Identification; Application - ABB REB670 Applications Manual
Busbar protection 2.1 ansi, relion 670 series
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Also See for REB670:
- Applications manual (554 pages) ,
- Commissioning manual (196 pages) ,
- Operator's manual (116 pages)
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1MRK 505 337-UUS -
7.4.1
7.4.2
Application manual
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.
Choice of time characteristics: There are several types of time characteristics available
such as definite time delay and different types of inverse time characteristics. The
selectivity between different overcurrent protections is normally enabled by co-
IEC 61850
IEC 60617 identification ANSI/IEEE C37.2
identification
NS4PTOC
I2
4
alt
4
IEC10000053 V1 EN
Section 7
Current protection
device number
46I2
191
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