Identification - ABB REC670 Applications Manual

Section 8
Current protection
8.5.1
8.5.2
184

Identification

Function description
Four step negative sequence
overcurrent protection
Application
Four step negative sequence overcurrent protection NS4PTOC (4612) is used in
several applications in the power system. Some applications are:
• Ground-fault and phase-phase short circuit protection of feeders in effectively
grounded distribution and subtransmission systems. Normally these feeders have
radial structure.
• Back-up ground-fault and phase-phase short circuit protection of transmission
lines.
• Sensitive ground-fault protection of transmission lines. NS4PTOC (4612) can
have better sensitivity to detect resistive phase-to-ground-faults compared to
distance protection.
• Back-up ground-fault and phase-phase short circuit protection of power
transformers.
• Ground-fault and phase-phase short circuit protection of different kinds of
equipment connected to the power system such as shunt capacitor banks, shunt
reactors and others.
In many applications several steps with different current pickup levels and time delays
are needed. NS4PTOC (4612) can have up to four, individual settable steps. The
flexibility of each step of NS4PTOC (4612) function is great. The following options
are possible:
Non-directional/Directional function: In some 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. This can be the case for unsymmetrical fault
protection in meshed and effectively grounded transmission systems. The directional
negative sequence overcurrent protection is also well suited to operate in teleprotection
communication schemes, which enables fast clearance of unsymmetrical faults on
transmission lines. The directional function uses the voltage polarizing quantity.
IEC 61850 IEC 60617
identification identification
NS4PTOC
I2
4
alt
4
IEC10000053 V1 EN-US
1MRK 511 401-UUS A
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 ANSI
Application manual