ABB Relion 670 series, Technical Reference Manual

Page: 427 / 1232

Function Range or value Accuracy
Imaginary part of source Z used
for current polarization
(0.50–3000.00)
W
/phase -
Operate time, pickup function 25 ms typically at 0 to 2 x I
set
-
Reset time, pickup function 25 ms typically at 2 to 0 x I
set
-
Critical impulse time 10 ms typically at 0 to 2 x I
set
-
Impulse margin time 15 ms typically -
7.5 Four step directional negative phase sequence
overcurrent protection NS4PTOC (46I2)
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
7.5.1 Introduction
Four step negative sequence overcurrent protection (NS4PTOC, (4612) ) has an inverse
or definite time delay independent for each step separately.
All IEC and ANSI time delayed characteristics are available together with an optional
user defined characteristic.
The directional function is voltage polarized or dual polarized.
NS4PTOC (4612) can be set directional or non-directional independently for each of
the steps.
NS4PTOC (4612) can be used as main protection for unsymmetrical fault; phase-phase
short circuits, phase-phase-ground short circuits and single phase ground faults.
NS4PTOC (4612) can also be used to provide a system back-up for example, in the
case of the primary protection being out of service due to communication or voltage
transformer circuit failure.
Directional operation can be combined together with corresponding communication
logic in permissive or blocking teleprotection scheme. The same logic as for
1MRK505222-UUS C
Section 7
Current protection
421
Technical reference manual