Functionality - ABB RELION REX640 Technical Manual

1MRS759142 C
6.9.3
6.9.4
6.9.5
REX640
Technical Manual

Functionality

The current circuit supervision for transformers function CTSRCTF is used for
monitoring the current transformer secondary circuit where a separate reference
current transformer input for comparison is not available or where a separate voltage
channel for calculating or measuring the zero-sequence voltage is not available.
CTSRCTF can be used for detecting the single-phase failure on the current
transformer secondary for protection application involving two or three sets of the
three-phase current transformers.
CTSRCTF detects a fault in the measurement circuit and issues an alarm which can be
used for blocking the protection functions, for example, differential protection, to
avoid unwanted tripping.
CTSRCTF is internally blocked in case of a transformer under no-load condition or if
a current in any one phase exceeds the set maximum limit.
Analog channel configuration
CTSRCTF has three analog group inputs which must be properly configured.
Table 1186: Analog inputs
Input
I3P1
I3P2
1)
I3P3
1) Can be connected to GRPOFF
See the preprocessing function blocks in this document for the
possible signal sources.
Improper analog channel configuration causes a validation error if the analog
channels are not completely configured or they do not match with certain settings. For
troubleshooting, check the contents of this chapter and also the preprocessing blocks
in this document. The configuration can be written to the protection relay once the
mismatch is corrected.
Operation principle
The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of CTSRCTF can be described with a module diagram. All the modules
in the diagram are explained in the next sections.
Supervision functions
Description
Three-phase currents
Three-phase currents
Three-phase currents
Section 6
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