Section 4 Protection Functions; Current Protection; Three-Phase Non-Directional Overcurrent Protection 51P/50P; Identification - ABB RELION 620 Series Technical Manual

1MAC504801-IB E
Section 4
4.1
4.1.1
4.1.1.1
4.1.1.2
4.1.1.3
620 series ANSI
Technical Manual
Protection functions

Current protection

Three-phase non-directional overcurrent protection 51P/50P

Identification

Function description
Three-phase non-directional
overcurrent protection, low stage
Three-phase non-directional
overcurrent protection, high stage
Three-phase non-directional
overcurrent protection, instantaneous
stage

Function block

A070553-ANSI V1 EN
Figure 60: Function block

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.
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.
IEC 61850 IEC 60617
identification identification
PHLPTOC 3I>
PHHPTOC 3I>>
PHIPTOC 3I>>>
Section 4
Protection functions
ANSI/IEEE C37.2
device number
51P
50P-1/2
50P-3
139