Training
APP 787: SEL-787 Transformer Protection Relay
Description
This course provides hands-on application and step-by-step settings guidance for the SEL‑787 Transformer Protection Relay. APP 787 presents simplified calculation methods and recommendations 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.
Audience
APP 787 is intended for utility and industrial protection engineers and power system consultants.
Agenda
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:
- Complete CBT 101: Introduction to SEL Relays OR be familiar with SEL relays.
 - Have a basic understanding of power systems and transformer protection theory.
 
Course Preparation
Install or update the following software/files on the laptop you are bringing to class:
- acSELerator QuickSet SEL-5030 Software (include all device drivers during installation).
 - SEL-C662 USB driver.
 - SEL-787 instruction manual.
 
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.