10.12.5.1 Measuring the operate limit1. Set the test point (|Z| fault impedance and ZF impedance phase angle ) for acondition that meets the requirements in table 20.2. Subject the IED to healthy normal load conditions for at least two seconds.3. Apply a fault condition.Check that the distance-to-fault value displayed on the HMI complies withequations 46, 47 and 48p ZxX1------- 100×=EQUATION123 V1 EN (Equation 46)in % for two- and three-phase faultsx3 Zp 100X0 2 X1×= ×+ ×EQUATION124 V1 EN (Equation 47)in % for single-phase-to-earth faultsp 3 Z× xX0 2 X1 XM±×+--------------------------------------------- 100×=EQUATION125 V1 EN (Equation 48)in % for single-phase-to-earth faults with mutual zero sequence current.Where:p = the expected value of a distance to fault in percentZx = set test point on the test setX0 = set zero-sequence reactance of a lineX1 = set positive-sequence reactance of a lineXM = set mutual zero-sequence impedance of a line10.12.5.2 Completing the testContinue to test another function or end the test by changing the TestMode setting toOff. Restore connections and settings to their original values, if they were changed fortesting purposes.10.12.6 Limit counter L4UFCNTThe Limit counter function L4UFCNT can be tested by connecting a binary input tothe counter and applying pulses to the counter. The speed of the pulses must notexceed the cycle time of the function. Normally the counter will be tested when testingthe function that the counter is connected to, such as the trip function. When the1MRK 511 360-UEN A Section 10Testing functionality by secondary injectionBay control REC670 2.1 IEC 185Commissioning manual
