4.4.4.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Phase reversal protection PREVPTOC I2>> 46R
4.4.4.2 Function block
Figure 474: Function block
4.4.4.3 Functionality
The phase reversal protection function PREVPTOC is used to detect the reversed
connection of the phases to a three-phase motor by monitoring the negative phase
sequence current I
2
of the motor.
PREVPTOC starts and operates when I
2
exceeds the set limit. PREVPTOC operates
on definite time ( DT) characteristics. PREVPTOC is based on the calculated I
2
, and
the function detects too high I
2
values during the motor start-up. The excessive I
2
values are caused by incorrectly connected phases, which in turn makes the motor
rotate in the opposite direction.
The function contains a blocking functionality. It is possible to block function
outputs, timer or the function itself.
4.4.4.4 Analog input configuration
PREVPTOC has one analog group input which must be properly configured.
Table 762: Analog inputs
Input Description
I3P Three-phase currents
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.
4.4.4.5 Operation principle
The function can be enabled and disabled with the
Operation
setting. The
corresponding parameter values are "On" and "Off".
Protection functions
1MRS759142 F
838 REX640
Technical Manual
To Next Page
Loading...
