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

Course Length: 2 Days (PDHs: 15)
Course Based Fees: $1,000*
* Plus Applicable Tax


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.


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


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

Learning Outcomes

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.

Student Background and Knowledge

Before you attend this class, we recommend that you:

  • Complete CBT 101: Introduction to SEL Relays (highly recommended) OR have basic familiarity with protective relaying, SELogic control equations, QuickSet, front-panel controls, and relay testing.
  • 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.