
activated.
At the start of a voltage test, automatic load recognition is conducted.
Since the maximum permitted test frequency depends on the
determined cable capacitance and the set test voltage (see
section 2.3), it can happen that the test cannot be performed with the
set but with a decreased frequency.
If test frequency is set to auto, the switch to the lower frequency is
automatically performed. But if the parameter is set to a fixed value,
the system prepares for a switch to the highest possible frequency
which requires the confirmation of the user (20 second timeout).
To Next Page
Loading...
Need help?
General
