html{display:none} APP 487B: SEL-487B Bus Differential and Breaker Failure Relay | Schweitzer Engineering Laboratories

APP 487B: SEL-487B Bus Differential and Breaker Failure Relay

Unable to retrieve course information.  Please try again later.

Course Base Fees:


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

Students in the APP 487B course explore implementation of station-wide, low-impedance current differential protection and integrated circuit breaker failure detection using the SEL-487B Bus Differential and Breaker Failure Relay. Single- and three-relay applications for both basic and complex busbar arrangements are covered. Backup overcurrent protection, event recording, automation, and time-synchronization capabilities are discussed. Students will work directly with the SEL‑487B Relay, performing hands-on communications, settings, and testing.

Course topics include:

  • Busbar differential protection
  • Bus coupler configurations and settings
    • Coupler security logic
    • Bus coupler faults and accelerated tripping
  • Advanced zone selection logic and CT requirements
  • Open-phase detection and breaker failure protection
  • Phase, negative-sequence, and zero-sequence voltage supervision
  • Disconnect and breaker status monitoring
  • Multiple event report analysis and high-resolution Sequential Events Recorder (SER) reports
  • Settings management and event analysis using acSELerator QuickSet SEL-5030 Software
  • Direct transfer trip with Mirrored Bits communications


Day 1
  • Relay Overview
  • Front-Panel HMI and Hardware Overview
  • Relay Communications
  • SELogic Control Equations
  • Single-Zone Application Example
  • Alias Settings
  • Global Settings
Day 2
  • Zone Configuration Settings
  • Protection Settings
  • Output Configuration and Settings
  • Front-Panel Settings
  • Event Report Retrieval and Analysis
  • Dual-Zone Application Example
  • Breaker Failure Protection

Course Objectives

At the conclusion of this course, students can:

  • Determine busbar classifications and interpret station diagrams
  • Establish a busbar protection philosophy
  • Describe differential bus protection schemes, principles, and performance standards
  • Determine input information needed for protection zone selection
  • Assign relay inputs using SELogic control equations and alias names
  • Develop settings for different busbar configurations
  • Program front-panel LEDs to indicate latch bit status
  • Access relay status and event history for multiple relays

Request onsite training for your company.

Get Quote

SEL University Training Question



Course Requirements


Before you attend this class, you must meet the following requirements:

  • Completion of CBT 101: Introduction to SEL Relays (highly recommended)
  • OR
  • Basic familiarity with protective relaying, SELogic control equations, acSELerator QuickSet SEL-5030 Software, front-panel controls, and relay testing
  • Ability to operate a personal computer and set up a communications session using HyperTerminal

Course Preparation

Please check the General Course Information page for what you should bring to class. In addition, please make sure that the laptop you bring to class has the following software/features: