Operation Principle - ABB RELION REX640 Technical Manual

1MRS759142 C
4.7.3.5
REX640
Technical Manual
Table 867: Special conditions
Condition
U3P connected to real measurements
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 UEXPDIS can be described using a module diagram. All the
modules in the diagram are explained in the next sections.
I_A
I_B
I3P
I_C
I
1
U_A_AB
U_B_BC
U3P
U_C_CA
U
EXT_LOS_DET
BLOCK
GUID-773D0734-4B6A-4833-95A4-C52297885A89 V1 EN
Figure 505: Functional module diagram
Impedance calculation
This module calculates the apparent impedance based on the selected voltages and
currents. The Impedance Meas mode and Phase Sel for Z Clc settings determine which
voltages and currents are to be used. If the Impedance Meas mode is set to "1Phase-
earth" or "1Phase-phase", the Phase Sel for Z Clc setting is needed for determining
which phase or phase-phase voltages ("A or AB", "B or BC" and "C or CA") and
currents should be used for calculating the impedance.
Description
The function can work with one voltage channel
connected (
or BC" or "C or CA"), if the setting
Meas mode is se to "1Phase-to-earth" or "1Phase-
to-phase".
The function requires that all three voltage
channels are connected if
is set to "3Phase-to-earth", "3Phase-to-phase" or
"Pos sequence".
Impedance
reach check
Impedance
calculation
External
loss
1
detection
Blocking
logic
Section 4
Protection functions
Phase Sel for Z Clc set to "A or AB", "B
Impedance
Impedance Meas mode
Timer
OPERATE
t
START
933