APP 87: SEL-387 and SEL-587 Percentage-Restrained Differential Relays

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


APP 87 provides comprehensive application training for the SEL-387 and the SEL‑587 percentage-restrained differential relays, which offer sensitive, high-speed protection for transformer, machine, and bus differential applications. Students (in groups of two) gain hands-on experience in communicating, setting, metering, monitoring, retrieving and analyzing event reports, and performing control functions by working directly with SEL-387 and SEL-587 Relays. Course topics include:

  • Three-phase, dual-slope percentage-restrained differential elements.
  • Tap, phase, and zero-sequence compensation for transformer differential applications.
  • Harmonic restraint or blocking for transformer inrush and overexcitation.
  • Unrestrained differential element.
  • Multiple phase, negative-sequence, and zero-sequence overcurrent elements.
  • Restricted earth fault ground differential.
  • SELogic control equations.


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


Day 1

  • Introduction to Transformer Differential Protection
  • SEL-587 Relay Overview
  • Introduction to SELogic Control Equations
  • Introduction to acSELerator QuickSet SEL-5030 Software and SEL-AMS
  • SEL-587 Differential Settings (includes a class exercise)
  • SEL-587 Differential Element Testing Introduction
  • Hands-On Differential Element Testing
  • SEL-587 Hands-On Analysis

Day 2

  • SEL-387 Relay Overview
  • SEL-387 Front-Panel Targets and Display
  • SEL-387 Hands-On Meter Checks
  • SEL-387 Differential Element Settings (includes a class exercise)
  • SEL-387E Hands-On Differential Elements
  • SEL-387 Hands-On Analysis
  • Introduction to Volts/Hertz Element (includes class exercises)
  • Additional SEL-387E Hands-On Testing

Learning Outcomes

At the conclusion of this course, students can:

  • Explain the application considerations of differential protection.
  • Apply internal or external phase shift and zero-sequence compensation using two different setting methods in both relays.
  • Use SELogic control equations to customize the relay logic to meet your application requirements.
  • Analyze Sequential Events Recorder (SER) reports and generate COMTRADE files from event reports.
  • Explain testing considerations.

Student Background and Knowledge

Before you attend this class, we recommend that you:

  • Complete CBT 101: Introduction to SEL Relays OR have basic familiarity with protective relaying, SELogic control equations, 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.