ABB Relion RES670, Applications Manual

Page: 147 / 382

tPRCrvx, tTRCrvx, tCRCrvx : Parameters for user programmable of inverse reset
time characteristic curve. Further description can be found in the technical
reference manual.
8.3 Four step directional negative phase sequence
overcurrent protection NS4PTOC
GUID-E8CF8AA2-AF54-4FD1-A379-3E55DCA2FA3A v1
8.3.1 Identification
GUID-E1720ADA-7F80-4F2C-82A1-EF2C9EF6A4B4 v1
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-US
46I2
8.3.2 Application
GUID-343023F8-AFE3-41C2-8440-1779DD7F5621 v2
Four step negative sequence overcurrent protection NS4PTOC is used in several
applications in the power system. Some applications are:
• Earth-fault and phase-phase short circuit protection of feeders in effectively
earthed distribution and subtransmission systems. Normally these feeders have
radial structure.
• Back-up earth-fault and phase-phase short circuit protection of transmission
lines.
• Sensitive earth-fault protection of transmission lines. NS4PTOC can have
better sensitivity to detect resistive phase-to-earth-faults compared to distance
protection.
• Back-up earth-fault and phase-phase short circuit protection of power
transformers.
• Earth-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 operating levels and time
delays are needed. NS4PTOC can have up to four, individual settable steps. The
flexibility of each step of NS4PTOC 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
1MRK 511 407-UEN C
Section 8
Current protection
Phasor measurement unit RES670 2.2 IEC 141
Application manual