terminal side of the generator) and ANGLE (the angle between the third-harmonicvoltage phasors U3N and U3T). The value of E3 should be close to the following value:( ) ( )2 23 N 3T 3TE3 U U cos(ANGLE) U sin(ANGLE)= - × + ×EQUATION2076 V1 EN-US (Equation 103)Make sure that ANGLE has a value bigger than 125°2. Read the value of DU (differential voltage). The value of DU should be close to thefollowing value:( ) ( )2 23 N 3T 3TDU U U cos(ANGLE) U sin(ANGLE)= + × + ×EQUATION2078 V1 EN-US (Equation 104)3. Read the value of BU (bias voltage:Beta ·U3N). The ratio DU/BU should be well below 1 fora non-faulted generator.4. After synchronization of the generator the ratio DU/BU is checked for different loadlevels of the generator. These different monitoring of load levels should be the base forthe setting ofbeta.If the function is used with the option of neutral point measurement only the test isperformed by check of this voltage. The operate value should be above the measuredresidual third-harmonic voltage in the neutral point at normal operation (non-faultedgenerator).12.6.6.3 Completing the test SEMOD158990-34 v3Continue to test another function or end the test by changing theTestMode setting toOff.Restore connections and settings to their original values, if they were changed for testingpurposes.12.6.7 Loss of voltage check LOVPTUV SEMOD175023-3 v5Prepare the IED for verification of settings as outlined in section "Requirements" andsection "Preparing for test" in this chapter.12.6.7.1 Measuring the operate limit of set values SEMOD175023-7 v71. Check that the input logical signals BLOCK, CBOPEN and VTSU are logical zero.2. Supply a three-phase rated voltage in all three phases and note on the local HMI that theTRIP logical signal is equal to the logical 0.3. Switch off the voltage in all three phases.After settTrip time a TRIP signal appears on the corresponding binary output or on thelocal HMI.Note that TRIP at this time is a pulse signal, duration should be accordingto settPulse.4. Inject the measured voltages at rated values for at least settRestore time.5. Activate the CBOPEN binary input.6. Simultaneously disconnect all the three-phase voltages from the IED.No TRIP signal should appear.7. Inject the measured voltages at rated values for at least settRestore time.8. Activate the VTSU binary input.Section 12 1MRK 502 067-UEN BTesting functionality by secondary injection192Commissioning manual
