The SEL-451 is a complete standalone system. It has the speed, power, and flexibility to combine complete substation bay control with high-speed breaker protection in one economical system. You can use the SEL-451 as an integral part of a full substation protection, control, and monitoring solution. It reduces maintenance costs by accurately tracking the breaker operation. By monitoring breaker interruption times and the accumulated breaker duty, the SEL-451 helps you easily determine the need for proactive maintenance. You can integrate information with SCADA or automation systems through a communications processor or directly to the Ethernet port. Optional Time-Domain Link (TiDL) technology and SEL Sampled Values (SV) technology using IEC 61850-9-2 transform the way you modernize your substation.
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Dual Breaker Bay Control—Meet your bay control needs with complete two-breaker control and high-speed breaker failure detection. You can easily control motor-operated switches, capacitor banks, and field I/O from the relay front panel or remotely. Configurable labels enable customization of relay controls to match your application.
Rapid Bay Control Commissioning—Choose among different bus configurations, including single- and dual-busbar, transfer bus, tie-breaker, breaker-and-a-half, ring-bus, double-bus/ double-breaker, and source-transfer configurations. These bus arrangements allow easy status and control of as many as 20 disconnect switches and two breakers.
High-Impedance Fault Detection—Detect high-impedance faults with Arc Sense technology (AST). High-impedance faults are a common result of a downed conductor on surfaces with poor conductivity. With AST, the SEL-451 alarms or trips for faults that produce low fault current and are undetectable with conventional overcurrent relays.
Complete Overcurrent Protection—Customize distribution protection with multiple instantaneous and time-overcurrent elements combined with SELogic control equations. Best Choice Ground Directional Element logic optimizes directional element performance and eliminates the need for many directional settings.
Pad-Mounted Switchgear Protection—Protect pad-mounted switchgear with low-energy analog (LEA) voltage inputs; this helps you save in overall system cost by eliminating the need for amplification electronics between the line sensor and the relay. Having fewer devices also leads to a simpler system, a reduction in labor costs, and the elimination of a possible point of failure.
Breaker Wear Monitoring—Compare published data from the breaker’s manufacturer to the actual interrupted current and number of operations for two breakers, and create alarms accordingly. You can monitor mechanical and electrical interruption time per pole, comparing average and last trip times for maintenance scheduling.
Digital Secondary System Technologies—TiDL and SEL SV technologies for digital secondary systems replace copper with fiber to increase safety, reduce costs associated with using copper, improve reliability, and limit the impact of an electromagnetic pulse. Apply the TiDL-enabled SEL-451 with the SEL-2240 Axion TiDL nodes in the field to provide remote I/O and communicate digitized analog signals over fiber optics. This simple and secure solution is easy to implement, with no external time source or network engineering required. Apply the SEL-451-6 with SV technology to receive IEC 61850-9-2 SV data from a remote merging unit.
Fast Motor Bus Transfer—Preserve process reliability with the SEL-451 multifunction Fast Motor Bus Transfer System, which switches the motor bus to an alternate source before the motor slows down. The Fast Motor Bus Transfer System includes all transfer modes (fast transfer, in-phase transfer, and residual transfer) in one low-cost SEL-451 package. Learn more.
From the front panel, control and view the status of disconnects and breakers, program operator pushbuttons, and configure labels. LEDs with custom alarms help dispatchers and line crews rapidly restore power.
Six current and six voltage analog inputs support complete bay control and protection for dual-breaker applications. Front and rear EIA-232 serial ports and a rear Ethernet port provide communications.
Fiber-optic ports on the 4U chassis allow the relay to receive analog and digital data from remote TiDL nodes. Commissioning is easy with a press of a button. LEDs indicate a valid configuration as well as the connection status to a remote TiDL node on a per-port basis.
Receive digitized current and voltage information from remote merging units. On this 4U chassis, you can select fiber optics, copper, or mixed Ethernet with separate ports for SV data and engineering access. The Ethernet links are self-monitoring.
Transformer Inrush Harmonic Monitoring
Apply the second-, fourth-, and fifth-harmonic elements with individual threshold settings to detect transformer energization and overexcitation conditions. The output from these harmonic detection elements can be used for a variety of functions, including modification of relay settings to improve security and event reporting to make identification of transformer energization events fast and simple.
Built-In Web Server
Access basic relay information on a standard Ethernet network with the built-in web server. You can view relay status, Sequential Events Recorder (SER) information, metering information, and settings with easy access within a local network. The web server access requires a relay password and is limited to read-only viewing of information.
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 good for basic time synchronization throughout a substation.
Maximize the Capability of Substation Equipment
Fully load equipment by monitoring power, including thermal or rolling interval demand as well as peak demand on positive-, negative-, and zero-sequence current. Use the full capacity of the equipment while maintaining SEL quality protection.
Advanced Visualization Tools
The SEL-451 offers a configurable HMI for easy integration into your application or operating standards. HMI tools include custom metering and status displays, direct pushbutton access, critical information alarms in chronological order, a rotating display, and time-stamped SER reports. You can reduce errors by automatically scrolling between one-line bay diagrams, custom metering displays, and alarms.
Bay Control for Two Breakers
Complete two-breaker control and breaker failure complement the versatility of the SEL-451 programmable logic to meet your bay control needs. Easily control motor-operated switches, capacitor banks, and field I/O from the front panel or remotely. Configurable labels make it easy to customize relay controls to match your application.
Improve Operation With IEEE Synchrophasor Data
Give operators critical system information via serial or Ethernet communications. With the SEL-451, you get the required substation protection, monitoring, and control in addition to a built-in phasor measurement unit at each substation. The relay makes control decisions based on voltage, current, or frequency data from other relays. The synchrophasor real-time control (RTC) capability makes this information available for local or system-wide control and automation.
Time-tag binary COMTRADE event reports with real-time accuracy of better than 10 µs. You can view system state information at the time of faults, or with timed triggers, across the entire system. This system state information helps validate system models and improve transfer limits and system stability.
Digital Fault Recording (DFR)
Combine relaying reliability with true DFR functionality. The SEL-451 Relay’s high-speed sampling (8 kHz) and COMTRADE output provide advanced oscillography. The acSELerator QuickSet SEL-5030 Software graphical user interface makes it easy to view harmonic analysis and events.
Integrate Many Substation Devices Into One Powerful System Using the SEL-451
Control cooling fans, motor-operated switches, or other equipment using the processing and I/O of the SEL-451. Hardware options let you expand I/O up to 103 inputs or 68 outputs.
Expanded SELogic Control Equations
Use math and logic combinations of analog and digital values for customized applications, adapt system control based on prefault conditions, and scale analog values and latch momentary inputs for SCADA retrieval.
acSELerator QuickSet Software
Help speed up relay applications by developing relay settings offline, programming SELogic control equations, and analyzing post-fault event reports.
Voltage Sag, Swell, and Interruption (VSSI) Report
Capture power quality data related to voltage disturbances over a long period of time.
Time-Domain Link Technology
Apply a TiDL solution, where Axion TiDL nodes are placed in the yard close to the primary equipment to digitize discrete I/O signals and analog data and then transport them over a fiber-optic cable to the SEL-451 in the control house. This innovative technology uses point-to-point connections and a nonroutable protocol, providing a simple and secure solution. Because it does not need an external time source or Ethernet switches, it is easy to implement with no network engineering required. TiDL combines the proven protection of the SEL-400 series relays with the modularity of the Axion, reducing training requirements and providing a scalable and flexible solution. It also provides built-in time synchronization and synchronous sampling, ensuring protection is available in the relay regardless of whether an external time signal is available.
SEL Sampled Values Technology
Implement an SEL SV solution, where the merging unit (publisher) digitizes analog signals from primary equipment and then transmits them to an SEL-451-6 Relay (subscriber) in the control house via a fiber-based Ethernet network. The system uses precise time synchronization via IRIG-B or PTP. The SEL-451-6 Relay offers the traditional protection available in the SEL-451-5 and can also receive SV data from devices such as the SEL-401 Protection, Automation, and Control Merging Unit or the SEL-421-7 Protection, Automation, and Control System Merging Unit. Because all SEL SV devices are compliant with IEC 61850-9-2 and the UCA 61850-9-2LE guideline, the SEL-451-6 can be used with other manufacturers’ SV-compliant units.