4.1.2.2 Function block
TRIP
PICKUP
V_C_CA
V1
BLOCK
67-1
V2
V_A_AB
V_B_BC
I_C
I2
I_A
I_B
NON_DIR
ENA_MULT
TRIP
PICKUP
V_C_CA
V1
BLOCK
67-2
V2
V_A_AB
V_B_BC
I_C
I2
I_A
I_B
NON_DIR
ENA_MULT
GUID-E3431A8A-7DA8-41CA-96E9-8F560E5FCC35 V1 EN
Figure 111: Function block
4.1.2.3 Functionality
The three-phase directional overcurrent protection function 67/51P, 67/50P is used as
one-phase, two-phase or three-phase directional overcurrent and short-circuit protection
for feeders.
67/51P, 67/50P picks up when the value of the current exceeds the set limit and directional
criterion is fulfilled. The trip time characteristics for low stage 67/51P and high stage
67/50P can be selected to be either definite time (DT) or inverse definite minimum time
(IDMT).
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.
4.1.2.4 Operation principle
The function can be enabled and disabled with the Operation setting. The corresponding
parameter values are “Enable” and “Disable”.
The operation of 67/51P, 67/50P can be described using a module diagram. All the
modules in the diagram are explained in the next sections.
Section 4 1MAC059074-MB A
Protection functions
232 615 series ANSI
Technical Manual
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