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Current Differential Relay

The SEL-587 Current Differential/Overcurrent Relay provides protection for any two-input apparatus, such as transformers, motors, generators, and reactors. Apply it for differential and overcurrent protection and use event reports for quick post-event analysis.

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Two-Winding Differential Protection—Provide current differential protection with programmable single- or dual-slope percentage restraint for two-winding transformers, reactors, generators, large motors, and other two-terminal apparatus. Automatic tap calculations simplify settings.

Comprehensive Overcurrent Protection—Apply individual winding phase, residual, and negative-sequence overcurrent elements to expand beyond basic transformer protection. In addition, backup overcurrent protection provides high-speed operation, even with severe CT saturation, using the SEL Adaptive Overcurrent Element.

Differential Element Supervision—Use second- and fourth-harmonic blocking or restraint along with dc blocking to supervise differential elements during transformer energization conditions. The calculated fifth harmonic can be used to supervise differential element operations during transformer overexcitation events.


Two-Winding Current Differential Protection
Sensitive current differential protection with programmable single- or dual-slope percentage restraint, supervised by the second- and fifth-harmonic elements for secure differential protection on two-winding apparatus. Choose from common or independent harmonic blocking or restraint. Unrestrained differential elements provide fast operation for high-magnitude internal faults. Automatic calculations of relay tap settings simplify application.

Individual Winding Overcurrent Protection
Individual winding phase, residual, and negative-sequence overcurrent elements, including instantaneous, definite-time, and inverse time-overcurrent elements for comprehensive overcurrent protection.

Protection and Control Logic
SELogic control equations with SELogic variables and timers facilitate traditional or advanced protection schemes.

Monitoring and Reporting
Oscillographic event reports (up to ten 15-cycle reports) and metering functions eliminate or reduce external recorder and metering requirements.

Serial Data Communications
Use the serial port for communications with ASCII terminals, local HMI, SCADA, or DCS systems. The SEL-587 comes standard with a front EIA-232 serial port. As an ordering option, select either an EIA-232 or EIA-485 serial port for the rear. Through settings, select and configure the port for SEL ASCII and interleaved SEL Fast binary messages, or Modbus RTU Slave protocol.

acSELerator QuickSet Software
Develop relay settings off-line, program SELogic control equations, and analyze post-fault event reports.

  • Panel-mount or rack-mount hardware package.
  • Connectorized packaging for quick connect/disconnect includes high-current interrupting output contacts.
  • Rear EIA-232 or EIA-485 serial communications port—either port includes a demodulated IRIG-B time-code input.
  • Bracket with mounting hole for FT-1 switch (switch not included) to mount one 500-series relay in a 19-inch rack.
  • Conformal Coating: Protect equipment from harsh environments and airborne contaminants, such as hydrogen sulfide, chlorine, salt, and moisture.

Minimum Software Version

Latest Firmware Versions

There are no firmware versions available for this product.

Product Revision Firmware ID Date Available Serial Number
SEL-587-0 R801 SEL-587-0-R801-Vxb-Z002001-D20220429 5/7/22 ~1221270001
Conventional Terminal Blocks
SEL-587-0 R704 SEL-587-0-R704-Vxb-Z001001-D20090227 2/27/09 2009058001
Plug-In Connectors (Connectorized®)
SEL-587-1 R801 SEL-587-1-R801-Vxb-Z002001-D20220429 5/7/22 ~1221270001
Conventional Terminal Blocks
SEL-587-1 R704 SEL-587-1-R704-Vxb-Z001001-D20090227 3/19/09 2009078001
Plug-In Connectors (Connectorized®)

The Firmware IDs for older versions of the firmware can typically be found in Appendix A of the instruction manual.

Minimum Software Version

587 - Software Tab


acSELerator QuickSet SEL-5030 Software

QuickSet is a tool for engineers and technicians to quickly and easily configure, commission, and manage power system devices. QuickSet includes a Graphical Logic Editor and a device template tool to reduce configuration time and streamline deployment.

Learn more and download on the SEL-5030 software page.

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