ABB RELION 670 Series Applications Manual page 175

1MRK 505 337-UUS A
StepForSOTF : If this parameter is set on the step 3 pickup signal will be used as current set level. If
set disabled step 2 pickup signal will be used as current set level.
t4U : Time interval when the SOTF function is active after breaker closing. The setting range is
0.000 - 60.000 s in step of 0.001 s. The default setting is 1.000 s.
ActUndrTimeSel : Describes the mode to activate the sensitive undertime function. The function
can be activated by Circuit breaker position (change) or Circuit breaker command.
tUnderTime : Time delay for operation of the sensitive undertime function. The setting range is
0.000 - 60.000 s in step of 0.001 s. The default setting is 0.300 s
7.4 Four step directional negative phase sequence
overcurrent protection NS4PTOC (46I2)
7.4.1 Identification
Function description
Four step negative sequence
overcurrent protection
7.4.2 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
Application manual
IEC 61850 IEC 60617
identification identification
NS4PTOC
I2
4
alt
4
IEC10000053 V1 EN-US
Section 7
Current protection
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
169