The phase and residual voltage preprocessing function UTVTR is used for setting up the three phase voltage measurement channels and residual voltage measurement. The input channels for UTVTR are from physical hardware.
The output channel U3P of UTVTR can be connected to different applications which require phase voltage, positive and negative sequence.
Outputs URES_MEAS and URES_CLC can be connected to different applications which require measured residual voltage or calculated residual voltage (from phase voltages), respectively.
The VTs' primary rated voltage can be set using Primary voltage setting. The setting Secondary voltage defines the nominal voltage of the VT's secondary winding. This is used as a reference to scale the measurements accordingly.
The Voltage (Uo) residual voltage settings are also used for scaling the calculated residual voltage in comparison to the measured residual voltage.
Voltage magnitude correction can be made using settings Amplitude Corr A, Amplitude Corr B and Amplitude Corr C for an external three-phase VT and Amplitude Corr setting for an external residual VT.
Voltage angle correction can be made using settings Angle Corr A, Angle Corr B and Angle Corr C for an external three-phase VT and Angle correction setting for an external residual VT.
The VT connection can be set using VT connection. For three phase-to-earth voltage measurements, VT connection can be set to "Wye", and for three phase-to-phase voltage measurements, VT connection can be set to "Delta".
The MINCB_OPEN input signal is connected through a relay binary input to the NC auxiliary contact of the MCB protecting the VT secondary circuit. The MINCB_OPEN signal receives information about the MCB open state. When MINCB_OPEN is active, the outputs ALARM and WARNING are activated.
Output WARNING is always internally active whenever output ALARM is active.