Pinpointing Sheath Faults in „ESG“ Mode
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6.2
Approaching the Fault
6.2.1
General Notes
With each coupled DC pulse, current flows into the ground at the position of the fault,
which forms voltage gradients around the fault position.
The step voltage, which can be measured on the surface, increases at the fault position
and changes polarity directly above the location.
This particular effect is most beneficial for pinpointing sheath faults, by measuring the
value as well as the polarity of the step voltage using two earth spikes and approaching
the deflection direction following the fault position.
The sheath fault is located in the direction of the earth spike
which is connected with the black measuring lead
The sheath fault is located in the direction of the earth spike
which is connected with the red measuring lead
To ensure a reliable indication of the direction, note the following guidelines for basic
handling:
•
The earth spikes should be placed along the suspected cable route if possible.
•
The indicator unit must be kept in a horizontal position along the cable run.
•
While approaching the fault location, the earth spikes must not get mixed
up and the alignment of the indicator unit must not change.
Technical principles
Orientation
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