©2015 Siemens Protection Devices Limited
Chapter 7 Page 23 of 64
Step 1 – Connection of CTs
Remove all interposing CTs from the secondary circuit. Connect all line CT secondary wiring in star.
HV load current =
A
132,000
3
10
45
6
8
.
196
Re-use 300/1A CTs.
LV load current =
A
33,000
3
10
45
6
9
.
747
95
.
0
Re-use 560/0.577A CTs.
Step 2 – Selection of Interposing CT Multiplier Settings
HV Secondary current =
A
00
196.8
66
.
0
3
HV ICT Multiplier = 1/0.66 = 1.54
LV Secondary current =
A
747.9
77
.
0
577
.
0
/
560
LV ICT Multiplier = 1/0.77 = 1.30
Figure 2-13 Summary of ICT Settings
Summary of Contents for 7SR242 Duobias
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