Course Objectives.

• Refresh your knowledge of the basic theory of transformers
• Understand the principles of operation of the transformer
• Identify the different features of power transformers, distribution transformers and instrument transformers
• Appreciate the principles of transformer design, ratings, windings, core structure and materials, insulation and cooling methods, insulation and lifetime
• Be familiar with construction of the transformer, transformer winding connections
• Recognize the effects of transformer load changes and off-load and on load tap changers
• Utilize thermal limits and loading guides of transformers
• Analyze transformer failure modes
• Perform transformer maintenance and transformer testing

Course Outline.

Introduction

• General Principles and Classification
• General Classification of Transformers
• Transformer Construction
• Core-Type Shell-Type, Dry-type Transformers
• Oil-filled Transformers

Cooling Techniques

• Transformer Windings
• Interconnection of Windings, Advantages and Disadvantages of Principal Connections.
• Tertiary Windings, Autotransformers
• Harmonics in Transformers, Parallel Operation of Transformers
• Loadings of Transformers in Parallel, Paralleling Requirements, Polarity
• Standards for Transformers, Types and Requirements
• Transformer Tappings and Connections
• Ability to withstand Short Circuit, Sound Level
• Transformer Constructional Details
  • Transformer Oil
  • Characteristics
  • Oil Oxidation
  • Breakdown Voltage
  • Water Content
  •  Acidity
  • Oil Testing
  • Field Oil Testing
  • Dissolved Gas Analysis
  • Treatment and Filtering of Oil

• Effect of Oil Expansion, Breathing Action, Buchholz Relay, Explosion Vents
• Instrument Transformers
• Construction & Details
• Transformer Features and Thermal Performance
• Thermal performance and Cyclic Rating of Transformers. Temperature indicators and alarms
• Transformer Impedance, Electromagnetic Forces
• Transformer Construction: Cores, Assembly
• Transformer Windings Construction: Coil Types, Disc Coils, Cross-over Coils, Concentric Coils, Sandwich Coils, Transpositions
• Transformer Tanks and Radiators, Tank Losses, Paint Treatments
• Transformer Fittings: Lifting Lugs, Undercarriages, Jacking Pads, Tie-Down Lugs, Bleed Pipes, Thermometers
• Transformer Operation and Maintenance
• Distribution Voltage Adjustment, Off-Load Tap Changing, On-Load Tap Changing
• Switching of high voltage underground cables supplying Distribution Transformers
• Earthling and Over-Current Protection of Distribution Transformers
• Transformer Maintenance
• Advanced Transformer Maintenance
• Measurement of impedance voltage short-circuit impedance and load loss
• Measurement of No-load loss and current
• Insulation resistance
• Harmonics testing

• Separate-source power-frequency voltage withstand test
• Induced overvoltage withstand test
• Transformer Type Tests
• Temperature–rise test
• Lightning impulse test
• Sound level
  • Special Tests: Transformer Partial Discharge testing
  • Accuracy and Interpretation of test results and of test reports
  • Guidelines on how to care for your Distribution Transformer
  • Case studies and Workshop Discussion
  • Transformer Testing
  • Transformer Routine Tests
  • Measurement of winding resistance
  • Measurement of voltage ratio

Who Can Benefit?

• For experienced electrical technicians supervisors and engineers involved with the operation  maintenance of transformers

• Engineers and Technical Personnel in power utilities, petrochemical plants, service professionals of large infrastructure projects.