Megger L1070, Инструкция по эксплуатации

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AVTM651070 Rev B Nov 2006
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Fault Locating with the L1070/L1071
Introduction
Fault locating determines the position of an insulated break on an underground
conductor. In the case of an insulation fault, some of the signal will return to the
TRANSMITTER attached to the GROUND ROD through a break in the
insulation.
Figure 16: Signal Return through an Insulation Fault to Earth
Signal Return through an Insulated Fault
It is generally a good idea to locate the conductor path before attempting to fault
locate. If, during the path locate, an unusual amount of signal loss occurs, a part
of the signal has escaped to ground in the last several feet.
Note: Signal would go to ground at a grounded splice point, which would act as
a fault during the path and fault locate.
Once the path is determined and there is a general area where a fault is expected,
additional current can be forced to flow through the fault by disconnecting and
isolating the far access point. If the current has no path to ground at the far
access point, it will be forced to seek ground at the fault. This will increase the
current in the soil at the fault and detection of the fault.