Substation-Hardened Ethernet
An Ethernet port is included on every SEL-351A Relay. Multiple Ethernet options simplify integration into new or existing Ethernet networks. Enhance reliability and availability by incorporating dual-port Ethernet SEL-351A 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.
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.
Dependable Overcurrent Protection
Six levels of phase, negative-sequence, neutral, and residual overcurrent elements for coordinated protection, along with phase and sequence under- and overvoltage elements to maximize control scheme flexibility.
Enhanced Security
Voltage or load-encroachment control of the four phase time-overcurrent elements for load security.
- Under- / Overfrequency Protection
Up to six steps of accurate frequency elements for multilevel under- and overfrequency trip and control. Reclosing Control
Programmable four-shot recloser with optional synchronism check to match a variety of reclosing practices.
Metering
Accurate metering eliminates the need for external meters (MW, MVAR, MWh, MVARh, PF, instantaneous/peak demand).
Input Voltage Settings
Select line-neutral (wye) or line-line (delta) input ac voltage connections using software setting.