1. Keep all the current and voltage in normal balanced condition.2. Keeping the phase current at rated value, slowly reduce the voltage till it entersinto the respective zone mho characteristics and also below the set value of theunder voltage seal-in logic.3. Before the operate time delay of the respective zone, reduce the currentmagnitude so that the operating impedance moves out of the mhocharacteristics.4. The under voltage seal-in should give a START and TRIP after the operatetime delay is set for the under voltage logic.13.4.7.2 Completing the test GUID-93110921-550A-441F-A36F-901488CC41BB v3Continue to test another function or end the testing by setting the parameterTestMode to Off under Main menu/Tests/IED test mode/1: TESTMODE. Ifanother function is tested, then set the parameter Blocked to No under Main menu/Tests/Function test modes/Impedance/ZGVPDIS/1: ZGVPDIS for the function,or for each individual function in a chain, to be tested next. Remember to set theparameter Blocked to Yes, for each individual function that has been tested.13.4.8 Rotor earth fault protection with RXTTE4 and generalcurrent and voltage protection CVGAPC SEMOD158692-3 v2Prepare the IED for verification of settings as outlined in section "Requirements"and section "Preparing for test" in this chapter.13.4.8.1 Testing SEMOD158692-13 v2The protection function uses injection of an ac voltage to the generator field circuit.The COMBIFLEX voltage injection unit RXTTE4, Part No 1MRK 002 108-ABcontains a voltage transformer with a primary winding for connection to 120 or 230V, 50 or 60 Hz supply voltage. From the secondary winding of this internal voltagetransformer approximately 40 V AC is injected via series capacitors and resistorsinto the rotor circuit. The injected voltage is fed to a voltage input of the REG670IED. The current caused by the injection is fed to a current input of the REG670IED via a current transformer, which is amplifying the current ten times, as shownin figure 53.Section 13 1MRK 502 073-UEN ATesting functionality by secondary injection172 Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062Commissioning manual
