ABB Relion 670 series - Four Step Directional Negative Phase Sequence Overcurrent Protection NS4 PTOC (46 I2)

9.5 Four step directional negative phase sequence
overcurrent protection NS4PTOC (46I2)
9.5.1 Identification
Function description IEC 61850
identification
IEC 60617 identification ANSI/IEEE C37.2
device number
Four step negative sequence
overcurrent protection
NS4PTOC
I2
4
4
alt
IEC10000053 V1 EN
46I2
9.5.2 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
Section 9 1MRK 506 369-UUS -
Current protection
522 Line distance protection REL670 2.2 ANSI
Application manual