SELECTION, OPERATION & TROUBLESHOOTING OF TRANSFORMERS

Objective:

• Understand the fundamental principles and operation of power transformers in electrical networks
• Identify different transformer designs, configurations, and applications
• Calculate transformer turns ratios, terminal voltages, and current values
• Understand transformer terminal markings and single-phase and three-phase wiring configurations, including WYE and DELTA connections
• Perform and interpret electrical tests including insulation resistance, excitation, and power factor testing
• Understand transformer insulating oil testing, maintenance, and diagnostic procedures
• Apply safe and effective transformer maintenance and troubleshooting practices
• Develop practical solutions for specifying, operating, and maintaining transformers in industrial and utility environments
• Avoid costly specification and operational errors through proper transformer selection and core design evaluation
• Improve transformer efficiency, reliability, and economic performance
• Develop accurate transformer specifications for different applications
• Understand both theoretical principles and practical applications of modern power transformers

Content:

Fundamentals and Theory of Transformers

• Introduction to transformers
• Magnetic fields and electromagnetic principles
• Relationship between magnetic and electric fields
• Electromagnetism and electromagnetic induction
• Generation of electrical current
• Three-phase electrical systems
• Worldwide AC voltage and frequency standards
• Understanding per-unit values

Transformer Theory and Principles of Operation

• Purpose and scope of transformers
• Types and applications of transformers
• Magnetic and electrical circuits of transformers
• Transformer winding, current, and voltage ratios
• Laws and principles governing transformer operation
• Transformer equivalent circuits and losses
• Transformer efficiency and factors affecting performance
• Voltage regulation and volts-per-turn relationship
• Importance of volts-per-hertz control

Transformer Construction and Components

• Transformer core materials and configurations
• Different transformer core types
• Transformer winding arrangements
• Bushings and insulation systems
• Transformer tanks and fittings

Transformer Cooling and Performance

• Transformer cooling methods and arrangements
• Gas-insulated transformers
• Comparison of transformer cooling systems
• Temperature monitoring and oil level indicators
• Thermal time constant of power transformers
• Transformer sealing systems
• Oil expansion management
• Silica gel breathers and moisture control

Transformer Performance Characteristics

• Understanding transformer nameplate data
• Transformer parameters and operating characteristics
• Three-phase transformers
• Auto-transformers
• Transformer tap changers
• Parallel operation of transformers
• Maximum efficiency considerations
• Dry-type transformers
• Transformer noise management
• Permissible loading of oil-immersed transformers
• Special transformer applications

Transformer Power Factor and Harmonics

• Understanding power factor fundamentals
• Causes and effects of low power factor
• Power factor assessment and improvement techniques
• Calculating capacitor requirements for compensation
• Transformer reactance and voltage rise
• Understanding harmonics and waveform distortion
• Sources and effects of harmonics
• Third harmonic currents and neutral current problems
• Harmonic filtering techniques
• Active power quality filters
• K-rated transformers

Transformer Protection Systems

• Transformer faults and failure mechanisms
• Differential protection relays
• Biased differential protection
• Restricted earth fault protection
• Overcurrent and overload protection
• Buchholz gas-operated relays
• Sudden pressure relays
• Internal fault detection systems
• Explosion protection systems
• Temperature indicators and monitoring
• Tank earth protection

Transformer Testing and Diagnostics

Transformer Oil Testing

• Functions and properties of transformer oil
• Transformer oil standards and requirements
• Hydrocarbon compounds in transformer oil
• Moisture-related problems and control methods
• Factors affecting transformer oil quality
• Cellulose insulation degradation
• Oil dielectric strength testing
• Relative water content testing
• Physical and chemical oil analysis
• Dielectric loss angle and resistivity testing
• Power factor testing
• Dissolved Gas Analysis (DGA)
• Oil colour testing
• Transformer oil sampling procedures
• Oil purification and dehydration methods
• Annual insulating oil testing requirements
• Transformer oil ageing processes

Transformer Electrical Testing

• Understanding transformer test data
• Identifying abnormal transformer operating conditions
• Reasons and benefits of transformer testing
• Transformer performance assurance
• Classification of transformer tests
• Winding resistance testing
• Polarity testing
• Transformer ratio testing
• No-load and load loss testing
• Percentage impedance voltage measurement
• Leakage reactance measurement
• Efficiency testing
• Winding insulation resistance testing
• Capacitance and dissipation factor (tan δ) testing
• Short-circuit withstand testing
• Oil pressure testing
• Temperature rise testing
• Impulse testing
• Transformer handling, inspection, and pre-commissioning procedures

Transformer Diagnostics and Maintenance Management

• Transformer safety procedures
• Visual inspection techniques
• Transformer diagnostic methods
• Transformer condition monitoring
• Transformer maintenance management strategies

For Whom:

• Electrical Engineers and Technicians
• Power Utility Engineers and Technical Personnel
• Maintenance Engineers and Supervisors
• Professionals involved in transformer manufacturing, importing, and distribution
• Engineering personnel in power plants, industrial facilities, and petrochemical plants
• Co-generation operators and electrical service managers
• Technical professionals responsible for power transformer operation, maintenance, and reliability