html{display:none} CBT 421: Introduction to SEL-421 Relays | Schweitzer Engineering Laboratories

CBT 421: Introduction to SEL-421 Relays


This course is intended for protection engineers.

CBT 421 is a step-by-step guide to using the protection features of the SEL-421 Protection, Automation, and Control System. The course leads protection engineers through the entire relay implementation process, from applying a protection scheme design to metering verification.

This course is designed as a half-day program but is self-paced.


  • Introduction
  • Front Panel
  • Setting the Relay
  • Programming the Relay
  • Recloser Control
  • Permissive Overreaching Transfer Tripping (POTT)
  • Managing Settings Files
  • Metering Verification
  • Event Reporting
  • Knowledge Check

Course Objectives

At the conclusion of this course, students can:

  • Implement a two-zone, step-distance protection scheme with single-breaker reclosing using acSELerator QuickSet SEL-5030 Software
  • Apply high-speed, permissive tripping
  • Use enhanced SELogic to track Zone 2 distance element operations
  • Diagnose wiring issues based on metering data and verify connections
  • Communicate with the relay via the front-panel and HMI interface, including pushbuttons and associated LEDs, display points, targeting LEDs, and front-panel metering
  • Retrieve and interpret event report data
Course Information

Single-User Training

Course Base Fees: $USD350*

CBT licenses will expire one year from the purchase date. CBT 101 is a lifetime license.

CEUs: 0.4
Average Completion: 4 hours
Available Courses
Single-User Training

SELU Training Question


Course Requirements


Students should have a basic knowledge of power systems.

Course Preparation

Students should have a calculator with basic math functions.

Check the General Course Information page for course preparation details.