1.
Supply the IED with healthy conditions for at least two seconds.
2.
Apply the fault condition and slowly decrease the measured impedance to find the
operate value for of the phase-to-earth loop L3, test point 1, according to figure
Compare the result of the measurement with the expected value according to table
.
The corresponding binary signals that inform about the operation of the phase selection
measuring elements are available in the local HMI under
Main menu/Test/Function status/Impedance Protection/PhaseSelection(PDIS, 21)/
FDPSPDIS:x.
3.
to find the operate values for the remaining test points according to
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.
to find the operate value for the phase-to-phase fault in L1 — L2
according to figure
and table
.
12.4.2.2
Completing the test
M13906-301 v5
Continue to test another function or end the test by changing the
TestMode setting to Off.
Restore connections and settings to their original values, if they were changed for testing
purposes.
12.4.3
Full scheme distance protection, mho characteristic ZMHPDIS
M14944-3 v10
Prepare the IED for verification of settings outlined in
section "Requirements" and section
"Preparing for test" in this chapter.
Consider releasing of the zone to be tested by setting the phase selector FMPSPDIS to
On.
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 502 067-UEN B
Section 12
Testing functionality by secondary injection
109
Commissioning manual
