Substation-Hardened Ethernet
An Ethernet port is included on every SEL-351 Relay. Multiple Ethernet options simplify integration into new or existing Ethernet networks. Enhance reliability and availability by incorporating dual-port Ethernet SEL-351 Relays in a self-healing ring structure or in a dual-redundant configuration.
Built-In IEEE C37.118 Synchrophasors
Monitor distribution and transmission networks to detect potential cascading voltage collapse before it happens. IEEE C37.118 synchrophasors, at up to 60 messages per second, allow access to system values for wide-area monitoring and control. The IEEE C37.118 standard simplifies communication and data coordination between synchrophasor measurement units.
SafeLock™Trip/Close Pushbuttons
Optional independent trip/close pushbuttons and high-visibility indication provide direct breaker control. Simplify installation and panel wiring with built-in control switches. The SafeLock system keeps pushbuttons secure when not in use and accommodates tag-out procedures.
Innovative Directional Element Polarization
Positive-sequence voltage-polarized phase directional element with memory for directional stability during phase faults. Best Choice Ground Directional Element™ system logic for secure ground directional element operation for all types of system grounding practices under varying system conditions (SEL-351-5, -6, -7).
Complete and Flexible Protection
Multiple phase, negative-sequence, neutral, and residual instantaneous/definite-time overcurrent elements with independent pickup, time dial, curve, and reset emulation settings. Numerous phase and sequence under- and overvoltage elements. Six steps of frequency elements for multilevel under- and overfrequency trip and control.
Modbus, DNP3, and ASCII protocols
Easily integrate into new or existing networks with these popular protocols. SCADA links, local HMI, and dial-in modems can access important relay data.
Enhanced Security on Heavily Loaded Feeders
Load-encroachment logic allows phase overcurrent elements to be set independently of load levels.
Mirrored Bits® Communications Technology Provides fast and reliable relay-to-relay communication for advanced communications-assisted protection, network reconfiguration, pilot protection, and restoration schemes. Learn more.
Reclosing Control
Programmable four-shot breaker autoreclose with synchronism and voltage check logic to match a variety of reclosing practices. Sequence coordination logic to coordinate with downstream reclosers.
Metering, Load Profiling, PQ Monitoring
Accurate metering eliminates the need for external meters (amps, volts, MW, MVAR, MWh, MVARh, PF, instantaneous/peak demand, frequency, dc volts). Optional load profiling periodically records up to 15 quantities for daily, weekly, and monthly trending information. Optional power quality monitoring records voltage sags, swells, and interruptions.
Input Voltage Settings
Select line-neutral (wye) or line-line (delta) input ac voltage connections using software setting.
acSELerator® Software
Helps speed relay application by allowing you to develop relay settings offline, program SELogic® control equations, and analyze post-fault event reports.