Loss Of Load Supervision Loflptuc (Ansi 37) - ABB RELION REX640 Technical Manual

Protection functions
Characteristic
Retardation time
Operate time accuracy in definite time mode ±1.0% of the set value or ±20 ms
4.1.8

Loss of load supervision LOFLPTUC (ANSI 37)

4.1.8.1 Identification
Function description
Loss of load supervision
4.1.8.2 Function block
Figure 233: Function block
4.1.8.3 Functionality
The loss of load supervision function LOFLPTUC is used to detect a sudden load
loss which is considered as a fault condition.
LOFLPTUC starts when the current is less than the set limit. It operates with the
definite time (DT) characteristics, which means that the function operates after a
predefined operate time and resets when the fault current disappears.
The function contains a blocking functionality. It is possible to block function
outputs, the definite timer or the function itself.
4.1.8.4 Analog channel configuration
LOFLPTUC has one analog group input which must be properly configured.
Table 459: Analog inputs
Input
I3P
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
402
See the preprocessing function blocks in this document for the possible
signal sources.
Value
<35 ms
IEC 61850 IEC 60617
identification identification
LOFLPTUC 3I<
Description
Three-phase currents
1MRS759142 F
ANSI/IEEE C37.2
device number
37
REX640
Technical Manual