ABB Relion 670 series - Page 275

Parallel line in service
Setting of zones for parallel line application
The distance protection zone reaches vary with the switching state of the parallel line
configuration. Below the configurations and the corresponding formulas for the reach
calculation are given for the most important cases. In these equations, x stands for ratio of
distance to fault and length of the line, and Z stands for the impedance seen by the relay.
Case 1: Parallel line switched-off and earthed at both ends:
ANSI13000255 V1 EN
Figure 131: The parallel line is out of service and earthed
0 1 0
1 0
1
1 (
1
)
3
Nm
N
m
K
Z x Z
K
Z Z Z
Z Z
+
= ×
+
-
-
×
IECEQUATION14011 V1 EN (Equation 171)
Where:
Z
1
is line positive sequence impedance
K
N
is earth compensation factor for single circuit set at the relay given by
equation
Z
0m
is the zero sequence mutual coupling between the faulted and the
parallel line
x is the ratio of distance to fault and length of the line
0 1
1
3
N
Z Z
K
Z
=
-
×
IECEQUATION14005 V1 EN (Equation 172)
K
Z
Z
Nm
m
=
⋅
0
1
3
IEC13000297 V1 EN (Equation 173)
1MRK 506 369-UUS - Section 8
Impedance protection
Line distance protection REL670 2.2 ANSI 269
Application manual