Protection Functions; Three-Phase Current Protection; Three-Phase Non-Directional Overcurrent Protection Phxptoc (Ansi 51P-1, 51P-2, 50P) - ABB RELION REX640 Technical Manual

Protection functions

4 Protection functions
4.1

Three-phase current protection

4.1.1 Three-phase non-directional overcurrent protection
PHxPTOC (ANSI 51P-1, 51P-2, 50P)
4.1.1.1 Identification
Function description
Three-phase non-directional over-
current protection, low stage
Three-phase non-directional over-
current protection, high stage
Three-phase non-directional over-
current protection, instantaneous
stage
4.1.1.2 Function block
Figure 197: Function block
4.1.1.3 Functionality
The three-phase non-directional overcurrent protection function PHxPTOC is used
as one-phase, two-phase or three-phase non-directional overcurrent and short-
circuit protection.
The function starts when the current exceeds the set limit. The operate time
characteristics for low stage PHLPTOC and high stage PHHPTOC can be selected
to be either definite time ( DT) or inverse definite minimum time ( IDMT). The
instantaneous stage PHIPTOC always operates with the DT characteristic.
In the DT mode, the function operates after a predefined operate time and resets
when the fault current disappears. The IDMT mode provides current-dependent
timer characteristics.
326
IEC 61850 IEC 60617
identification identification
PHLPTOC 3I>
PHHPTOC 3I>>
PHIPTOC 3I>>>
1MRS759142 F
ANSI/IEEE C37.2
device number
51P-1
51P-2
50P
REX640
Technical Manual