Analog Channel Configuration; Operation Principle - ABB RELION REX640 Technical Manual

Section 4
Protection functions
4.4.5.4
4.4.5.5
758
full load current, which can severely heat the motor. MNSPTOC detects the large
negative-sequence current and disconnects the motor.
The function contains a blocking functionality. It is possible to block the function
outputs, timers or the function itself.

Analog channel configuration

MNSPTOC has one analog group input which must be properly configured.
Table 695: 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 MNSPTOC can be described by using a module diagram. All the
modules in the diagram are explained in the next sections.
I
I3P
2
BLOCK
GUID-B891CD1F-358A-45FB-9219-0DADB3A20BC2 V1 EN
Figure 418: Functional module diagram
Level detector
The calculated negative-sequence current is compared to the Start value setting. If the
measured value exceeds the Start value setting, the function activates the timer
module.
Description
Three-phase currents
Timer
Level
t
detector
t
1MRS759142 C
OPERATE
START
BLK_RESTART
Technical Manual
REX640