Four Step Directional Negative Phase Sequence Overcurrent Protection Ns4Ptoc - ABB REC670 Applications Manual

Section 8
Current protection
8.5
8.5.1
8.5.2
174
Step 4
This step normally has non-directional function and a relatively long time delay.
The task for step 4 is to detect and initiate trip for earth faults with large fault
resistance, for example tree faults. Step 4 shall also detect series faults where one
or two poles, of a breaker or other switching device, are open while the other poles
are closed.
Both high resistance earth faults and series faults give zero-sequence current flow
in the network. Such currents give disturbances on telecommunication systems and
current to earth. It is important to clear such faults both concerning personal
security as well as risk of fire.
The current setting for step 4 is often set down to about 100 A (primary 3I
many applications definite time delay in the range 1.2 - 2.0 s is used. In other
applications a current dependent inverse time characteristic is used. This enables a
higher degree of selectivity also for sensitive earth-fault current protection.
Four step directional negative phase sequence
overcurrent protection NS4PTOC
Identification
Function description
Four step negative sequence
overcurrent protection
Application
Four step negative sequence overcurrent protection NS4PTOC is used in several
applications in the power system. Some applications are:
IEC 61850 IEC 60617
identification identification
NS4PTOC
I2
4
alt
4
IEC10000053 V1 EN-US
1MRK 511 401-UEN A
M15282-177 v4
). In
0
GUID-E8CF8AA2-AF54-4FD1-A379-3E55DCA2FA3A v1
GUID-E1720ADA-7F80-4F2C-82A1-EF2C9EF6A4B4 v1
ANSI/IEEE C37.2
device number
46I2
GUID-343023F8-AFE3-41C2-8440-1779DD7F5621 v2
Bay control REC670 2.2 IEC
Application manual