Siemens 7PG21 Solkor Rf - Figure 6 Through Fault, 1000 ohm pilots, Positive half cycle; Figure 7 Through Fault, 1000 ohm pilots, Positive half cycle

7PG21 Solkor Rf Description of Operation
B
C
A
X
Y
W
Z
D
D3
R
a
D4
XY
R
p
+
-
D2
D
-
+
W Z
C
B
A
R
p
Figure 6 Through Fault, 1000 ohm pilots, Positive half cycle.
D4
R
a
D3
YX
R
p
+
-
D1
A
-
+
ZW
B
C
D
R
p
C
B
D
Y
X
Z
W
A
Figure 7 Through Fault, 1000 ohm pilots, Positive half cycle.
At the other limiting condition the pilot resistance is a 1000 ohms loop and the circuit will be as shown in Figure 6
& Figure 7. with 500 ohms in each leg of the pilot circuit and zero padding resistors. As shown in Figure 6 &
Figure 7 the resultant voltage distribution of this maximum pilot arrangement gives identical voltages across the
relay points B-X and C-Y.
©2011 Siemens Protection Devices Limited Chapter 1 Page 8 of 13