ABB RELION REB500 Technical Manual page 51

1MRK 505 406-UEN B
Load discrimination
The load area defined by the underimpedance parameters
account by starting and measuring characteristics. The distance function can only trip, if the
fault impedance lies within the underimpedance starting characteristic.
IEC19000412 V1 EN-US
Figure 11:
Zero-sequence compensation of the protected line
The magnitude and phase-angle of the zero-sequence compensation factor are set individually
for each zone using parameters
sequence impedance ZL and the zero-sequence impedance Z0L of the line:

k
0
Range: 0 to 8 in steps of 0.01
k Ang
0
Range: -180° to +90° in steps of 0.01
Bay protection functions REB500
Technical manual
SR
Load discrimination
The load impedance area is only formed when the underimpedance starter (UZ)
is in operation. It does not exist when starting is provided by the overcurrent
starter (OC).

( Z Z )
0 L L
1/ 3 x
Z
L
 
arctan ( X X
0 L
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X
S4
S3
S2
S1
Starting
18000010-IEC19000412-1-en.vsdx
k0 and k0Ang . The k0 factors are calculated from the positive-
 
k 1/ 3 x Z ( Z
0 L L
0
 
) / ( R R ) arctan (
L 0 L L
Bay protection functions
RLoad and AngleLoad is taken into
R
) / Z )
L
X / R )
L L
Section 5
45