SEL-421 Protection, Automation, and Control System
Apply the SEL-421 Protection, Automation, and Control System for high-speed distance and directional protection and complete control of a two-breaker bay.
Protect any transmission line using a combination of five zones of phase- and ground-distance and directional overcurrent elements. A graphical user interface system provides logic and application templates for typical line protection schemes. Patented Coupling Capacitance Voltage Transformer (CVT) transient overreach logic enhances the security of Zone 1 distance elements. Best Choice Ground Directional Element® logic optimizes directional element performance and eliminates many directional settings. Optional additional logic prevents Zone 1 overreach on series-compensated lines. Optional incremental components provide ultra-high-speed (subcycle) operation for application on critical lines requiring high-speed fault clearing.
- Complete Subcycle Line Protection
Apply the SEL-421 Relay for single- and three-pole tripping schemes, compensated lines, or uncompensated lines. Protect transmission lines using five zones of phase and ground-distance elements in communications-assisted schemes, with directional overcurrent backup protection. Use optional high-speed elements to achieve subcycle operating time for most fault types and source impedance ratios. - Synchrophasor Measurements
Turn state estimation into state measurement with wide-area measurement of voltage and current phase angles and magnitudes. Improve system stability with high-speed, load-angle measurements. Increase stable loading with analysis of voltage and angular stability. - Bay Control for Two Breakers
Fully integrate complete breaker protection and control for two breakers. Use the reclosing, breaker failure protection, and complete monitoring to integrate protection and bay control for one or two breakers. Use configurable labels to customize relay controls to match your application. - Communications
Download event reports in seconds, instead of minutes, using the optional Ethernet port with Telnet and FTP. Quickly move information with DNP3 LAN/WAN or IEC 61850 protocols. - 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 relay password and is limited to read-only viewing of information. - High-Accuracy Time Stamping
Time-tag binary COMTRADE event reports with real-time accuracy of better than 10 µs. View system state information at time of faults or with timed triggers, across the entire system. Use system state information to validate system models, improve transfer limits, and system stability. Simple Network Time Protocol (SNTP) is capable of 5 ms accuracy over Ethernet, and makes a good backup to more accurate IRIG-B time synchronization. - Digital Fault Recording
Combine relaying reliability with true DFR functionality. The SEL-421 Relay's high-speed sampling (8 kHz) and COMTRADE output provide advanced oscillography. Use the acSELerator QuickSet® SEL-5030 Software graphical user interface for harmonic analysis and easy report generation. - Expanded SELogic® Control Equations
Use math and logic combinations of analog and digital values for customized applications. Adapt system control based on prefault conditions. Scale analog values and latch momentary inputs for SCADA retrieval. acSELerator QuickSet Software
Helps speed relay application by allowing you to develop relay settings off-line, program SELogic control equations, and analyze post-fault event reports.
NOTE: SEL-421 Z010 Customers using acSELerator QuickSet v4.1.30.0 or v4.1.34.0 - Please verify your SITM setting BEFORE and AFTER upgrading to acSELerator QuickSet.v4.2.3.0.
- Apply complete pilot protection for primary and backup, and single- or three-pole tripping schemes on transmission and subtransmission lines.
- Make settings for up to four shots of automatic breaker reclosing for one or two circuit breakers, with synchronism and voltage checks to optimize system restoration.
- Use the built-in fault locator to efficiently dispatch line inspection and repair personnel.
- Operate power systems with maximum stable loading using real-time voltage and current synchrophasors from any SEL-421-0 Relay location.
- Implement breaker failure logic for one or two circuit breakers.
- Schedule as-needed circuit breaker maintenance and send alarms when the breaker monitor detects excess breaker contact wear from the number of operations and magnitude of interrupted current.
- Track average and last circuit breaker operate time. Alarm on slow circuit breaker.
- Alarm for low-voltage conditions on one or two station batteries.
- Simplify the process of configuring the SEL-421 using the new Graphical Logic Editor (GLE) in acSELerator QuickSet® SEL-5030 Software . The GLE allows you to view your SELogic equations graphically so your settings files can be documented for easier validation and commissioning. Convert existing SELogic control equations to easy-to-read diagrams and save diagrams with your QuickSet settings.
- Use SEL-5601 Analytic Assistant Software to display oscillograms and vector diagrams to analyze event reports.
- Rack- or panel-mount, horizontal and vertical hardware packages.
Ethernet connection options for primary and standby connections.
- DNP3 Level 2 Outstation communications protocol.
- One or two additional I/O boards with standard, high-interrupting or high-speed/ high-interrupting outputs.
- User-configurable labels for operator controls and target LEDs.
Conformal Coating—Protect equipment from harsh environments and airborne contaminants such as hydrogen sulfide, chlorine, salt, and moisture.
Learn more about conformal coating.
SEL provides options to help you efficiently and safely commission and test these relays.
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Streamline commissioning by using the SEL-4391 Data Courier® to send and retrieve settings, gather event reports, and install enhancements.
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When access to the back of panels and cabinets is allowed, use a Connectorized® version of this relay for fast installation and testing.
SEL University Training
- APP 421: SEL-421 Protection, Automation, and Control System
This course provides comprehensive application instruction for the SEL-421 Protection, Automation, and Control System, an extremely flexible, high speed relay for dual breaker control applications, used in multiple functions.
- CBT 421: Introduction to SEL-421 Relays
This computer-based course is a step-by-step guide to using the protection features of the SEL-421 Protection, Automation, and Control System. CBT 421 leads protection engineers through the entire relay implementation process, from applying a protection scheme design to metering verification.
- COM 403: IEC 61850 Technology
- IEC 61850 was created to be an internationally standardized method of
communication and integration and to support systems built from
multivendor intelligent electronic devices (IEDs) that are networked to
perform protection, monitoring, automation, metering, and control
functions. In this communications fundamentals course, you will learn
about the components and protocols that make up the IEC 61850 standard.
During this one-day course, you will walk through the IEC 61850 planning
process and identify key network considerations. This course also
provides a concise introduction to the concepts that will be applied in
SYS 403.
- SYS 310: Modern Synchrophasor Visualization, Control, and Analysis
Time-synchronized measurement can improve your system performance and reliability. Using time-synchronized measurements, you can improve local- and wide-area protection and control, state monitoring, power system modeling, and forensic event analysis. In this two-day, hands-on systems course, you will learn, step-by
- SYS 403: Practical IEC 61850 Application
- The international standard IEC 61850 was designed to standardize
communications and integration methods and to support systems built from
multivendor intelligent electronic devices (IEDs) that are networked to
perform protection, monitoring, automation, metering, and control
functions. SYS 403 is designed to be interactive and activity based.
During this course, you will configure and implement a realistic IEC
61850 communications and automation scheme. Each unit of this course
will guide you, step-by-step, through configuring this comprehensive
communications and automation scheme.
- WBT 421: Applying Dual-Breaker Reclosing With the SEL-421 Relay
Receive live instruction from an industry expert and practical, step-by-step tutorials without leaving your office. WBT 421 is a web-delivered workshop designed to teach you how to apply dual breaker reclosing protection with the SEL-421 Relay for ring-bus and breaker-and-a-half transmission line configurations.
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