Transformers have become more essential in our modern electronic life since only a very few device work without it. Transformers have gained greater advantage as they can increase or decrease the voltage and current levels, without modifying the frequency.
This course is designed to help students to know about the need of transformers. It provides a detailed note on construction, installation and maintenance of a transformer. This course also describes different types of transformers and various methods involved in testing it.
After completion of this course, students will have an extensive knowledge about the need and benefits of a transformer. Most important of all, they will know how to protect a transformer from damage and how to maintain it.
WHO SHOULD COMPLETE THIS COURSE?
- Electrical engineers
- Electronics engineers
- Power system analysts
- Process Engineers/Operators
- Electric Power Utility engineers
- University Power System educators
- Electricians
- Machine Operators
COURSE OUTLINE
TRANSFORMERS
- Transformer - Introduction
- Problems without transformer
- Benefits of transformers
- Electromagnetic induction
- Dynamically & statically induced EMF
- Induction coefficients
- Electricity & magnetism terms
- Transformer principle
- Permeability
- Magnetizing characteristics & hysteresis loop
- Phasor diagram of transformers
- Transformer rating
- Three - phase transformer
- Transformer losses & efficiency
- Regulation & winding polarity
- Delta-Star & Start-Delta connection
- Star –Star, Delta – Delta and Zig Zag connection
- Double secondary transformers
TRANSFORMER - CONSTRUCTION
- Transformer parts
- Core laminations
- Typical windows construction
- Comparison of flux orientations
- Transformer windings, constructor shapes & concentric windings
- Continuously Transposed Cable CTC)
- Transformer short circuit currents
- Strengthening to withstand short circuit
- Transformer insulation
- Transformer oil requirements & paper aging cooling medium
- IEC designations
- Transformer tanks
- Fittings & accessories
- Transformer tap changer
- On load tap changer & other accessories
TRANSFORMER - TYPES & PROTECTION
- Transformer types
- Dry type transformer
- Transformer K factor
- Pole mounted transformer
- Auto transformer
- Generator transformer
- Station transformer
- Unit auxiliary transformer
- Substation transformer
- Rectifier transformer
- Need for earthing & consequences
- Earthing methods
- Transformer inrush current
- Mismatch of current transformers
- Types of faults
- Fault current values
- Earth, inter-turn faults
- Core faults, tank faults
- Relays for protection
- HV overcurrent
- Differential protection
- Phase and earth fault scheme
- Delta-Star transformer
- Sensitive ground fault protection
- Current transformer requirements
- Protection against high voltage
TRANSFORMER - TESTING
- Transformer testing
- Transformer routing tests
- Verification of polarity and vector group
- Routine tests
- Type tests
- Special tests
- IEC & ANSI for transformers
- Transformer temperature rise
- Tests on parts and oil
- Particles affect dielectric strength
- Life expectancy of transformer
- Furans, DP and % remaining life
TRANSFORMER – INSTALLATION & MAINTENANCE
- Transformer installation
- Indoor & outdoor transformers
- Creepage distance
- Minimizing transformer noise
- Power circuit connections
- Changes in operating conditions
- Transformers at higher altitudes
- Site installation practices
- Pre-commissioning tests at sites
- IR test arrangement & commissioning
- Energisation & recommended settings
- Earthing system
- Touch & step voltage
- Touch voltage limits
- Transferred potential
- High voltage stations with earth grid
- Earthing system design & recommended earthing arrangements
- Transformers in service & inspection
- Moisture in transformers and its effect
- Measurement & removal of moisture content
- Oil & dissolved gas analysis
- Duval triangle
- Confirmation of transformer problems
- Duval triangle method – example
- Why dielectric response measurement
- Conservator & Oil filling
- Load cycles
- Voltage transformer
