Operation Principle - ABB RELION REX640 Technical Manual

Section 4
Protection functions
4.4.1.5
736
Table 660: Analog signals
Input
I3P
See the preprocessing function blocks in this document for the
possible signal sources.
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 NSPTOC can be described using a module diagram. All the modules
in the diagram are explained in the next sections.
I
Level
2
I3P
detector
ENA_MULT
Blocking
BLOCK
logic
GUID-720B7E26-6DEB-4F2C-8684-453B4A33CC80 V1 EN
Figure 407: Functional module diagram
Level detector
The measured negative-sequence current is compared to the set Start value. If the
measured value exceeds the set Start value, Level detector activates the Timer
module. If the ENA_MULT input is active, the set Start value is multiplied by the set
Start value Mult.
The protection relay does not accept the Start value or Start value Mult
setting if the product of the settings exceeds the Start value setting
range.
Description
Three-phase currents
Timer
t
OPERATE
START
t
1MRS759142 C
REX640
Technical Manual