The SEL-351A Protection System has built-in Ethernet and IEEE C37.118 synchrophasors, and is the economical solution for overcurrent protection. Easy-to-use feeder protection and innovative features like SEL’s Best Choice Ground Directional Element logic and SELogic control equations provide superior protection on utility and industrial power systems.
Comprehensive Protection—Provide primary or backup overcurrent protection on distribution feeders with sensitive phase, negative-sequence, residual, and neutral overcurrent protection elements.
Relay Access Convenience—Access basic relay information on a standard Ethernet network with the built-in web server. Securely update firmware and view relay status, settings, and other read-only information within a local network.
Protection Scheme Security—Set the bus overcurrent backup relay close to maximum bus load current levels by using load-encroachment logic to increase security in the system.
Fault Location—Estimate fault locations accurately and reduce total costs by eliminating the need for expensive communications channels, special instrument transformers, prefault information, or line crews to travel the distance of the line for visual fault inspection.
Optimized Asset Utilization—Validate system load flow and fault models by using instantaneous voltage angles from IEEE C37.118 synchrophasors. Use system-state measurements to increase stable system loading through reduced margin requirements.
USB port simplifies local connections and speeds up relay communications
Front-panel LEDs alert operators in the substation to faulted phases, the relay’s status, and element operation
Default displays or programmable custom messages notify personnel of power system events or relay status
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
SafeLock® trip/close pushbuttons on the front panel are wired directly to these terminals to allow breaker control independent of the relay; this is an optional feature.
Harmonic metering to the 16th harmonic enhances power quality analysis
Sensitive earth fault (SEF) protection accurately detects ground faults with low current values; this is an optional feature.
Built-in phasor measurement unit allows wide-area power system monitoring
Dual copper Ethernet port allows communication between devices and provides redundancy
Standard multisession Modbus® TCP, Modbus RTU, DNP3, and IEC 61850 provide communications flexibility; this is an optional feature.
EIA-485 port provides quick and easy engineering access