SEL-421 High-Speed Line Protection, Automation, and Control System

Products for Protection, Monitoring, Control, Automation, and Metering

SEL-421

High-Speed Line Protection, Automation, and Control System

Protect Transmission Lines With High-Speed Distance and Directional Functions

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.
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.
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.

Rack- or panel-mount, horizontal and vertical hardware packages.
Ethernet connection options for primary and standby connections
- 10/100BASE-T
- 10BASE-FL
- 100BASE-FX
DNP3 Level 2 Slave 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.

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.
Use SEL-5601 Analytic Assistant Software to display oscillograms and vector diagrams to analyze event reports.

SEL provides options to help you efficiently and safely commission and test these relays.
	Streamline commissioning by using the SEL-4391 Data Courier™ to send and retrieve settings, gather event reports, and install enhancements.
	When access to the back of panels and cabinets is allowed, use a Connectorized^® version of this relay for fast installation and testing.
	Improve safety, save time, and reduce costs with SEL-4600 Series Test Blocks and Plugs. Use the SEL recommended standard block and plug configurations for SEL-421 relays.

Budgetary Retail, Quantity 1: $6,930
Fully Optioned Price: $11,535
(Prices displayed are for planning purposes and are subject to change. Contact your SEL sales representative today for a quote on configurations and quantities to meet your needs.)