This application guide explains how to set phase angle compensation settings in SEL transformer protection relays for various transformer installations. 

Selecting Transformer Compensation Settings for the SEL-387, SEL-487E, and SEL-787 Relays

This paper discusses the protection of transformers with dual breaker terminals. It covers the compromises that often must be made between security and sensitivity of protection for this common configuration. The paper describes methods for designing transformer protection schemes and presents guidelines for selecting CT ratios and setting restrained and unrestrained differential elements for these applications. 

Application Considerations for Protecting Transformers With Dual Breaker Terminals


This white paper addresses the design considerations for modifying transformer protection at an existing nuclear station and the SEL equipment that can be used to implement that design.


An SEL Approach to Modifying Transformer Protection for Nuclear Stations

This course is designed for utility and industrial protection engineers and power system consultants who want to gain experience communicating, setting, metering, monitoring, retrieving event reports, and performing control functions while working directly with an SEL-487E Relay. This three-day course provides hands-on application and settings guidance for the SEL-487E Transformer Protection Relay, used worldwide to protect and monitor a wide variety of transformers, including power transformers, generator step-up transformers, and autotransformers.

APP 487E: SEL-487E Transformer Protection Relay

Transformer Protection

Transformer protection products and systems provide complete protection for dry-type and oil-filled transformers. They are suited for use in industrial- and commercial-scale facilities.

Transformer Protection

Transformer Protection Relays

Differential Protection Relays

System Components