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.