SEL SEL-421 Protection, Automation, and Control System

SEL-421

Protection, Automation, and Control System

Apply the SEL-421 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 capacitor voltage transformer (CCVT) 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 subcycle operation for application on critical lines requiring high-speed fault clearing.

Transform the way you modernize your substation with optional Time-Domain Link (TiDL) technology or Sampled Values (SV)-based technology using IEC 61850-9-2 or IEC 61869-9.

Complete Subcycle Line Protection

Apply the SEL-421 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.

Bay Control for Two Breakers

SEL-421

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.

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.

Digital Fault Recording (DFR)

Combine relaying reliability with true DFR functionality. The SEL-421 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.

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 improve 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.

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.

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.

SEL TiDL-Based Solutions

Apply a TiDL-based process bus solution, where SEL-TMU devices are placed in the yard close to the primary equipment to digitize discrete I/O signals and analog data.

SEL-TMU units exchange these data with an SEL-421-7 TiDL relay in the control house.

Each SEL-TMU can share data with as many as four TiDL relays, providing protection design flexibility.

TiDL combines the proven protection of the SEL-400 series relays with the purpose-built SEL-TMU, simplifying deployment, reducing training requirements, and increasing availability.

TiDL technology uses point-to-point connections and a non-Ethernet protocol, providing a simple and secure solution.

TiDL also provides built-in data synchronization and synchronous sampling, ensuring protection is available in the relay regardless of whether or not an external time signal is available.

SEL SV-Based Solutions

Based on IEC standards, SV-based solutions maximize flexibility and interoperability.

The SEL-421-7 can be ordered as a merging unit to digitize analog signals from primary equipment and send them to compliant relays in the control house.

The SEL-421-7 can also be ordered as a relay to perform protective functions and other control actions based on the SV data streams it subscribes to.

SV Merging Unit—The SEL-421-7 merging unit comes with complete line protection built in. This allows you to have the protection right next to the primary equipment for increased speed and reliability as well as to easily transmit the SV data streams to subscriber relays in the control house for redundant protection.

SV Relay—The SEL-421-7 relay offers complete line protection and can also receive SV data from devices such as the SEL-421-7 merging unit or the SEL-401 Protection, Automation, and Control Merging Unit.

Because all SEL SV devices are compliant with IEC 61850-9-2 and the UCA 61850-9-2LE guideline as well as IEC 61869-9. the SEL-421-7 can be used with primary equipment that generates similar SV streams or with other manufacturers’ compliant units.

Flexible Ethernet Communications

The two-, four-, and five-port Ethernet communications card options enable you to communicate using a variety of protocols, including FTP, HTTP, DNP3. the Precision Time Protocol Version 2 (PTPv2), PRP, Telnet, synchrophasors, and IEC 61850 Edition 2.1.

The TiDL and SV relays can be configured with a five-port Ethernet card supporting PRP, HRS, or failover functionality to increase system availability, as well as the Precision Time Protocol Version 2 (PTPv2) on process bus or station bus ports for time synchronization.

Use network monitoring features in the relay to further improve system availability by actively monitoring each redundant path to detect communications network failures.

The five-port card also features dedicated ports and IP addresses for station bus and engineering access networks to provide selective access control.

All ports support SFP transceivers. Single- and multimode communications options provide increased flexibility.

All ports support 100 Mbps SFP transceivers, and process bus ports also support 1 Gbps SFP transceivers.

Serial Communications

All four independent EIA-232 serial ports support ASCII, Compressed ASCII, Extended Fast Meter, Fast Operate, Fast SER, enhanced SEL Mirrored Bits communications, Ymodem, and DNP3 Level 2 Outstation as well as dial-out, Virtual Terminal, and communications with SEL-2600 series RTD modules.

Simplified Settings Management

Use acSELerator QuickSet SEL-5030 Software to develop relay settings offline and program SELogic control equations.

Configure the TiDL and SV relays using SEL Grid Configurator, a software tool that increases efficiency and improves settings insights.

It features a spreadsheet-style editor, protection visualization, comprehensive reporting, custom filters, and multiple-device settings management.