SEL-351 Protection System
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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
- Innovative Directional Element Polarization
Provide directional stability during phase faults with the positive-sequence, voltage-polarized memory of the phase directional element. Best Choice Ground Directional Element system logic ensures secure ground directional element operation for all types of system grounding practices under varying system conditions.
- Frequency Protection
Provide advanced load shedding with six levels of frequency elements and four rate of change of frequency elements, plus under-/overvoltage protection.
- Reclosing Control
Apply four-shot reclosing with sequence coordination, synchronism check, and voltage check.
- Fault Locator
Calculate accurate distance-to-fault measurements using the impedance-based fault locator.
- Second-Harmonic Blocking
Detect transformer energization with the second-harmonic blocking elements. The output from the harmonic detection elements blocks selected tripping elements until inrush conditions subside.
- Fast Dropout Breaker Failure Element
High-speed breaker failure element and native breaker failure logic enhance breaker failure detection.
- IEC 61850 Communications Protocol
Apply optional IEC 61850 communications to the SEL-351 Protection System for guaranteed performance of substation automation and control. Streamline configurations of IEC 61850 enabled relays with acSELerator Architect® SEL-5032 Software.
- Mirrored Bits Communications Technology
Provide fast and reliable relay-to-relay communication for advanced communications-assisted protection, network reconfiguration, pilot protection, and restoration schemes.
- 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.
- Simple Network Time Protocol (SNTP)
Simplify wiring and installation by receiving a time signal over existing Ethernet networks. SNTP makes a good backup to more accurate IRIG-B time synchronization. The 5 ms accuracy is ideal for basic time synchronization throughout a substation.
- 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.
- Enhanced Breaker Monitoring
Inspect reports for the most recent trip and close operating times and average operating times, or gather trending data for up to 128 previous operations. This information allows timely and economical scheduling of breaker maintenance.
- Metering, Power Quality (PQ) Monitoring
With accurate metering, eliminate the need for external meters (MW, MVAR, MWh, MVARh, PF, rms, and instantaneous/peak demand). Harmonic metering to the 16th harmonic simplifies power quality analysis. Optional power quality monitoring records voltage sags, swells, and interruptions.
- Built-In Web Server
Access basic relay information on a standard Ethernet network with the built-in web server. View relay status, Sequential Events Recorder (SER), metering information, and settings for easy access within a local network. Web server access requires a relay password and is limited to read-only viewing of information.
- Integrate and automate substation equipment, even devices from multiple vendors, with IEC 61850 communications protocol.
- Protect and control radial or looped transmission, subtransmission, or distribution circuits.
- Use pilot protection on transmission or subtransmission circuits, including three-terminal lines.
- Apply directional and nondirectional overcurrent protection for transformer/bus-main/bus-tie breaker.
- Protect and control capacitor banks.
- Apply breaker failure protection.
- Control autoreclosing with synchronism and voltage check logic.
- Protect small generators.
- Protect distributed generation interconnections.
- Shed load using underfrequency elements.
- Add fault indicators to distribution protection and reduce fault-finding time by 50 percent.
- Dispatch line crews to quickly isolate overhead line problems and restore service faster using built-in fault locator.
- 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).
- Use SEL-5010 Relay Assistant Software to manage your relay settings.
- Use acSELerator Report Server SEL-5040 Software to automatically gather relay event reports on your PC and manage them with a database.
- Use acSELerator Analytic Assistant SEL-5601 Software to display oscillograms and vector diagrams to analyze event reports.
- IEC 61850 communications protocol
- Front-panel USB communications port
SafeLock independent trip/close pushbuttons
- Dual copper, single or dual fiber-optic Ethernet ports
- Panel-mount or rack-mount hardware package
- Vertical panel-mount (3U) hardware package
- Mirrored Bits communications and load profiling
- Additional I/O board with contact-sensing inputs and standard or high-current interrupting contact outputs
- Sensitive directional power elements
- Voltage sag, swell, and interruption recording
- 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
Conformal coating—Protects equipment from harsh environments and airborne contaminants such as hydrogen sulfide, chlorine, salt, and moisture
SEL provides options to help you efficiently and safely commission and test these relays.
Carry an SEL-2924 Portable BLUETOOTH® Serial Adapter in your toolbox to connect to an EIA-232 port on a relay, controller, or other device. Use the built-in BLUETOOTH wireless capability of a laptop, smartphone, or other device to communicate over 10 meters (32 feet) via a secure wireless link.
The BLUETOOTH® word mark and logos are registered trademarks owned by Bluetooth SIG, Inc., and any use of such marks by SEL is under license.
Install the SEL RxTx BLUETOOTH® Application on an Android™ or BlackBerry® mobile device to communicate with an SEL-2924 or SEL-2925 BLUETOOTH Serial Adapter.
Add a 6-foot or 15-foot SEL-C662 EIA-232 serial port cable to a PC USB Standard-A port to communicate with SEL relays and other devices with EIA-232 serial ports.
Streamline commissioning by using the SEL-4391 Data Courier® to send and retrieve settings, gather event reports, and install enhancements.
SEL University Training
- APP 351: SEL-351 Protection System
This course provides comprehensive application training for the SEL-351 Directional Overcurrent and Reclosing Relay, an extremely flexible protective relay used by utilities worldwide in multiple applications.
- WBT 351: SEL-351 Relay Coordination Techniques
Learn how to apply techniques for coordinating an SEL-351 Directional Overcurrent and Reclosing Relay with upstream and downstream devices. Real world SEL-351 applications provide you an ideal learning environment for practicing step by step settings calculations.
Configurable Label Templates and Instructions
Access drawings via the Online Product Configuration link in the Ordering Information box at the top right of this page (below the product photo).
From the Product Configuration page, configure your product or enter your part number via the Universal Part Number Reverse Lookup. Then download custom .dwg or .pdf files specific to your product.
You may also go directly to the Product Configuration page to make a product selection.