This course gives the participant the information necessary in helping him prevent premature failure and costly unplanned outages. The participant will learn the oil and electrical test requirements and how to interpret the test data as well as setting up a proper preventative maintenance program.

This course aims are to provide understanding of the basic fundamentals and constructional features of Power Transformers with particular reference to the design, testing, operation and maintenance of transformers in power systems. The course also highlights the necessary safe procedures relating to Transformer Isolations, Energizing and related circuitry. Special emphasis is also placed on the Testing and maintenance of transformers.

Upon completion of this course, the participant should be able to:

1. Explain the basic operation of a transformer as a main component in any electrical network.
2. Determine different shapes and designs of transformers.
3. Discuss turns ratios and calculate terminal voltage and current.
4. Discuss terminal markings and various single phase and three phase wiring schemes. (WYE vs DELTA).
5. Discuss the electrical testing performed on transformers such as insulation resistance testing, excitation and power factor testing.
6. Discuss the various tests performed on insulating oil.
7. Understand Safe and proper maintenance and troubleshooting procedures on power transformer.
8. Learn practical new solutions for specifying, operating and maintaining power transformers in a utility or plant environment
9. Avoid costly errors from specifying the wrong transformer for your application and from failing to recognize the importance of specifying the right core design
10. Examine the possibilities of maximizing efficiency and economic performance of your transformer fleet
11. Determine precise transformer specifications for every application
12. Become familiar with what makes a power transformer tick
13. Gain knowledge of both the underlying principles and practical applications of power transformers in today's competitive world

Engineers and technicians from electricity supply industry - Engineering professionals from companies manufacturing, importing and distributing Power and Distribution Transformers – Engineers and technical personnel in power utilities, co-generation operators, petrochemical plants, service managers of buildings and hospitals. 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 Transformers

• Pre-test and pro-test
• Variety of learning methods
• Lectures
• Case studies and self-questionnaires
• Small group work
• Discussion
• Presentation

INTRODUCTION AND BASICS

• Introduction
• Magnetic field
• Magnetic and electric fields
• Electromagnetism
• Electromagnetic induction
• Generating electrical current
• Three phase system
• Worldwide AC voltages and frequencies
• Per-unit values

TRANSFORMER THEORY

• Purpose
• Scope
• Types of transformers
• Transformer applications
• Magnetic circuit
• Magnetic and electric circuits of a transformer
• Winding, current and voltage ratios
• Laws of transformer
• Principle of operation of a transformer
• Reflected impedance
• Transformer equivalent circuit
• Transformer losses
• Efficiency
• Why is transformer efficiency usually high?
• Regulation
• Transformer's voltage per turns
• Significance of volts per hertz

TRANSFORMER CONSTRUCTION

• Introduction
• Core material
• Core configurations
• Transformer core types
• Transformer windings
• Bushings
• Tank
• Transformer tank fittings

POWER TRANSFORMER COOLING AND SEALING SYSTEMS

• Introduction
• Cooling arrangement
• ONAN type cooling
• ONAF type cooling
• OFAF type cooling
• OFWF type cooling
• Gas insulated transformer
• Comparison
• Temperature gauges
• Oil level gauge
• Thermal time constant of power transformer
• Power transformer sealing systems
• Effect of oil expansion
• Silica gel breather and moisture

TRANSFORMER PERFORMANCE

• Nameplate data
• Transformer parameters
• Three phase transformer
• Auto-transformer
• Transformer tap changer
• Parallel operation
• Maximum efficiency
• Dry type transformer
• Transformer noise
• Permissible loading of oil-immersed transformers
• Special transformers

TRANSFORMER POWER FACTOR AND HARMONICS

• Introduction
• Causes of low power factors
• Known loads power factors
• Annual power factor penalty
• Unfavourable effects of low power factor loads
• Capacitor price simple payback
• Power factor improvement
• Power factor improvement for power transformer
• Transformer reactance
• Capacitor sizes required to compensate the no-load reactive power of transformers
• Voltage rise
• Harmonics
• Waveform
• Useful parameters
• Sources of harmonics
• Problems created by harmonics
• Third harmonics generate large neutral currents
• Third harmonic filter
• Installation of THF in different networks
• Active filter (power quality filter)
• K-rated transformer

TRANSFORMERS PROTECTION

• Transformer faults
• Differential relays
• Biased differential relays
• Restricted earth fault protection
• Over current protection
• Overload protection
• Gas operated (Buchholz) relay
• Sudden pressure relay
• The internal fault detector
• Explosion vents
• Temperature indicator
• Tank earth protection

OIL TESTING

• Definitions
• Functions of transformer oil
• Transformer oil properties
• Transformer oil standards
• Hydrocarbon compounds in transformer oil
• Moisture problems
• Factors affecting transformer oil properties
  • Cellulose degradation
  • Oil dielectric strength test
  • Relative water content test
  • Physical & chemical tests (polar characteristics of oil)
  • Dielectric losses angle & resistivity test (power factor test)
  • Transformer dissolved gas-in-oil analysis (DGA)
  • Oil color test
  • Insulating oil sampling procedure
  • Oil purification and dehydration
  • Yearly insulating oil testing
  • Oil aging
• Preventive maintenance procedures for transformer oil

TRANSFORMER TESTING

• Test data
• Abnormal operating conditions of power transformer
• Reasons for transformer testing
• Transformer performance assurance
• Classification of transformer tests
• Winding resistance test
• Polarity test
• Ratiometer test
• No-load losses test
• Load losses test
• Percentage impedance voltage measurement
• Leakage reactance measurement
• Efficiency test
• Winding insulation resistance test
• Winding insulation capacitance & dissipation factor (tan δ) test
• Sudden short circuit withstand test
• Oil pressure test
• Temperature rise test
• Impulse testing
• Transformer arrival: Handling, Inspection and Pre-Commissioning

TRANSFORMER DIAGNOSTICS AND MONITORING

• Safety
• Visual inspection
• Transformer diagnostics
• Transformer monitoring
• Transformer maintenance management

A RECTUS attendance certificate will be awarded to all participants who complete at least 80% of the total course duration.