Operation Principle - ABB RELION REX640 Technical Manual

1MRS759142 C
4.2.8.5
REX640
Technical Manual
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 549: Special conditions
Condition
U3P connected to real measurements
URES calculated
UNEUT calculated
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.

Operation principle

The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "on" and "off".
The operation of the third harmonic-based stator earth-fault protection function can be
described using a module diagram. All the modules in the diagram are explained in the
next sections.
U_3H_A
U_3H_B
U3P
U_3H_C
U_3H_RES
URES
U_3H_N
UNEUT
GCB_CLOSED
BLOCK
GUID-380D23D3-1814-43D0-8E7C-286A960998EA V2 EN
Figure 280: Functional module diagram
Desription
The function can work with at least one voltage
channel connected.
The function requires that all three voltage
channels from the terminal side are connected to
calculate residual voltage. Setting
must be "Wye" in that particular UTVTR.
The function requires that all three voltage
channels from the neutral side are connected to
calculate residual voltage. Setting
must be "Wye" in that particular UTVTR.
rd
3
Differential
harmonic
calculation detector
calculation
Bias
calculation
Section 4
Protection functions
VT connection
VT connection
Timer
OPERATE
Level
t
START
INT_BLKD
511