Advanced Operation and Maintenance of Circuit Breakers and Switchgear

Introduction

Circuit breakers play an important role in the safe distribution of electrical power. The equipment needs to be operated, maintained, and installed in a safe manner securing continuity of supply to consumers. This following are important aspects of the circuit breakers:

• Electric power systems are designed to be as fault-free as possible through appropriate network design, equipment design, proper installation, and on-going maintenance.
• The Circuit breaker and its associated fault detection equipment, protective relaying, is an extremely important device, through its role of clearing short-circuit currents, disconnecting faulty elements from the power network, and thus maintaining the overall integrity of the power network.

• If faults are not controlled they can cause unnecessary loss of electricity service with all of its many ramifications
• The circuit breaker selection and arc extinction methods are of great importance
• Minimizing downtime by a proper and systematic maintenance program
• The course focuses mainly on the operation and maintenance of circuit breakers, with reference to auxiliary equipment incorporated for its reliable and safe operation.
• The importance of preventive maintenance check and servicing of the various types of circuit breakers
• Implementation of safe systems of work and operations
• Co-ordination of maintenance activities and maintaining system safety
• To be able to understand the component functionalities of the gas and vacuum circuit breakers
• Methods of arc extinction for MV HV circuit breakers
• Routine inspections and the functions of the microprocessor component in the circuit breakers

Objectives

By the end of the training, participants will be able to:

• Learn the importance of preventive maintenance check and servicing of the various types of circuit breakers

• Gain detailed information on the implementation of safe systems of work and operations

• Co-ordination of maintenance activities and maintaining system safety

• Understand the component functionalities of the gas and vacuum circuit breakers

• Familiarize with the methods of arc extinction for MV HV circuit breakers

• Familiarize with the routine inspections and the functions of the microprocessor component in the circuit breakers

Training Methodology

This is an interactive course. There will be open question and answer sessions, regular group exercises and activities, videos, case studies, and presentations on best practice. Participants will have the opportunity to share with the facilitator and other participants on what works well and not swell for them, as well as work on issues from their own organizations. The online course is conducted online using MS-Teams/ClickMeeting.

Who Should Attend?

This course is intended for all Electrical Staffs.

Course Outline

Day 1: Introduction - Reasons for Faults - and Classification of Faults

• The distinction between load and fault current
• Sources of short-circuit current
• Introduction to fault calculations
• Balanced and unbalanced faults

Day 2: Overview of Power System Protection

• Measurement - voltage and current transformers
• Protective device characteristics
• Types of protection systems
• The role and importance of the circuit breaker in power systems

Day 3: General Principles of Arc Extinction

• Overview of types of circuit breaker
• Air-Break
• Vacuum
• Gas
• Other related switching devices
• The single-line diagram
• Substation layouts

Air-Break

• Principles of arc extinction
• D.C. circuit breaking
• A.C. circuit breaking
• Contacts and arc initiation
• Arc chutes
• Performance characteristics
• General construction Principles

Vacuum

• History – The early years
• The vacuum arc – An overview
• Current interruption in vacuum
• Methods of keeping the arc diffuse
• Current chopping – general implications
• Vacuum interrupters in series
• Design of vacuum switchgear
• Maintenance and testing requirements

Day 4: SF6 Gas

• Properties of SF6
• Principles of arc extinction
• Features of construction
• Mechanism principles
• Insulation principles
• Gas leak problems
• Specific supervision requirements
• Circuit power factor considerations
• Maintenance and testing requirements

International Standards

• Importance and relevance to specifications
• ANSI and IEEE
• IIEC and IEE

Day 5: Circuit Breakers and Power System

• Circuit breaker failure and the effects on power system operation
• Circuit breaker inspection, testing, and maintenance program
• The Principles of modern substation control systems
• Power circuit breaker maintenance