ABB RELION REX640 - 4.7.1.5 Operation principle

Input Description
Necessary when EF detection Mod GFC is set
to "Io AND IoRef"
U3P Three-phase voltages
URES
3
Residual voltage (measured)
Necessary when EF detection Mod GFC is set
to "Io OR Uo" or "Io AND Uo". Necessary also
if only main voltages are available but Phase
voltage Meas is set to "Accurate".
See the preprocessing function blocks in this document for the possible
signal sources. The GRPOFF signal is available in the function block called
Protection.
There are a few special conditions which must be noted with the configuration.
Table 905: Special conditions
Condition Description
U3P connected to real measurements The function can work with any two phase
voltage channels connected but it is recom-
mended to connect all three voltage chan-
nels.
Improper analog channel configuration causes a validation error if the analog
channels are not completely configured or they do not match with certain settings.
For troubleshooting, check the contents of this chapter and also the preprocessing
blocks in this document. The configuration can be written to the protection relay
once the mismatch is corrected.
4.7.1.5 Operation principle
The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "on" and "off".
The function consists of sub-functions which are described in the next sections.
3
Can be connected to GRPOFF if EF detection Mod GFC is set to "Io" or "Io AND IoRef" or Phase
voltage Meas is set to "Ph-to-ph without Uo"
Protection functions 1MRS759142 F
944 REX640
Technical Manual