ABB 615 Series ANSI, Technical Manual

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Section 4
Protection functions
615 series ANSI 109
Technical Manual
Section 4 Protection functions
4.1 Current protection
4.1.1 Three-phase non-directional overcurrent protection 51P/50P
4.1.1.1 Identification
4.1.1.2 Function block
Figure 44: Function block
4.1.1.3 Functionality
The three-phase overcurrent protection 51P/50P is used as one-phase, two-phase or
three-phase non-directional overcurrent and short-circuit protection for feeders.
The function picks up when the current exceeds the set limit. The trip time characteristics
for low stage 51P and high stage 50P-1/2 can be selected to be either definite time (DT) or
inverse definite minimum time (IDMT).The instantaneous stage 50P-3 always trips with
the DT characteristic.
In the DT mode, the function trips after a predefined trip time and resets when the fault
current disappears. The IDMT mode provides current-dependent timer characteristics.
The function contains a blocking functionality. It is possible to block function outputs,
timers or the function itself, if desired.
4.1.1.4 Operation principle
The function can be enabled and disabled with the Operation setting. The corresponding
parameter values are Enable and Disable.
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Three-phase non-directional overcurrent
protection - Low stage
PHLPTOC 3I> 51P
Three-phase non-directional overcurrent
protection - High stage
PHHPTOC 3I>> 50P-1/50P-2
Three-phase non-directional overcurrent
protection - Instantaneous stage
PHIPTOC 3I>>> 50P-3