ABB RER670 - Page 87

Unrestrained Limit IdUnre
Restrain
Restrain current [%]
(bias current)
Operate
unconditionally
Operate
conditionally
Section 1 Section 2
Section 3
SlopeSection 2
SlopeSection 3
EndSection 1
EndSection2
Operate current [%]
(differential current)
IdMin
IEC15000390-2-en.vsdx
IEC15000390 V2 EN-US
Figure 30: Operate-restrain characteristic
The operate-restrained characteristic is determined by five parameter settings:
• IdMin
• EndSection1
• EndSection2
• SlopeSection2
• SlopeSection3
The slope is relative to the characteristic breakpoint.
%100



BIAS
DIFF
I
I
slope
IECEQUATION15054 V1 EN-US (Equation 3)
1MRK 506 375-UEN A Section 6
Differential protection
Railway application RER670 2.2 IEC 81
Application manual