Completing The Test; Full Scheme Distance Protection, Mho Characteristic Zmhpdis (21) - Hitachi Relion 670 Series Commissioning Manual

Section 11
Testing functionality by secondary injection
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-ground loop ECG, test point 1, according to figure 25. Compare the result of the
measurement with the expected value according to table 23.
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. Repeat steps
and table 23.
4. Repeat steps
figure
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 the original values, if 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
Consider releasing of the zone to be tested by setting the phase selector FMPSPDIS to Enabled.
The programming of the autorecloser function SMBRREC (79) determines if three-phase or single-phase
trip is initiated as result of the test.
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.
98
1 to 2 to find the operate values for the remaining test points according to figure
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.
1 to 3 to find the operate value for the phase-to-phase fault in A - C according to
26 and table 24.
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1MRK506371-UUS Rev. M
"Preparing the IED to verify
Line distance protection REL670
Commissioning manual
25
M13906-301 v5
M14944-3 v10
settings".