This workshop is designed to update participants with the latest development of Circuit Breakers and to present some of the more common and updated aspects of medium voltage switch gear maintenance. This course describes the essential information that any technician who works in distribution needs to know about CB types, operation and maintenance testing required for all types of MV CB.

Participants in the Circuit breakers & switch gears training course will be able to:

• List the voltage convention classifications used in this course.
• Describe switch gear construction.
• Describe the four basic types of medium voltage circuit breakers.
• How to read MV CB nameplate? And be able to select circuit breaker specification
• Understand the arc phenomena and circuit interruption.
• Know the different types of circuit breakers and industrial switch gears.
• Know the maintenance procedures.
• How to maintain and operate MV circuit breakers.
• Various tests on MV CBs (type/routine/special and field tests)
• Be aware of safe working practices.

This course is recommended for skilled trades, supervisors, and anyone involved in the maintenance of industrial power circuit breakers, especially:

• Maintenance Engineers and supervisors,
• Project Engineers,
• Junior graduated Electrical Engineers.
• Electrical Foreman’s and Technicians
• And in general, Inspection, materials, safety and maintenance Electrical engineering team

Module 1 -General Introduction and Industrial Switch gears

• Key Topics:
• Electrical engineering basic concepts
• Three phase review and per unit
• Voltage levels
• One line and three line diagram
• Generation system layout
• Transmission system layout
• Substation system layout
• Distribution system layout
• Fuses
• Auto-reclosers
• Automatic sectionalize
• Circuit Breakers
• Isolator switches
• Load switches
• Relays
• Current transformers
• Voltage transformers

Module 2 -CB Design Specification Based on Short Circuit Current Level

• Key Topics:
• Faults on power systems
• Transient phenomena in power system.
• Symmetrical component analysis of three phase network
• Network connection for various fault types
• PU system
• Current and voltage distribution in system due to a fault
• Effect of system on zero sequence quantities
• MVA method
• Computer programs based short circuit calculation.

Module 3 - CB Design Specification Based on Arc Phenomena and Circuit Interruption and Safe Operation

• Key Topics:
• Parts of MVCB (charging spring motor, closing coil, trip coil, and anti-pump relay operation, etc).
• Arc phenomena
• Maintenance of the Arc
• Properties of Arc
• Arc Interruption theory
• Circuit Breaker Rating
• Circuit constants and circuit conditions
• Conditions of severity
• Restriking voltage transient
• Circuit breaker mechanisms
• Switching transients
• Duties of Switchgear
• Safety Policies & Electrical Hazards
• Safety rules

• Authorization levels
• Safety documents
• Hazardous associated with electrical equipments
• Electrical hazards & Shock to human
• Arc Flashing hazards (IEEE 1584)
• Incident energy
• Boundary distances
• Labeling
• PPE
• Approved & Standard organizations

Module 4 - Modern MV Vacuum CB and CB

• Key Topics:
• Introduction to CBs
• Advantages of vacuum interruption
• Vacuum contactors and interrupters
• The vacuum medium and the vacuum arc
• Vacuum arc stability
• Vacuum break down
• Vacuum switch construction
• Applications of vacuum circuit breakers
• Basic Features of Breakers
• Dielectric properties of
• Quenching properties of
• Construction of breaker
• SF6 CB types
• Puffer type breakers
• Double Pressure System
• Single Pressure Puffer-Piston System
• Single Pressure Self Blast System
• Improvement in Breakers for HV

Other Type of Circuit Breakers

1. a) Air Circuit Breakers

• Method of increasing arc resistance
• Plan break type
• Magnetic blow out type
• Arc splitter type
• Construction and operation
• Axial air CB
• Blast air CB

1. b) Oil Circuit Breakers

• Arc rupture under oil
• Advantages of oil
• Disadvantages of oil
• Plan break oil circuit breakers
• Arc control circuit oil breakers
• Minimum oil circuit breakers
• Construction and operation

Module 5 -Circuit Breaker Inspection, Maintenance and Services and CB Troubleshooting

• Key Topics:
• Inspection and general inspection technical procedure
• Daily inspection of circuit breakers
• Monthly inspection of circuit breakers
• Annual inspection of circuit breakers
• Disassembly
• Cleaning, tightening and lubrication
• Equipments used in testing
• Testing procedure and direct testing
  Contact resistance test.

• Insulation resistance test
• Test report and indirect testing
• Low insulation Resistance (below 2000 M-„¦) between a) Phase terminal and earthed frame, with breaker closed b) Phase terminals of a pole.
• Resistance between Terminals of Pole too high (above 100 µ) (15 µ per joint) contact
  Unequal contact Wipe and Travel in 3-pole Measured from top surface of interrupter flange and the contact lip by a simple rod with a) breaker open and b) breaker closed
• One of the poles does not close.
• Breaker operation too Slow During opening timing from trip command to contact separation instant too large (60 ms instead of say 40 ms).

Rectus attendance certificate will be issued to all attendees completing minimum of 80% of the total course duration.