Setting Guidelines - ABB Relion REC670 Applications Manual

1MRK 511 358-UEN A
VDCPTOV function has a block input (BLOCK) where a fuse failure supervision (or MCB tripped)
can be connected to prevent problems if one fuse in the capacitor bank voltage transformer
set has opened and not the other (capacitor voltage is connected to input U2). It will also
ensure that a fuse failure alarm is given instead of a Undervoltage or Differential voltage alarm
and/or tripping.
Fuse failure supervision (SDDRFUF) function for voltage transformers. In many application the
voltages of two fuse groups of the same voltage transformer or fuse groups of two separate
voltage transformers measuring the same voltage can be supervised with this function. It will
be an alternative for example, generator units where often two voltage transformers are
supplied for measurement and excitation equipment.
The application to supervise the voltage on two voltage transformers in the generator circuit
is shown in figure 82.
Gen
IEC06000389 V1 EN-US
Figure 82: Supervision of fuses on generator circuit voltage transformers
8.4.3

Setting guidelines

The parameters for the voltage differential function are set via the local HMI or PCM600.
The following settings are done for the voltage differential function.
Operation : Off / On
GlobalBaseSel : Selects the global base value group used by the function to define ( IBase ),
( UBase ) and ( SBase ).
BlkDiffAtULow : The setting is to block the function when the voltages in the phases are low.
RFLx : Is the setting of the voltage ratio compensation factor where possible differences
between the voltages is compensated for. The differences can be due to different voltage
Application manual
To Protection
U1
Ud>
U2
To Excitation
en06000389.vsd
Section 8
Voltage protection
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