Circuit Breaker Time-Travel Characteristics

Summary

Substation circuit breakers play a crucial role in transmission and distribution systems. They make and break circuits as needed to ensure the reliable delivery of power to customers, and to protect the systems that deliver the power. Because of their key role, circuit breakers are periodically tested to make sure that they work as they are designed to work. One field test that is used to evaluate circuit breaker performance is the time-travel test.

This 29-minute DVD examines the purpose and principles of time-travel testing. It also describes the operating characteristics of a circuit breaker, and explains why each characteristic is important to the proper operation of the breaker.

Training Sessions

Purpose and Principles of Time-Travel Testing – 6 minutes
Briefly states the purpose of circuit breaker time-travel testing. Explains why contact timing is important to the proper operation of a circuit breaker. Describes the basic principles of performing a timing test.

Circuit Breaker Operations – 8 minutes
Defines the trip, the close, and the trip-free circuit breaker operations. Identifies examples of when each operation would be performed. Describes how the breaker mechanisms function for each operation.

Circuit Breaker Time Characteristics – 5 minutes
Defines the following circuit breaker time characteristics: main contact time, resistor contact time, contact synchronization. Briefly explains why each time characteristic is important to the proper operation of a circuit breaker.

Circuit Breaker Travel Characteristics – 9 minutes
Defines the following circuit breaker travel characteristics: stroke, overtravel, total travel, rebound, contact wipe, average velocity. Briefly explains why each travel characteristic is important to the proper operation of a circuit breaker.

Support Materials Available

Student workbook, instructor guide.