The SEL-351 Protection System has built-in Ethernet and IEEE C37.118 synchrophasors, and is ideal for directional overcurrent applications. Optional Mirrored Bits communications and power quality monitoring add flexibility to solutions. The SEL-351 is the protection standard for utility and industrial electrical systems around the world.
Breaker Failure Detection—Detect a failed circuit breaker quickly with built-in fast-reset breaker failure detection elements and logic.
Pilot Protection Schemes—Apply pilot protection on transmission, subtransmission, or distribution circuits, including three-terminal lines with traditional pilot communications equipment or with optional Mirrored Bits communications.
Grounded Power System Protection—Apply sensitive directional overcurrent protection for Petersen Coil grounded, ungrounded, and impedance-grounded power systems.
Service Restoration—Dispatch line crews to quickly isolate overhead line problems and restore service faster using the built-in fault locator.
Enhanced Circuit Breaker Monitoring—Schedule circuit breaker maintenance based on need as determined from detailed breaker monitoring data and alarms.
USB port simplifies local connections and speeds up relay communications
Default displays or programmable custom messages notify personnel of power system events or relay status
Front-panel LEDs alert operators in the substation to faulted phases, the relay’s status, and element operation
Optional SafeLock® trip/close pushbuttons and bright indicating LEDs allow breaker control independent of the relay
High-current interrupting output contacts increase contact robustness and reliability
Expanded I/O allows for flexible applications
Harmonic metering to the 16th harmonic enhances power quality analysis
Dual copper Ethernet port allows communication between devices and provides redundancy. Single or dual fiber-optic ports are also available.
Standard multisession Modbus® TCP, Modbus RTU, DNP3, and IEC 61850* provide communications flexibility
Mirrored Bits® communications provides fast and reliable relay-to-relay communication
EIA-485 port provides quick and easy engineering access
SafeLock® trip/close pushbuttons on the front panel are wired directly to these terminals to allow breaker control independent of the relay
Sensitive earth fault (SEF) protection accurately detects ground faults with low current values
Built-in phasor measurement unit allows wide-area power system monitoring
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The Firmware IDs for older versions of the firmware can typically be found in Appendix A of the instruction manual.