11.4.2.1 Measuring the operating limit of set values M13906-73 v6Procedure:1. Supply the IED with healthy conditions for at least two seconds.2. Apply the fault condition and slowly decrease the measured impedance tofind the operate value for of the phase-to-earth loop L3, test point 1,according to figure 25. Compare the result of the measurement with theexpected value according to table 22.The corresponding binary signals that inform about the operation of the phaseselection measuring elements are available in the local HMI underMain menu/Test/Function status/Impedance Protection/PhaseSelection(PDIS, 21)/FDPSPDIS:x.3. Repeat steps 1 to 2 to find the operate values for the remaining test pointsaccording to figure 25 and table 22.When the load encroachment characteristic is deliberately setvery high in order not to have an influence, then the test points2 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 L1— L2 according to figure 26 and table 23.11.4.2.2 Completing the test M13906-301 v5Continue to test another function or end the test by changing the TESTMODEsetting to Off. Restore connections and settings to their original values, if they werechanged for testing purposes.11.4.3 Full scheme distance protection, mho characteristicZMHPDIS M14944-3 v10Prepare the IED for verification of settings outlined in Section "Preparing the IEDto verify settings".Consider releasing of the zone to be tested by setting the phase selector FMPSPDISto On.The programming of the autorecloser function SMBRREC determines if three-phase or single-phase trip is initiated as result of the test.Keep the current constant when measuring operating characteristics. Keep thecurrent as close as possible to its rated value or lower. But make sure it is higherthan the set minimum operating current.Ensure that the maximum continuous current in an IED does not exceed four timesits rated value, if the measurement of the operating characteristics runs underconstant voltage conditions.1MRK 505 378-UEN A Section 11Testing functionality by secondary injectionLine differential protection RED670 2.2 IEC 121Commissioning manual
