Setting Guidelines - ABB REC670 Applications Manual

Section 9
Voltage protection
9.4.3
242
U1
Ud>
U2
Gen
IEC06000389 V1 EN-US
Figure 98: Supervision of fuses on generator circuit voltage transformers

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 as applicable.
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 transformer ratios, different voltage levels e.g. the voltage
measurement inside the capacitor bank can have a different voltage level but the
difference can also e.g. be used by voltage drop in the secondary circuits. The
setting is normally done at site by evaluating the differential voltage achieved as a
service value for each phase. The factor is defined as U2 · RFLx and shall be equal
to the U1 voltage. Each phase has its own ratio factor.
To Protection
To Excitation
en06000389.vsd
1MRK 511 401-UEN A
SEMOD153915-5 v3
Bay control REC670 2.2 IEC
Application manual