ISA T 2000 - Page 67

DOC. MIE11110 Rev. 5
Page
67
of
110
The selected current output is connected to the VT burden, after
having opened the secondary.
Output connection:
- N. 2 Low current connection cables.
- N. 2 Clamps.
The operator selects accordingly the current range for the test.
There are two tests:
. Protection threshold: start the test, and slowly increase the
current. As the protection intervenes, the current drops to zero;
the current meter holds the last metered value, that is the
threshold. Consider that the intervention is timed, so the current
should be increased slowly.