Ct Supervision (60Cts); Figure 5.3-1 Logic Diagram: Ct Supervision Function (60Cts) - Siemens 7SR224 Description & Operation

5.3 CT S
UPERVISION
Normally the presence of negative phase sequence (NPS) current in a power system is accompanied
by NPS voltage. The presence of NPS current without NPS voltage is used to indicate a current
transformer failure.
The element has a setting for NPS current level 60CTS Inps and a setting for NPS voltage level
60CTS Vnps If the negative sequence current exceeds its setting while the negative sequence voltage
is below its setting for more than 60CTS Delay then a CT failure output (60CTS Operated) is given.
Operation of the under/over voltage elements can be inhibited from:
Inhibit 60CTS
60CTS Element
Enabled
Disabled
VL1
60CTS Vnps
NPS
VL2
V2
Filter
VL3
IL1
60CTS Inps
NPS
IL2
I2
Filter
IL3
Figure 5.3-1
©2009 Siemens Protection Devices Limited
(60CTS)
A binary or virtual input.
Inhibit 60CTS
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Logic Diagram: CT Supervision Function (60CTS)
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(1) Description of Operation 7SR224
60CTS Delay
60CTS Operated
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