After finishing this lesson, you will be able to identify protection relay elements on an electrical drawing according to their ANSI (American National Standards Institute) standard device numbers. In addition, you will be able to describe basic relay operations and compare the accuracy and options provided by commonly used relays.
• Describe the operating principles behind protective relays
• Identify the essential requirements of relay protection
• List the ANSI standard device-function numbers that identify relays
• Describe the two types of electromechanical relays
• Discuss the benefits of solid-state relays