Maintenance of High-Voltage Circuit Breakers

CIRCUIT BREAKER OVERVIEW
* Identify and describe the main components of a typical oil circuit breaker and explain how an arc is extinguished in this type of circuit breaker.
* Describe and discuss the importance of switchgear and the contribution that switchgear makes to housekeeping and personnel safety in an industrial environment.
* List the components in a typical switchgear assembly.
* Describe how the contacts in a typical circuit breaker are closed.
* Describe how the contacts in a typical circuit breaker are opened.
* Describe how a shunt trip can be used to release a latching mechanism and open breaker contacts automatically.

OIL BREAKERS
* Differentiate between air circuit breakers and oil circuit breakers.
* Describe how a solenoid and springs are used to close and open the contacts in a typical oil circuit breaker.

AIR-MAGNETIC BREAKERS
* Identify and describe the main components of a typical air-magnetic circuit breaker and explain how an arc is extinguished in this type of circuit breaker.

VACUUM BREAKERS
* Identify and describe the main components of an interrupter for a typical vacuum circuit breaker and explain how an arc is extinguished in this type of circuit breaker.

SF6 GAS BREAKERS
* Identify and describe the main components of an interrupter for a typical puffer type SF6 gas circuit breaker and explain how an arc is extinguished in this type of circuit breaker.

CIRCUIT PROTECTION
* Describe a typical overcurrent protection system and a typical under-voltage and overvoltage protection system used with high-voltage circuit breakers.
* Discuss at least three common ratings that are found on breaker nameplates.
* Describe a typical overcurrent protection system used with high-voltage circuit breakers.

ROUTINE MAINTENANCE OVERVIEW
* Describe the purpose of maintenance and testing high-voltage breakers.
* Discuss the frequency of maintenance and testing of high-voltage breakers.
* Explain the importance of occasional operation of circuit breakers and switchgear.
* Express necessary safety measures taken during maintenance and testing.

RACKING OUT AIR-MAGNETIC AND VACUUM BREAKERS
* Describe or demonstrate the procedure for electrically isolating an air-magnetic breaker.
* Describe and discuss the procedure identified as racking out a high-voltage breaker.
* Describe or demonstrate how the interior of an empty switchgear cell is prepared for inspection.

INSPECTING AIR-MAGNETIC AND VACUUM BREAKERS
* Describe how to clean and inspect the interior of an empty switchgear cell.
* Describe how to clean and inspect the components of a typical air-magnetic circuit breaker.
* Describe cleaning and inspection tasks specifically associated with vacuum circuit breakers.

PEPARING OIL AND SF6 GAS BREAKERS
* Describe typical procedures for electrically isolating SF6 gas circuit breakers and oil circuit breakers before maintenance is performed.
* Explain why and describe how an oil sample is usually tested before maintenance is performed on an oil circuit breaker.
* Describe safety and environmental concerns associated with the use of SF6 gas.

INSPECTING AND REPAIRING SF6 AND OIL CIRCUIT BREAKERS
* Describe how to disassemble, clean, inspect, and reassemble a typical oil circuit breaker.
* Describe cleaning and inspection tasks typically associated with puffer-type SF6 gas circuit breakers.

PERFORMING ELECTRICAL TESTS
* Identify and describe how to perform some common electrical tests that may be required during routine maintenance of high-voltage circuit breakers.