APP 787: SEL-787 Transformer Protection Relay

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


This course provides hands-on application and step-by-step settings guidance for the SEL‑787 Transformer Protection Relay. APP 787 includes applying simplified calculation methods and recommendations and using data from real-world transformers to develop protection settings. Students (in groups of two) will work directly with an SEL-787 Relay to configure system data and determine protection settings.


APP 787 is intended for utility and industrial protection engineers and power system consultants.


Day 1

  • Product Overview
  • Differential (87) Element Settings
  • Commissioning Assistant
  • Relay Logic Settings
  • Through-Fault Event Monitor

Day 2

  • Restricted Earth Fault (REF) Element Settings
  • Overcurrent Elements
  • Overexcitation Volts/Hertz (24C) Element Settings
  • Over- and Undervoltage (59, 27) Protection
  • Frequency (81) Protection Settings
  • Event Report Retrieval and Analysis

Learning Outcomes

At the conclusion of this course, students can:

  • Use acSELerator QuickSet SEL-5030 Software to read and send settings to the relay.
  • Determine system and transformer winding data and configuration settings.
  • Calculate CT compensation, operate and restraint, and harmonic blocking settings.
  • Test high- and low-voltage CT configuration settings using Commissioning Assistant.
  • Determine settings for through-fault element protection and monitoring.
  • Apply effective protection for REF, overexcitation, undervoltage, and underfrequency.
  • Test settings by observing relay operation after current/voltage is applied.

Student Background and Knowledge

Before you attend this class, we recommend that you:

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.