ABB Relion 670 Series Applications Manual page 140

Section 8
Current protection
8.3.1 Function revision history
Document
revision
A
B
C
D
E
F
G
H
8.3.2 Identification
Function description
Four step negative sequence
overcurrent protection
8.3.3 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 a 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.
134
Product History
revision
2.2.1 -
2.2.1 -
2.2.2 -
2.2.3 -
2.2.3 -
2.2.3 -
2.2.4 -
2.2.4 Maximum value changed to 2000.0 % of IBase for
settings.
IEC 61850
identification
NS4PTOC
© Copyright 2017 Hitachi Power Grids. All rights reserved
IMin1 , IMin2 , IMin3 and IMin4
IEC 60617 ANSI/IEEE C37.2
identification device number
46I2
I2
4
alt
4
IEC10000053 V1 EN-US
Phasor measurement unit RES670
1MRK 511 407-UUS Rev. J
GUID-FEAFB742-D0DA-4F9E-B4AC-84E568301282 v1
GUID-E1720ADA-7F80-4F2C-82A1-EF2C9EF6A4B4 v1
GUID-343023F8-AFE3-41C2-8440-1779DD7F5621 v2
Application manual