Operation Principle - ABB RELION REX640 Technical Manual

1MRS759142 C
4.2.7.5
REX640
Technical Manual
Table 539: Analog inputs
Input
IRES
URES
See the preprocessing function blocks in this document for the
possible signal sources.
There are a few special conditions which must be noted with the configuration.
Table 540: Special conditions
Condition
URES 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".
For WPWDE, certain notations and definitions are used.
Residual voltage Uo = (UA+UB+UC)/3 = U
sequence voltage
Residual current Io = -(IA+IB+IC) = 3×- I
current
The minus sign (-) is needed to match the polarity of calculated and
measured residual currents.
The operation of WPWDE can be described with a module diagram. All the modules
in the diagram are explained in the next sections.
Protection functions
Description
Residual current (measured or calculated)
Residual voltage (measured or calculated)
Description
The function requires that all three voltage
channels are connected for calculating the
VT connection must be
residual voltage. Setting
"Wye" in that particular UTVTR.
, where U
0
, where I
0 0
Section 4
= zero-
0
= zero-sequence
497