60Cts - 7Sr1705/6; Figure 4-6 Logic Diagram: Ct Supervision Function - Current And Voltage Inputs; Table 4-1 Determination Of Ct Failure - Siemens 7SR17 Rho Manual

Chapter 1) 7SR17 Rho Description Of Operation
4.5.2

60CTS - 7SR1705/6

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.
NPS Current
> Setting
> Setting
The element has a setting for NPS current level Gn 60CTS Inps and a setting for NPS voltage level Gn 60CTS
Vnps If the negative sequence current exceeds its setting while the negative sequence voltage is below its setting
for more than Gn 60CTS Delay then a CT failure output (60CTS) is given.
Operation of the CT supervision elements can be inhibited from:
Inhibit 60CTS
Figure 4-6
Page 60 of 78
NPS Voltage
> Setting
< Setting
Table 4-1 Determination of CT Failure
A binary or virtual input.
Logic Diagram: CT Supervision Function – Current and Voltage Inputs
Decision
System Fault
CT Failure
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