Megger PFL22M1500 Series, Руководство пользователя

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AVTMPFL22M Rev 1 April 2011
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Description of Voltage Decay
Voltage Decay is probably only used around 8% of the time, but it is especially
useful when a fault breaks down and then reseals itself. This can be termed a
“flashing or pecking” fault. Voltage decay can also be used where the voltage
required to breakdown the fault cannot be achieved with the surge generator.
In Voltage Decay we typically use a High Voltage d.c. source, a voltage divider
and the MTDR100 which is operating as a transient recorder.
HV DC is applied and the voltage increased until the fault breaks down, and a
flashover occurs. During this flashover (the point of fault) the resultant
transients are reflected back and forward between the fault and the dc source.
These transients are detected by the voltage divider and fed to the MTDR where
they are subsequently displayed.
Typical Trace
Distance / 2 = Fault Distance