ABB RELION RET670, Commissioning Manual, Page: 127 / 328

When the load encroachment characteristic is deliberately set very
high in order not to have an influence, then the test points 2 and 5 can
be replaced by test point 7.
4. Repeat steps 1 to 3 to find the operate value for the phase-to-phase fault in A - C
according to figure 26 and table 21 .
11.4.2.2 Completing the test
Continue to test another function or end the test by changing the TESTMODE setting to
Disabled . Restore connections and settings to their original values, if they were changed
for testing purposes.
11.4.3 Full scheme distance protection, mho characteristic ZMHPDIS
(21)
Prepare the IED for verification of settings outlined in Section "Preparing the IED to
verify settings" .
Consider releasing of the zone to be tested by setting the phase selector FMPSPDIS to
Enabled .
Keep the current constant when measuring operating characteristics. Keep the current as
close as possible to its rated value or lower. But make sure it is higher than the set
minimum operating current.
Ensure that the maximum continuous current in an IED does not exceed four times its
rated value, if the measurement of the operating characteristics runs under constant
voltage conditions.
To verify the mho characteristic, at least two points should be tested.
In the following, three test points are proposed. The mho characteristic always goes
through the origin, which automatically gives a fourth point for the characteristic.
1MRK 504 165-UUS -
Section 11
Testing functionality by secondary injection
Transformer protection RET670 2.2 ANSI 121
Commissioning manual