Setting Guidelines - ABB Relion 670 Series Applications Manual

Section 8
Voltage protection
VDCPTOV (60) 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 V2). 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 95.
Gen
ANSI06000389 V1 EN-US
Figure 95: 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 ), ( VBase )
SBase ).
and (
BlkDiffAtVLow : 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 transformer
ratios, different voltage levels e.g. the voltage measurement inside the capacitor bank can have a
214
To Protection
V1
Vd>
v2
To Excitation
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1MRK 511 358-UUS A
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Application manual