60CTS CT Supervision
Overview of Functions
The 60CTS Current Transformer Supervision function is used to:
•
Detect open circuit current transformer connections on 1 or 2 phases
•
Provide an alarm for indication purposes
Structure of the Function
The CT supervision function element has group dependent settings. These settings can be different in each
settings group – group numbers (Gn) 1 to 4.
The function monitors the primary system current using the 3 phase CT inputs e.g. CT1/2/3. The fundamental
frequency component is measured from processing of the measured current samples.
The 60CTS-V function also monitors the voltage inputs e.g. VT1/2/3.
NOTE
If all 3 input currents fall below the setting, CT failure is not raised.
The function has 2 element types:
•
60CTS-I: CT supervision – current reference
CT and CT wiring connection faults are detected when 1 or 2 of the 3 input currents falls below the CT
supervision current setting for a time in excess of the delay setting.
Outputs are available to indicate the faulted phase.
•
60CTS-V: CT supervision – voltage reference
The presence of negative phase sequence (NPS) current in a power system is normally accompanied by
NPS voltage. The presence NPS current without the corresponding level of NPS voltage a CT or CT wiring
fault.
The 60CTS-V function element operates when the measured negative phase sequence current (I
2
) is
above setting and the measured negative phase sequence voltage (V
2
) is below setting.
6.2
6.2.1
6.2.2
Supervision Functions
6.2 60CTS CT Supervision
374 Reyrolle 7SR5, Overcurrent Protection Device, Device Manual
C53000-G7040-C014-1, Edition 11.2019
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