ABB REC670 Applications Manual page 247

1MRK 511 401-UEN A
Bay control REC670 2.2 IEC
Application manual
U1
Ud>L1
U2
Ph L3
Ph L3
IEC06000390 V3 EN-US
Figure 97: Connection of voltage differential protection VDCPTOV function to
detect unbalance in capacitor banks (one phase only is shown)
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 98.
Single earthed wye
Ph L2
Ud>L1
U1 U2
Ph L3
Ph L2
Section 9
Voltage protection
Double wye
Ph L2
IEC06000390_1_en.vsd
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