T&D World Magazine

Differential Relay Offers Two-winding Transformer Protection, Monitoring and Control

Cooper Power Systems has designed its full-featured differential relay, the iXP-420, to provide comprehensive two-winding transformer protection, and monitoring and control. The iXP-420 incorporates comprehensive voltage and frequency protective functions.

Design characteristics of the relay specific to transformer applications include selectable transformer winding configuration, selective tripping of both high- and low-side breakers, and breaker health monitoring for both controlled breakers. The iXP-420 also includes a Virtual Test Set event record simulator for easy relay set-up and testing.

Protection features of the iXP-420 include two levels of over-excitation (V/Hz) protection, under- and overvoltage, phase overcurrent for each winding, negative-sequence overcurrent for each winding, and breaker fail-to-trip and fail-to-close indicators for both breakers.

For applications that require custom control logic, or where custom functions need to be added to the relay, the iXP-420 comes with the IDEA Workbench, a graphical software-programming environment that permits users to easily customize the iXP-420.

"The iXP-420 is an extremely versatile relay," said Jack McCall, director, protective relays for Cooper Power Systems. "The flexibility of its software makes it well-suited for any number of other applications, including series and shunt reactor protection, rotating machine protection, multi-feeder load shedding and restoration and bus differential protection."

The IDEA Workbench enables users to rapidly and accurately customize controls by using logic diagram and flowchart constructions methods. No equation-based or command-based logic programming is required.

The IDEA Workbench feature of the iXP-420 allows users to:

  • Create custom control and protection logic using over 400 programming signals and tools, all selectable from drag-off toolboxes.
  • Reassign targets and front panel pushbutton functionality.
  • Monitor and control practically every aspect of the relay's operation.
  • Create custom metering and measurement quantities.
  • Configure communications protocols to match existing SCADA system mappings.
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