They should change to logical 0 as follows:• Signal 3PH after about 25ms• Signal BLKU after about 50ms• Signal BLKZ after about 200ms6.8.1.2 Measuring the operate value for the negative sequence function1. Simulate normal operating conditions with the three-phase currents in phasewith their corresponding phase voltages and with all of them equal to their ratedvalues.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 the equation are phasors.3 U2× UL 1 a2 UL 2 a+× UL3×+=EQUATION707 V1 EN (Equation 37)Where:UL1 , UL2 and UL3IEC00000275 V1 EN= the measured phase voltages23 31 0, 5 2ja e jp×= × = - +IECEQUATION00022 V1 EN4. Compare the result with the set value (consider that the set value 3U2> is inpercentage of the base voltage UBase) of the negative-sequence operatingvoltage.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-sequencecurrent according to the equation.Observe that the currents in the equation are phasors.21 2 323 L L LI I a I a I× = + × + ×IECEQUATION00021 V1 EN (Equation 40)Where:1 2 3L L LI I and I,IECEQUATION00020 V1 EN= the measured phase currents1MRK 502 049-UEN A Section 6Testing functionality95Commissioning manual
