html{display:none} SEL-551 Overcurrent/Reclosing Relay | Schweitzer Engineering Laboratories


Overcurrent/Reclosing Relay

The SEL-551 Overcurrent/Reclosing Relay replaces the many relays, control switches, and wiring required in traditional distribution substation protection and control panels. The relay also replaces line recloser control packages at a fraction of the cost. 

Typically Ships in 5 Days

Starting At

$840 USD

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Asset Protection—Monitor and protect distribution feeders, distribution buses, transformers, capacitors, or circuit breakers.

Current Transformer (CT) Connection Versatility—Connect the separate neutral-current input to accommodate core-balance CTs, separate neutral CTs, tertiary-winding CTs, or CT ground-residual circuits.

Reclosing Control—Coordinate with downstream reclosers using sequence coordination logic to program up to four reclosing attempts.

Field-Proven Ruggedness—Program SELogic control equation inputs and outputs to meet application needs in multiple environments. A wide operating temperature range (–40° to +85°C) allows installation in a control house or outdoor enclosure.



Comprehensive Overcurrent Protection
The SEL-551 provides phase, negative-sequence, residual ground, and neutral overcurrent protection in a compact package, including a complete set of instantaneous, definite-time, and time-overcurrent elements.

acSELerator QuickSet SEL-5030 Software
QuickSet helps speed up the relay application by allowing you to develop relay settings offline, program SELogic control equations, and analyze post-fault event reports.

Protection and Control Logic
SELogic control equations with SELogic variables and timers allow traditional or advanced protection schemes. Programmable local control elements permit front-panel pushbutton control. Programmable text display points provide enhanced local operator information.

Monitoring and Reporting
The SEL-551 features Instantaneous, peak, and demand metering. The latest twenty 15-cycle oscillographic data event reports and the latest 512 Sequential Events Recorder (SER) records are stored in nonvolatile memory.

ASCII, binary, and Modbus RTU protocols enhance integration capabilities.

  • Panel-mount or rack-mount hardware package.
  • Connectorized packaging includes high-current interrupting output contacts.
  • EIA-232 or EIA-485 serial communications—either port includes a demodulated IRIG-B time-code input.
  • Bracket with mounting hole for FT-1 switch (switch not included) to mount one SEL-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. Learn more about conformal coating.

Minimum QuickSet Version

Minimum QuickSet Version

Product Certifications