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4
Performing measurements
Prepare devices
If the T 22/13 B is operated in combination with other devices or as part of a test van, it
involved
has to be ensured before starting the measurement that the necessary safety
requirements are met and that all devices involved are set to the correct operating mode.
If the conversion of the fault resistance is to be followed live on a TDR, first there must be
a reference image recorded with it, then the recording of the fault trace must be started.
4.1
Conversion of fault resistance (Burning)
Procedure
To conduct a conversion of the fault resistance perform the following steps:
Step
Detailed information on how to proceed can be found in the user guides of
the involved devices or the test van.
Action
1
Turn mains switch
Result: Green mains control lamp
2
Turn regulating transformer
will go.
3
At the start, the switch for ammeter
able to better perceive the onset of the burning process.
When opening the spark gap (see step 8), at the latest, the switch for
ammeter must be set to 30 A, as the output current of the Burn Unit is not
displayed in the 0.3 range with an open spark gap.
4
Press the "HV On" button
Result: The indicator lamp "HV On"
5
Increase the voltage by slowly turning the regulating transformer
clockwise, while observing the voltmeter
CAUTION
When burning on low-voltage cables, the voltmeters has to be
observed particularly closely. Under certain conditions, the
change of the fault can lead to a ramp-up of the voltage. This
could result in values that exceed the maximum permissible
cable voltage. In this case, a shutdown should be carried out
immediately via the mains switch
As the T 22/13 B 15 kV Burn Unit is equipped with a peak
voltmeter, even transient voltage peaks are displayed so that
risks to the cable can be avoided.
6
Increase the voltage until a voltage flashover occurs at the fault position.
Result: At the moment of the flashover, the output current increases abruptly
while the displayed output voltage decreases visibly.
on.
is on.
and spark gap
may be set to 0,3 A in order to be
.
is on.
.
as far anticlockwise as it
.
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