• Signal 3PH after about 25ms• Signal BLKU after about 50ms• Signal BLKZ after about 200ms9.4.2.2 Measuring the operate value for the negative sequence function M1405-46 v12Measure the operate value for the negative sequence function, if included in theIED.1. Simulate normal operating conditions with the three-phase currents in phasewith their corresponding phase voltages and with all of them equal to theirrated values.2. Slowly decrease the measured voltage in one phase until the BLKU signalappears.3. Record the measured voltage and calculate the corresponding negative-sequence voltage according to the equation (observe that the voltages in theequation are phasors):3 2 12⋅ + ⋅ + ⋅U U U UL L2 L3= a aEQUATION707 V2 EN-US (Equation 1)Where:UL1 , UL2 and UL3IEC00000275 V1 EN-USare the measured phase voltages23 31 0, 5 2ja e jp×= × = - +.IECEQUATION00022 V2 EN-US4. Compare the result with the set value of the negative-sequence operatingvoltage (consider that the set value 3U2> is in percentage of the base voltageUBase).5. Repeat steps 1 and 2. Then slowly increase the measured current in one phaseuntil the BLKU signal disappears.6. Record the measured current and calculate the corresponding negative-sequence current according to the equation (observe that the currents in theequation are phasors):21 2 323 L L LI I a I a I× = + × + ×IECEQUATION00021 V1 EN-US (Equation 2)Where:1 2 3L L LI I and I,IECEQUATION00020 V1 EN-USare the measured phase currentsSection 9 1MRK 511 425-UEN ATesting functionality by secondary injection74 Bay control REC650 2.2 IECCommissioning manual
