Course Details

Objective

At the end of the course participants will gain:

• An understanding of the fundamental theory and principles of the operation of power transformers
• An insight into the identification and application of transformers’ types
• An understanding of the power transformers components and their construction
• Knowledge of power transformer protection
• An understanding of power transformers oil and oil tests and interpretation of results
• Knowledge of the most effective power transformer electrical tests
• Skills in how to manage power transformer breakdowns to ensure minimum disruption

Content

COURSE OUTLINES

1. Basic Transformer Theory
   1. Definition of a Transformer
   2. Magnetic Units and Conversion Factors
   3. Currents and Magnetic Fields
   4. Magnetic Induction
   5. Constructing a Simple Transformer
   6. The Magnetic Circuit
   7. The B-H Curve
   8. The B-H Curve and Hysteresis
   9. Magnetizing Currents and Harmonics
   10. Transformer Core Design and Construction
   11. Magnetostriction
   12. Completing the Transformer by Adding a Second Winding
   13. Transformer tap Changers
   14. Reading and Applying Nameplate Information
        
2. Two-Winding Transformer Connections
   1. The Y-Y Connection in Three-Phase Systems
   2. Advantages of the Y-Y Connection
   3. Disadvantages of the Y-Y Connection
   4. The Y-Δ Connection and the Δ-Y Connection
   5. Phase Angle Displacement and Phase Rotation
   6. The Y-Δ Grounding Bank
   7. The Zigzag Connection
   8. Comparisons of Economy of the Different Winding Configurations
   9. Trade-Off Between Steel and Copper in the Design of a Transformer
   10. Connecting Three-Phase Banks Using Single-Phase Transformers
   11. Transforming Three-Phase Voltages into Two-Phase Voltages
   12. The Scott Transformer Connection
   13. Three-Phase Transformer Designs
   14. Standard Terminal Markings for Transformers
        
3. Transformer Impedance and Losses
   1. Leakage Flux and Leakage Reactance
   2. Conductor Losses
   3. No-Load Losses
   4. Magnetizing Reactance
   5. Equivalent Circuit of a Two-Winding Transformer
   6. A Brief Tutorial on Symmetrical Components
   7. Transformer Equivalent Circuits Modeled in Zero Phase Sequence Networks
   8. Series Impedance and Regulation
   9. Matching Transformers for Parallel and Bank Operations
       
4. Transformer Types
   1. Power Transformers
   2. Distribution Transformers
   3. Phase-Shifting Transformers
   4. Rectifier Transformers
   5. Dry-Type Transformers
   6. Instrument Transformers
   7. Step-Voltage Regulators
   8. Constant-Voltage Transformer
   9. Autotransformers and Three-Winding Transformers
      1. Autotransformer Connections
      2. Impedance of an Autotransformer
      3. Limitations of the Autotransformer Connection
      4. Autotransformer Voltages with Short Circuits Applied
      5. Impulse Voltages Applied to Autotransformers
      6. Autotransformer Core and Coil Designs and Terminal Configurations
      7. Advantages and Disadvantages of the Autotransformer Connection
      8. Three-Winding Transformers
      9. Modification of Transformer Laws with Three Windings
      10. Equivalent Circuit of a Three-Winding Transformer
      11. Core and Coil Construction of Three-Winding Transformers
      12. Thermal Capability of Three-Winding Transformers
      13. The Stabilizing Effect of a Δ Tertiary Winding
           
5. Short Circuits, Inrush Currents, and Other Phenomena
   1. Effects of Short Circuits on Transformers
   2. Comparisons of Short-Circuit Currents for Various Faults
   3. Mechanical Forces in Transformers
   4. Forces between Transformer Windings
   5. Short-Circuit Forces in Three-Winding Transformers
   6. Exciting Current Inrush
   7. Tank Overheating from Zero-Sequence Currents
   8. Primary Fuse Misoperations
   9. Ferroresonance
   10. Voltage Surge
        
6. Basic Concepts of Power System Faults and Transformer Protection
   1. The Reasons For Protection
   2. Principles of protection
   3. Disconnection Devices
   4. Protection and system design
   5. Nature of short circuit currents
   6. Sources Of Short Circuits
   7. Transformer Protection
       
7. Condition Monitoring And Diagnostics
   1. Partial Discharge
   2. Insulation Resistance Monitoring
      1. Insulation Resistance Test (IR)
      2. Megger Test
      3. Polarization Index Test
      4. Correction for Winding Temperature
      5. Insulation Contamination
      6. IR Test Connections
      7. Typical IR Testing Program
   3. DC HI-POT TEST
      1. Maximum Allowable Test Voltage
   4. Measuring Insulation Degradation
      1. Capacitive Charging Current
      2. Resistive Leakage Current
      3. Energy Dissipated
   5. Insulation Power Factor
      1. Insulation Power Factor Standards
      2. Power Factor Test Sets
      3. Outage for Scheduled Maintenance
   6. On Line Measuring Partial Discharge Activity For Insulation
   7. On-Line Monitoring Of Transformers
      1. Local Indications
      2. Thermography
      3. PDA - Partial Discharge Analysis
      4. Insulating Oil Properties
      5. Test for Dielectric Strength
      6. Water Content in Oil
      7. Acidity Test (Neutralization Number
      8. Oxidation Inhibitor
      9. Interfacial Tension Test (IFT)
      10. Oil Color
      11. Oil Power Factor Test
   8. Insulating Oil Dissolved Gas Analysis (DGA)
      1. Release of CO2)
      2. Release of Acetylene
      3. DGA Test Report
      4. DGA Trends
      5. Continuous Gas Monitoring
          
8. Maintenance, Testing, Troubleshooting, and Reliability
   1. Good Utility Practices
   2. Preventative Maintenance versus Predictive Maintenance
   3. Factory Tests
   4. Ratio Test
   5. Other Factory Tests
   6. Field Tests
   7. Gas-in-Oil Analysis
   8. Water-in-Oil Analysis
   9. Drying Transformers
   10. Oil Dielectric Test
   11. Reliability Calculations
   12. The Chi-Squared Distribution
   13. The Poisson Distribution

NOTE:
Pre & Post Tests will be conducted
Case Studies, Group Exercises, Group Discussions, Last Day Review & Assessments will be carried out.

Methodology

A highly interactive combination of lectures and discussion sessions will be managed to maximize the amount and quality of information and knowledge transfer. The sessions will start by raising the most relevant questions, and motivate everybody find the right answers. You will also be encouraged to raise your own questions and to share in the development of the right answers using your own analysis and experiences. Tests of multiple-choice type will be made available on daily basis to examine the effectiveness of delivering the course.
Very useful Course Materials will be given.

• 30% Lectures
• 30% Workshops and work presentation
• 20% Group Work& Practical Exercises
• 20% Videos& General Discussions