Transformer Operational Principles, Selection &Amp; Troubleshooting

Day One

Basic Transformer Theory

•  Currents and magnetic fields
• Air core transformer
• The magnetic circuit
•  The B-H curve
• Hysteresis, and eddy current losses
•  Iron or steel core transformer
• Equivalent circuit of an iron core  transformer
• The practical transformer
•  Magnetizing currents and harmonics
• Voltage considerations
• Thermal considerations

Power Transformers

•  Rating and classifications
• Short circuit duty
•  Efficiency and losses
• Construction
• Accessory equipment
• Inrush current
• Modern and future developments

Distribution Transformers

• • Construction
  • General transformer design
  • Transformer locations
  •  Transformer losses
  • Performance
  • Transformer loading
  •  Special tests
  •  Protection
  • Economic application

Day Two

Underground Distribution Transformers

•  Vault installations
• Surface operable installations
•  Pad mounted distribution transformers

Dry Type Transformers

• Dry type transformers

Transformer Connections

• •  Polarity of single-phase transformers
  • Angular displacement of three-phase transformers
  • Three-phase transformer connections
  • Advantages and disadvantages of the Y-Y connection
  • The Y-delta and delta-Y connection
  •  The Y-delta grounding bank
  •  Zigzag connections
  • Comparisons of economy
  • Three phase banks using single phase transformers
  •  Transforming two-phase voltages into three-phase voltages
  • The scott-connected connection
  • Autotransformers and three-winding transformers
  • Parallelling of transformers
  • Adjournment

Day Three

Loading Power Transformers

•  Design criteria
•  Nameplate ratings
• Other thermal characteristics
•  Thermal profiles
•  Temperature profiles
• Temperature measurements
• Predicting thermal response
• Load cyclicality
•  Water in transformers under load
• Voltage regulation
•  Loading recommendations

Auxiliary Equipment

• Bushings types, standards, design parameters, and testing
•  Oil preservation systems
• Cooling equipment
• Temperature and oil level gauge

Load Tap Chargers (LTCs)

• • Design and applications of load tap changers
  • Rated characteristics and requirements for load tap changers
  • Selection of load tap changers
  • Maintenance of load tap changers
  • Refurbishment replacement of old LTC types

Day Four

Transformer Selection and Application

•  Most economical transformer for your applicatio

Transformer Protection

• Fuses and relays
• Gas relays
•  Differential protection
• Code requirements

Transformer Installation

• Transformer installation
• Sample transformer acceptance check list

Testing Transformers

• • Standards, and classification of tests
  • Sequence of tests
  •  Voltage ratio and proper connections
  • Insulation condition
  • Dielectric withstand
  • Performance characteristics
  • Other tests
  • Adjournment

Day Five

Maintenance and Troubleshooting

• Sample operating and maintenance instructions
• Preventative maintenance and predictive maintenance
• Gas in oil analysis
•  Water in oil analysis
• Drying techniques
• Oil dielectric tests
• Sample transformer maintenance checklist
• Problem and failure investigations
• Problem analysis after sever operating conditions where no failure is involved
• Failure investigations

Power Transformer Equipment Standards and Processes

• Major standards organizations
• Process for acceptance of American National Standards
• Relevant power transformer standards documents

On-Line Monitoring of Liquid-Immersed Transformers

• •  Benefits
  • On-line monitoring systems
  • On-line monitoring applications
  • Concluding Remarks and Final Adjournment