Characteristic
Value
Retardation time
<35 ms
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
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Loss of load supervision
LOFLPTUC
3I<
37
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
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
Protection functions
1MRS759142 F
402
REX640
Technical Manual