
8.10
Voltage-restrained time overcurrent protection
VRPVOC (51V)
8.10.1
Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Voltage-restrained time overcurrent
protection
VRPVOC
I>/U<
51V
8.10.2
Functionality
Voltage-restrained time overcurrent protection (VRPVOC, 51V) function is
recommended as a backup protection for generators.
The overcurrent protection feature has a settable current level that can be used either with
definite time or inverse time characteristic. Additionally, it can be voltage controlled/
restrained.
One undervoltage step with definite time characteristic is also available within the
function in order to provide functionality for overcurrent protection with undervoltage
seal-in.
8.10.3
Function block
ANSI10000118-3-en.vsd
VRPVOC (51V)
I3P*
V3P*
BLOCK
BLKOC
BLKUV
TRIP
TROC
27 Trip
PICKUP
PU_OC
27 PU
IMAX
VUmin
ANSI10000118 V3 EN
Figure 125:
VRPVOC (51V) function block
1MRK 502 048-UUS A
Section 8
Current protection
273
Technical manual