Advanced Electrical Transformer Training

Field and shop technicians, field engineers, supervisors and others responsible for the testing and maintenance of power transformers rated 750kVA to 500MVA and 4.16kV to 500kV.

Advanced Electrical Transformer Training Course Outline

DAY ONE

Part 1. Construction and Major Elements of Power Transformers

• Major Electrical parts of the Power transformer
• Major Magnetic Parts
• Insolation System
• Voltage Control Tap Changer
• Enclosure Types and Heat Dissipation
• Cooling System
• Internal Protection

Part 2. Power Transformer governing equations and major parameters

• Equivalent Schematic of the transformer
• Equations governing the power transformers
• Inrush and magnetization current
• Phase diagram of the transformer in normal operation
• Phase diagram of a transformer in short circuit condition
• Active and reactive losses in the Transformer
• Power factor and efficiency
• External Characteristic of a Power Transformer
• Main and Leakage Flux circulation in a Power Transformer

Part 3. Transients and Overvoltages

• Voltage distribution inside the Power Transformer
• Connecting and Disconnecting a Power transformer
• Traveler Waves and Resonant effect
• Design Consideration for minimisation of the Transients
• Short Circuit parameters of the Power transformers

Part 4. Special transformers and applications

• Open Delta – connection transformer
• Tertiary Winding Application
• Autotransformers
• Special core design transformers
• Phase Shift Transformers
• Transformers for Power Electronic Loads-K Factor
• Generator Unit Transformer
• Current transformers and applications

Part 5. Calculations

• How to size a Power transformer for a dedicated Application
• Magnetic Circuit Equivalent schematic
• Saturation conditions
• Nameplate of the Power transformer
• Transformer Loss Calculation
• Transients and Sub-transient model of the Power transformer
• Short circuit calculation for a power transformer
• Forces and Mechanical Stress in a Power Transformer
• Heat dissipation Calculation

Quiz 1:
Students will size and specify a Power Transformer for a specific application.

DAY TWO

Part 6. Connection Diagrams

• Type of connection: Y-Y; Y-Delta; Delta –Y
• Vector group of connection
• Z-connection and applications
• Unbalance condition and internal current circulation study for Y; Delta and Z connection

Part 7. Paralleling Power Transformers

• Conditions to parallel Power Transformers
• Special Consideration to minimize current circulation
• Load sharing between the two parallel transformers

Part 8. Overload Capability of the Power Transformers

• Dry Type Power transformers overload capability
• Oil Type Power transformers overload capability
• Optimum Loading Curve for maximum life expectancy

Part 9. Grounding of Power Transformers

• Solid Grounding and Advantages
• Resistive Grounding
• Impedance Grounding
• Monitoring the Grounding System

Part 10. Protection of the Power transformer

• Winding temperature monitoring and trip
• Oil temperature monitoring and trip
• Protection relay and fuse used for Power Transformer
• Typical Protection scheme for Power Transformers
• Insolation Coordination-BIL
• Surge arrestors and Grounding Grid
• Optimum use of protections to prolong the life of the transformer

Part 11. Special considerations for Power transformers

• Type of Nonlinear Loads
• Total Harmonic Distortion Generated by the load
• K-Crest factor of the transformer
• Harmonics Effect On Power Transformer
• Resonance 
• In line Reactors and Filters consideration
• Root cause investigation and failure mode analyses
• Safe operation of the power transformers
• Standards applicable for power transformers
• Example of Selection and Calculation of a Power Transformer for a Distribution System

COURSE TIMETABLE

Both days:
Start: 8:00 a.m.
Coffee Break: 10:00 a.m.
Lunch: 12:00 noon
Restart: 1:15 p.m.
Finish: 4:30 p.m.