Identification - ABB REL650 Applications Manual

1MRK 506 334-UUS A
7.3
7.3.1
7.3.2
Application manual
Four step phase overcurrent protection 3-phase output
OC4PTOC (51/67)

Identification

Function description
Four step phase overcurrent protection
3-phase output
Application
The Four step phase overcurrent protection 3-phase output OC4PTOC (51_67) is used in
several applications in the power system. Some applications are:
• Short circuit protection of feeders in distribution and subtransmission systems.
Normally these feeders have radial structure.
• Back-up short circuit protection of transmission lines.
• Back-up short circuit protection of power transformers.
• Short circuit protection of different kinds of equipment connected to the power
system such as; shunt capacitor banks, shunt reactors, motors and others.
• Back-up short circuit protection of power generators.
If VT inputs are not available or not connected, setting parameter
DirModeSelx (x = step 1, 2, 3 or 4) shall be left to default value Non-
directionalor set to Disabled.
In many applications several steps with different current pick up levels and time delays are
needed. OC4PTOC (51_67) can have up to four different, individual settable, steps. The
flexibility of each step of OC4PTOC (51_67) is great. The following options are possible:
Non-directional / Directional function: In most applications the non-directional
functionality is used. This is mostly the case when no fault current can be fed from the
protected object itself. In order to achieve both selectivity and fast fault clearance, the
directional function can be necessary.
Choice of delay time characteristics: There are several types of delay time characteristics
available such as definite time delay and different types of inverse time delay
IEC 61850 IEC 60617
identification identification
OC4PTOC
3I>
4
alt
4
TOC-REVA V1 EN
Section 7
Current protection
ANSI/IEEE C37.2
device number
51/67
179