Three-Phase Underexcitation Protection 40; Identification; Function Block; Functionality - ABB RELION 620 Series Technical Manual

1MAC504801-IB E
4.7.3
4.7.3.1
4.7.3.2
4.7.3.3
620 series ANSI
Technical Manual

Three-phase underexcitation protection 40

Identification

This function is available in REM620 Ver.2.1 only.
Function description
Three-phase underexcitation protection

Function block

40
I3P
U3P PICKUP
EXT_LOS_DET
BLOCK
BLK_TRIP
BLK_PICKUP
FR_TIMER
GUID-5DA20991-E63D-4243-8719-8CC3FD730266 V1 EN
Figure 244: Function block

Functionality

The three-phase underexcitation protection 40 is used to protect the synchronous machine
against the underexcitation or loss of excitation condition.
The protection is based on the offset-mho circular characteristics on the impedance plane.
The function calculates the apparent impedance from the machine terminal voltages and
currents. If the impedance vector enters the offset-mho circle, the function gives the
operating signal after a set definite time. The operating time characteristics are according
to definite time (DT).
This function contains a blocking functionality. It is possible to block the function outputs,
timer or the function itself, if desired.
IEC 61850
identification
UEXPDIS
TRIP
Section 4
Protection functions
IEC 60617 ANSI/IEEE C37.2
identification device number
X< 40
513