ABB Relion 670 series, Technical Reference Manual

Page: 432 / 1232

NS4PTOC (4612) can be completely blocked from the binary input BLOCK. The
pickup signals from NS4PTOC (4612) for each stage can be blocked from the binary
input BLKx. The trip signals from NS4PTOC (4612) can be blocked from the binary
input BLKTR.
7.5.2.7 Directional supervision element with integrated directional comparison
function
At least one of the four negative sequence overcurrent steps must be set
as directional in order to enable execution of the directional supervision
element and the integrated directional comparison function.
NS4PTOC (4612) has integrated directional feature. As the operating quantity current
Iop is always used. The polarizing method is determined by the setting
polMethod . The
polarizing quantity can be selected by NS4PTOC (4612) in one of the following two
ways:
• When polMethod = Voltage , VVPol is used as polarizing quantity
• When polMethod = Dual , VTotPol is used as polarizing quantity
The operating and polarizing quantity are then used inside the directional element, as
shown in figure
207 , to determine the direction of the fault.
Section 7
1MRK505222-UUS C
Current protection
426
Technical reference manual