APP 421: SEL-421 Protection, Automation, and Control System

Course Length: 3 Days (PDHs: 23)
Course Based Fees: $1,500*
* Plus Applicable Tax


APP 421 provides comprehensive application instruction for the SEL-421 Protection, Automation, and Control System. While working directly with an SEL-421, students will gain hands-on experience in communicating with the relay; setting its protection, metering, and monitoring functions; retrieving and reading event reports; and performing control functions.


This course is designed for utility and industrial protection engineers and power system consultants.


Day 1

  • Introduction to the SEL-421
  • Introduction to the Example Protection Scheme
  • Introduction to SEL-421 Relay Communications and acSELerator QuickSet SEL-5030 Software
  • SELogic Control Equations
  • Global Settings
  • Breaker Monitor
  • Line Configuration, Relay Configuration, and Distance Element Settings

Day 2

  • Switch-Onto-Fault, Out-of-Step, and Load-Encroachment Settings
  • Time-Overcurrent Elements
  • Directional Elements
  • Pole-Open Detection
  • Communications-Assisted Tripping Schemes
  • Breaker Failure
  • Synchronism-Check Element
  • Reclosing

Day 3

  • Trip Logic
  • Output Settings
  • Front-Panel Settings
  • Data Capture and Event Reports
  • Communication Protocols
  • Metering
  • Time Synchronization and Synchrophasors

Learning Outcomes

At the conclusion of this course, students can:

  • Apply the SEL-421 relay's protection, monitoring, metering, and control features, including current and voltage selection logic.
  • Use the SELogic control equations with math and comparison variables in the independent protection and automation areas.
  • Apply relay settings, program SELogic control equations, and analyze fault records and relay element responses using QuickSet.
  • Analyze Sequential Events Recorder (SER) reports and use COMTRADE files.
  • Implement relay-to-relay logic via mirrored bits communications.
  • Map and retrieve critical analog and digital information in DNP3 Level 2.
  • Select the appropriate Enable Source Selection (ESS) setting for required applications.
  • Communicate with the relay via the front panel and HMI using its pushbuttons and associated LEDs, display points, target LEDs, and metering screens.

Student Background and Knowledge

Before you attend this class, we recommend that you:

  • Complete CBT 101: Introduction to SEL Relays OR have familiarity with protective relaying, SELogic control equations, QuickSet, front-panel controls, and the SEL-4000 Relay Test System.
  • Have the ability to set up a communications session.

Course Preparation

Install or update the following software/files on the laptop you are bringing to class:

Please ensure that your laptop does not have any installation blocks before you come to class.

Additional information is on the Course Policies and FAQ pages.

Available Courses

Request onsite training for your company.