5
Testing Between Transformers
1.
Following standard operating procedures, isolate both ends of
the cable under test using feed thru bushings, see NOTE 1.
2.
Attach Meter & Second probe to appropriate length live line
tools for the voltage being worked.
3.
Attach the Bushing adapters to Meter & Second probes.
4.
Insert the Meter probe with adapter into the energized bushing of
transformer and second probe into the open feed thru bushing
isolating cable under test. SEE NOTE 2.
5.
On a non-faulted cable the meter will momentarily read into the
red and diminish into the green area.
6.
On a faulted cable the meter will read within the red area.
7.
A pulsating meter reading indicates the presence of an internal
flashover.
8.
Discharge cable to ground after each test by contacting tested
cable with Meter probe and contacting a suitable ground with the
Second probe.
WARNING
– Failure to discharge cable could result in
death or serious injury, equipment damage, and/or false readings.
NOTE 1:
The section of cable under test must be isolated on both ends
and cannot be connected to/or through equipment or lighting arrestors.
NOTE 2:
The maximum reading during the hi-potting test is 100%.
100% represents approximately 70% of the line-to-ground source
voltage, i.e. 7.2kV X .70 = 5kV. This value is representative of a direct
fault on the cable. Readings near zero represent a good cable with little
or no cable leakage.