4.1.5
Three-phase voltage-dependent overcurrent protection
PHPVOC
4.1.5.1
Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Three-phase voltage-dependent
overcurrent protection
PHPVOC
3I(U)>
51V
4.1.5.2
Function block
Figure 164: Function block
4.1.5.3
Functionality
The three-phase voltage-dependent overcurrent protection function PHPVOC
is used for single-phase, two-phase or three-phase voltage-dependent time
overcurrent protection of generators against overcurrent and short circuit
conditions.
PHPVOC starts when the input phase current exceeds a limit which is dynamically
calculated based on the measured terminal voltages. The operating characteristics
can be selected to be either inverse definite minimum time IDMT or definite time
DT.
PHPVOC contains a blocking functionality. It is possible to block function outputs,
timers or the function itself, if desired.
4.1.5.4
Operation principle
The function can be enabled and disabled with the
Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of PHPVOC can be described by using a module diagram. All the
modules in the diagram are explained in the next sections.
1MRS757644 H
Protection functions
620 series
Technical Manual
327