( )
( )
( ) ( )
2 2
0 Im
Im 0
Re Im
X m B
K
B B
×
=
+
EQUATION1428 V2 EN (Equation 136)
Parallel line is out of service and grounded in both ends
Apply the same measures as in the case with a single set of setting parameters. This means
that an underreaching zone must not overreach the end of a protected circuit for the single
phase-to-ground faults.
Set the values of the corresponding zone (zero-sequence resistance and reactance) equal
to:
R
0E
R
0
1
X
m0
2
R
0
2
X
0
2
+
--------------------------
+
è ø
ç ÷
æ ö
×=
EQUATION561 V1 EN (Equation 137)
X
0E
X
0
1
X
m0
2
R
0
2
X
0
2
+
--------------------------
–
è ø
ç ÷
æ ö
×=
EQUATION562 V1 EN (Equation 138)
8.3.3.6 Setting of reach in resistive direction
Set the resistive reach R1 independently for each zone.
Set separately the expected fault resistance for phase-to-phase faults RFPP and for the
phase-to-ground faults RFPE for each zone. For each distance zone, set all remaining
reach setting parameters independently of each other.
The final reach in resistive direction for phase-to-ground fault loop measurement
automatically follows the values of the line-positive and zero-sequence resistance, and at
the end of the protected zone is equal to equation
139.
1
R 2 R1Zx R0Zx RFPEZx
3
IECEQUATION2303 V2 EN (Equation 139)
2X1Zx X0Zx
arctan
2 R1Zx R0Zx
loop
EQUATION2304 V2 EN (Equation 140)
1MRK 506 369-UUS - Section 8
Impedance protection
Line distance protection REL670 2.2 ANSI 245
Application manual