Ct Supervision (60Cts); 60Cts - 7Pg2113/5; 60Cts - 7Pg2114/6; Figure 6.3-1 Logic Diagram: Ct Supervision Function (60Cts) - 7Pg2113/5 - Siemens Solkor 7PG2113 Technical Manual

6.3

CT Supervision (60CTS)

The relay has two methods of detecting a CT failure, depending on the relay model. CT Supervision is only
available in relays with four current inputs.
6.3.1 60CTS – 7PG2113/5
The current from each of the Phase Current Transformers is monitored. If one or two of the three input currents
falls below the CT supervision current setting CTS I for more than 60CTS Delay then a CT failure output (60CTS
Operated) is given. If all three input currents fall below the setting, CT failure is not raised.
Operation of the CT supervision elements can be inhibited from:
Inhibit 60CTS
Figure 6.3-1 Logic Diagram: CT Supervision Function (60CTS) – 7PG2113/5
6.3.2 60CTS – 7PG2114/6
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 CT supervision elements can be inhibited from:
Inhibit 60CTS
©2010 Siemens Protection Devices Limited
A binary or virtual input.
A binary or virtual input.
7PG2113/4/5/6 Solkor Description of Operation
Chapter 1 Page 73 of 80