TerminologyThe busbar voltage UB is a shorter notation for the measured voltages UL1, UL2,UL3 or Uij, where Uij is the phase-phase voltage, Uij = Ui -Uj, or Ui, where Ui isone single-phase-to-earth voltage.IL is a shorter notation for the measured load current; it is to be used instead of thethree-phase quantities IL1, IL2, IL3 or the two-phase quantities Ii and Ij, or single-phase current Ii.Also note that for simplicity, the Parameter Setting menu structuresincluded in the following procedure are referred to universally asVCP1, for example, Main menu/Settings/Setting Group N/Control/TransformerVoltageControl(ATCC,90)/TR1ATCC:x/TR8ATCC:x/Time/t1 and t2l.For cases where single-mode voltage control is implemented, the Parameter Settingmenu structure includes TR1ATCC:1 instead of the parallel designator TR8ATCC:1.13.10.3.1 Secondary test SEMOD175185-145 v5The voltage control function performs basic voltage regulation by comparing acalculated load voltage (UL) against a voltage range defined by setting UDeadband(with upper and lower limits U2 and U1 respectively). The calculated load voltageUL represents the secondary transformer bus voltage UB adjusted for Load dropcompensation (LDC) where enabled in settings.Note that when LDC is disabled, UB equals UL.When the load voltage UL stays within the interval between U1 and U2, no actionwill be taken.If UL < U1 or UL > U2, a command timer will start, which is constant time orinverse time defined by setting t1 and t1Use. The command timer will operatewhile the measured voltage stays outside the inner deadband (defined by settingUDeadbandInner).If UL remains outside of the voltage range defined by UDeadband and thecommand timer expires, the voltage control will execute a raise or lower commandto the transformer tap changer. This command sequence will be repeated until UL isbrought back within the inner deadband range.13.10.3.2 Check the activation of the voltage control operation SEMOD175185-537 v81MRK 502 073-UEN A Section 13Testing functionality by secondary injectionGenerator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062 241Commissioning manual
