html{display:none} APP 421: SEL-421 Protection, Automation, and Control System | Schweitzer Engineering Laboratories

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

PDHs: 23

Course Base Fees: $1,500*
* Plus Applicable Tax


Course Information

This is a three-day course.

Course Base Fees: $1,500 USD

APP 421 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. Students (in groups of two) will gain hands-on experience in communicating, setting, metering, monitoring, reading event reports, retrieving event reports, and performing control functions working directly with the SEL-421 Relay.


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

Course Objectives

At the conclusion of this course, students can:

  • Apply the SEL-421 Relay 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 interface, including pushbuttons and associated LEDs, display points, targeting LEDs, and front-panel metering.

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.

Available Courses

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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.