Setting Guidelines - ABB RELION 670 Series Applications Manual

Section 9
Voltage protection
The application to supervise the voltage on two voltage transformers in the generator circuit
is shown in figure 282.
Gen
IEC06000389 V1 EN-US
Figure 282: Supervision of fuses on generator circuit voltage transformers
9.5.3

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
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 ·
be equal to the U1 voltage. Each phase has its own ratio factor.
UDTrip : The voltage differential level required for tripping is set with this parameter. For
application on capacitor banks the setting will depend of the capacitor bank voltage and the
number of elements per phase in series and parallel. Capacitor banks must be tripped before
excessive voltage occurs on the healthy capacitor elements. The setting values required are
normally given by the capacitor bank supplier. For other applications it has to be decided case
by case. For fuse supervision normally only the alarm level is used.
482
To Protection
U1
Ud>
U2
To Excitation
en06000389.vsd
1MRK 504 152-UEN B
SEMOD153915-5 v3
RFLx and shall
Application manual