1. OBJECTIVES
Can explain, by an understanding of the fundamentals, the basic operating and maintenance principles of the different types of Transformers and Power Transformers found on an industrial site. It includes the accessories, the electrical protections for the
Power Transformer.
After studying part I, the electrician will be able to:
Explain the fundamental principle of a simple Transformer
Distinguish the different types of Transformers
Describe the operations and principles of protections of a Power Transformer
Explain the choice of a type of Transformer for a specific use
Differentiate the different types of insulation for a Power Transformer
Explain the operation of the different Safety Devices associated with a Power Transformer.
Acknowledge the purpose of maintenance for Power Transformer
Explain the hazards associated with operation and maintenance of Power
Transformer.
At the end part II, the electrician (the same electrician) must be able to carry out the
following for a power transformer:
Differentiate and list the common failures and the possible failures
Explain the different parameters characterising a transformer
Determine and calculate the power of the transformer to be used
Check the operating parameters and analyse the possibilities of malfunctions, particularly overloads
Choose a current transformer and explain its characteristics
Differentiate and list the protective devices on the transformer and the electrical protection systems
Size the protection relays
Understand and apply the maintenance programme
Explain the measurements and analyses performed on the immersion fluid (oil).
Part I - Transformers
2. CONSTRUCTION / THEORY
2.1. INTRODUCTION
2.1.1. History of the Transformer
2.1.2. Physical Elements of a Transformer
2.1.2.1. Magnetic Path:
2.1.2.2. Commonly used magnetic core structures
2.1.2.3. Laminated Silicon Iron (Steel) Core
2.1.2.4. Winding
2.1.3. Practical Consideration.
2.1.3.1. Limitations.
2.1.3.2. Energy Losses .
3. ELECTRICAL DEFINITIONS
3.1. TRANSFORMER AND MAGNET FORMULAE’S
3.1.1. Permeability.
3.1.2. Magnetising Force
3.1.3. Transformer Sequences of operation
3.2. VOLTAGE RATIO
3.2.1. The transformation ratio
3.2.2. The equal turns ratio
3.2.3. Step down transformer .
3.2.4. Step up transformer
3.2.5. Single phase transformer - Polarity
3.3. CURRENT RATIO
3.4. EFFICIENCY.
3.5. EXERCICES
4. THE DIFFERENT TRANSFORMERS.
4.1. CLASSIFICATION.
4.2. AUTOTRANSFORMERS
4.3. POLYPHASE TRANSFORMER..
4.4. RESONANT TRANSFORMER
4.5. INSTRUMENT – CURRENT TRANSFORMERS
4.6. INSTRUMENT – VOLTAGE TRANSFORMERS.
4.7. PULSE TRANSFORMERS .
4.8. ELECTRONIC TRANSFORMERS .
4.8.1. RF Transformers (transmission line transformers)
4.8.2. Baluns ..
