html{display:none} SEL-351S Protection System | Schweitzer Engineering Laboratories


Protection System

The SEL-351S Protection System offers comprehensive feeder and overcurrent protection perfect for industrial and utility feeder applications. Enhance your quality of service with lower costs and innovative features, like Mirrored Bits communications, IEEE C37.118 synchrophasors, expanded operator controls, and SEL's Best Choice Ground Directional Element logic.

Starting At


Request a Follow-Up



Request a Follow-Up

Complete Distribution System Protection—Apply a comprehensive mix of overcurrent functions for sensitive protection from phase-to-phase and phase-to-ground faults, and achieve fast operation for three-phase faults.

Reclosing Control—Program the relay four-shot autoreclosing function with synchronism and voltage check logic to mimic a variety of reclosing practices. Sequence coordination logic coordinates with downstream reclosers for a complete protection scheme.

Fast Substation Restoration—Commission automatic substation restoration schemes using programmable user interface controls and Mirrored Bits communications in conjunction with the SEL-2100 Logic Processor.

Reliable Breaker Control—Open or close the circuit breaker manually with the optional SafeLock trip/close pushbuttons, which provide direct control of the breaker independent of the relay.

  • Integrate and automate substation equipment, even devices from multiple vendors, with IEC 61850 communications protocol.
  • Replace older electromechanical relay schemes, control switches, and metering devices in outdoor breaker control enclosures.
  • Commission automatic substation restoration schemes using programmable user interface controls and Mirrored Bits communications.
  • Use the programmable control logic and integration features with a communications link for control and protection of remote substations.
  • Selectively coordinate with downstream SEL-351R Recloser Controls (applied on circuit reclosers) using a Mirrored Bits communications link for secure, high-speed fault clearing on distribution circuits and industrial cogeneration facilities.
  • Dispatch line crews to quickly isolate overhead line problems, and restore service faster using a built-in fault locator, as compared to patrolling the line.
  • Schedule circuit breaker maintenance based on need, as determined from breaker-monitoring data and alarms.
  • Analyze overcurrent protection system performance using built-in Sequential Events Recorder (SER) data.


    1. 1

      USB port simplifies local connections and speeds up relay communications

    2. 2

      Default displays or programmable custom messages notify personnel of power system events or relay status

    3. 3

      Programmable operator pushbuttons and optional user-configurable labels allow for ease of operation

    4. 4

      Front-panel LEDs can be programmed to indicate custom alarms

    5. 5

      Optional SafeLock® trip/close pushbuttons and bright indicating LEDs allow breaker control independent of the relay

    1. 1

      High-current interrupting output contacts increase contact robustness and reliability

    2. 2

      Harmonic metering to the 16th harmonic enhances power quality analysis

    3. 3

      Dual copper Ethernet port allows communication between devices and provides redundancy. Single or dual fiber-optic ports are also available.

    4. 4

      Standard multisession Modbus® TCP, Modbus RTU, DNP3, and IEC 61850 provide communications flexibility

    5. 5

      Mirrored Bits® communications provides fast and reliable relay-to-relay communication

    6. 6

      EIA-485 port provides quick and easy engineering access

    7. 7

      SafeLock® trip/close pushbuttons on the front panel are wired directly to these terminals to allow breaker control independent of the relay

    8. 8

      Expanded I/O allows for flexible applications

    9. 9

      Sensitive earth fault (SEF) protection accurately detects ground faults with low current values

    10. 10

      Built-in phasor measurement unit allows wide-area power system monitoring



  • IEC 61850 communications protocol.
  • Front-panel USB communications port.
  • SafeLock independent trip/close pushbuttons.
  • Dual copper, single or dual fiber-optic Ethernet ports.
  • EIA-485 serial port.
  • Mirrored Bits communications and load profiling.
  • Additional inputs and standard or high-current interrupting contact outputs.
  • Low-range neutral current input channel for nondirectional sensitive earth fault (SEF) applications.
  • Low-range neutral current channel for directional control for Petersen coil-grounded, high-impedance-grounded, or ungrounded power systems.
  • Power elements and voltage sag/swell/interruption records.
  • User-configurable labels for operator controls and target LEDs.
  • Conformal coating: Protects 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-351S-5 R518-V1 SEL-351S-5-R518-V1-Z107106-D20210917 9/28/21 ~1212710001 or ~3212710001
SEL-351S-6 R518-V1 SEL-351S-6-R518-V1-Z107106-D20210917 9/28/21 ~1212710001 or ~3212710001
SEL-351S-7 R518-V1 SEL-351S-7-R518-V1-Z107106-D20210917 9/28/21 ~1212710001 or ~3212710001

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

Minimum Software Version

Sales Resource Central access is required to view the content in this tab.

Sales Resource Central

3xx Software Tab

Configuration Software

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 QuickSet software page.

acSELerator Architect SEL-5032 Software

Architect allows users to configure and document IEC 61850 systems that include GOOSE, Sampled Values (SV), or Manufacturing Message Specification (MMS) communications. Architect automatically compares SCL files with IEC 61850 requirements to ensure standard compliance.

Learn more and download on the Architect software page.

Automated Data Collection

SEL Data Management and Automation (DMA) Application Suite

Available on the Blueframe platform, DMA applications automatically collect, store, and manage device-specific information like oscillography, Sequence of Events (SOE) data, device settings, and property information. They also provide automated password rotation and streamlined device audits.

Learn more on the DMA software page.

Visualization and Analysis

SEL-5601-2 synchroWAVe Event Software

synchroWAVe Event helps engineers diagnose a protective relay’s behavior during a power system fault. It is a powerful and easy-to-use solution for displaying and analyzing SEL relay event reports and COMTRADE files.

Learn more and download on the synchroWAVe Event software page.

Product Certifications