7PG2113/4/5/6 Solkor Applications Guide
⎟
⎠
⎞
⎜
⎝
⎛
=
−
R
X
Tan
1
θ
o
87
=
θ
Ω
=
=
00544
cos
θ
S
S
Z
R
&
Ω
=
=
0876
.
1
sin
θ
S
S
Z
X
(Primary)
R
L
= 0.07765 ohms/km (Primary)
R
L
= 10 x 0.07765 = 0.7765
Ω
(Primary)
X
L
= 0.28978 ohms/km
X
L
= 10 x 0.28978 = j2.8978
Ω
(Primary)
Total impedance for a through fault at the remote busbar =
Z
S
+ Z
L
= (R
S
+ R
L
) + (X
S
+ X
L
)
(0.0544 + 0.7765) + j(1.0876 +2.8978)
Z
F
= 0.8309 + j3.9854 ohms
2
2
X
R
Z
+
=
2
2
9854
.
3
8309
.
0
+
=
Z
Z
F
= 4.071 ohms
Through Fault Current =
4.68kA
4.071
19.05x10
I
3
F
=
=
Through fault current = 4.68kA compared to 17.5kA Busbar fault current due to the effect of the line impedance.
19.05kV
Zs
17.5kA
Z
4.68kA
L
©2010 Siemens Protection Devices Limited
Chapter 7 Page 36 of 49