Introduction:
Power and distribution transformers are essential devices in electricity supply. Their ratings can vary from small size distribution transformers of a few kVA up to very large power transformers of 1000 MVA or more. In terms
of
voltage
ratings transformers can have operating voltages up to several hundreds of kilovolts. They represent a major asset of the power utility and any industrial plant.
Failure of a transformer can be very costly and dangerous for other major equipment and personnel alike. The design and operation of any transformer must fulfill certain requirements in order to withstand the electric, thermal and mechanical stresses during its service life. Tests and maintenance of transformers according to the relevant standards are intended to ensure that a transformer passing them will give trouble-free service for many years under the conditions it is likely to experience after its installation.
Objectives:
At the end of the course participants will able to:
Refresh the knowledge of the basic theory of transformers
Understand the principles of operation of the transformer
Identify the different features of power transformers, distribution transformers
and instrument transformers
Appreciate the principles of transformer design, ratings, windings, core structure and materials, insulation and cooling methods, selection, insulation, and lifetime
Be familiar with construction of the transformer, transformer winding connections
Recognize the effects of transformer load changes and off-load and on-load tap changers
Understand transformer troubleshooting
Who should attend:
Engineers and Technicians from electricity supply industry
Technical Management Professionals and Department Leaders
Engineering Professionals from companies manufacturing and operating power and distribution transformers
Engineers and Technical Personnel in power utilities, petrochemical plants, service professionals of large infrastructure projects.
Participants need no specific requirements
other
than
basic understanding of electricity and magnetism and circuit theory and general knowledge of nature and operation of power and distribution transformers.
Daily Outlines:
Day 1:
Introduction, General Principles and Classification
General Classification of Transformers: Transformer Construction, Core-Type, Shell-Type, Dry-type Transformers, Oil-filled Transformers, Cooling Techniques
Transformer Windings, Interconnection of Windings, Advantages
and Disadvantages of Principal Connections. Tertiary Windings, Autotransformers
Harmonics in Transformers, Parallel Operation of Transformers, Loadings of Transformers in Parallel, Paralleling Requirements, Polarity
Standards for Transformers, Types
and Requirements
Transformer Tapping and Connections
Ability to withstand Short Circuit, Sound Level
Case studies and workshop discussion
Day 2:
Transformer Constructional Details
Transformer Oil, Characteristics, Oil Oxidation, Breakdown Voltage, Water Content, Acidity, Oil Testing, Field Oil Testing, Dissolved Gas Analysis, Treatment and Filtering of Oil
Effect of Oil Expansion, Breathing Action, Buchholz Relay, Explosion Vents
Instrument Transformers
Transformers for Industrial Applications: Electro-chemical, Arc and Induction Furnaces, Rectifier Transformers, High Voltage Testing Transformers, Precipitator Transformers, Dry Type Transformers
Construction And Details, Transformer Cooling, Natural Cooling, Forced Cooling
Case studies and Workshop Discussion
Day 3:
Transformer Operation, Selection, and Maintenance
Distribution Voltage Adjustment, Off-Load Tap Changing, On-Load Tap Changing
Switching of high voltage underground cables supplying Distribution Transformers
Earthing and Over-Current Protection of Distribution Transformers
Transformer Maintenance: Oil p reservation , Deterioration of oil, Breathers, Condition Monitoring, Faults in Transformers, Tapping and Windings
Advanced Transformer Maintenance
Guidelines on how to care for your Distribution Transformer
Case studies and Workshop Discussion
Day 4:
Transformer Connections
Single Phase Circuits
Two-Phase Circuits
Three-Phase Circuits
Transformer Maintenance and Troubleshooting
Insulation Testing
High Potential Testing
Turns Ratio Testing
oPolarity Testing
Power Factor
Excitation Current
DC Winding Resistance
Polarization Recovery
Insulating Fluid Dielectric
Dissolved Gas Analysis
Day 5:
Transformer Protection, and Relaying
Transformer Faults and Troubleshooting
Differential Relaying
Normal Load
External Faults
Internal Faults
Case studies and Workshop Discussion