Transformer Training - Fundamentals of Testing and Maintenance

Transformer Training

Our 2-Day Transformer Training course will deal with many of the technical and economic issues dealing with transformer asset management.

Our transformer training course discusses how units are used to reduce voltage for various day-to-day electrical applications. More than 50 million electrical distribution transformers are located on utility poles and cement pads across the United States and Canada. Electrical Transformers serve the crucial function of transforming voltage potential to a higher or lower values to meet the appliances and machinery voltage level requirements. Improper use, maintenance and neglect can cause heavy losses to businesses as well as to the environment. This electrical transformer training course introduces basic safe operational and field diagnostics of transformers with the focus on safe operation, testing and maintenance of the distribution transformers normally installed in substations and on poles.

Students will learn Electrical Transformer Basics - transformer design and operation, as well as safe and proper maintenance and testing procedures on power transformers. The course covers transformers used in commercial and industrial power distribution systems, including oil and dry-type units. Larger power transformers used in utility applications are also covered.

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

  • Understand the basic operation of a transformer.
  • Understand turns ratios and calculate terminal voltage and current.
  • Understand terminal markings and various single phase and three phase wiring schemes. (WYE vs DELTA).
  • Understand how to perform a polarity test on a potential transformer.
  • Understand the electrical testing methods performed on transformers such as insulation resistance testing, excitation and power factor testing.
  • Understand the various tests performed on insulating oil.


WHO should attend

Field and shop technicians, field engineers, supervisors and others responsible for the testing and maintenance of power transformers rated 750kVA to 500MVA and 4.16kV to 500kV.


Students receive

  • This Course Includes Our Latest Electrical Transformer Digital Handbook!! (Value $20)
  • $100 Coupon Toward Any Future Electricity Forum Event (Restrictions Apply)
  • 1.4 Continuing Education Unit (CEU) Credits
  • FREE Magazine Subscription (Value $50.00)
  • Course Materials In Paper Format




Part 1. Transformer Design and Construction

Students will be introduced to the different types of single- and three-phase transformer construction, various types of core material, windings layout, connection, tap changers, voltage classifications and transformer applications, with an emphasis on explaining recent innovations in transformer design.


Transformer Construction and Main Parts

  • Sealed Transformer
  • Breathing Transformers
  • Nitrogen Blanket Transformer
  • Dry Transformers


Transformer Core

  • Transformer core
  • Core form and shell form
  • Core loss
  • Exciting current
  • Noise level
  • Structure
  • Core Mechanical Assembly Requirements
  • Special Requirements for Magnetic Core


Transformer Windings

  • Transformer core
  • Core form and shell form
  • Core loss
  • Exciting current
  • Noise level
  • Structure
  • Core Mechanical Assembly Requirements
  • Special Requirements for Magnetic Core


Transformer Insulation

  • Winding conductors
  • Load loss
  • Impedance and voltage drop
  • Winding insulation
  • Cooling structure
  • Short circuit withstand capability
  • Core and coil assembly


Transformer Tank

  • Oil paper insulation system
  • Two functions of insulation fluid
  • Various insulation fluids
  • Factors affecting quality
  • Factors accelerating degradation
  • Paper and pressboard insulation
  • Two functions of solid insulation
  • Factors affecting quality
  • Factors accelerating aging
  • Aging cycle


Oil Preservation Systems

  • Main tank
  • Main tank components
  • Seals, gaskets and valves, bushings


Transformer Bushings

  • Air cell systems
  • Breathing systems
  • Auto-recharging dehydrating breather
  • Oil cooling systems


Tap Changers

  • Voltage class
  • Current ratings
  • Top and bottom terminal connections
  • Mounting flange
  • Test and voltage taps
  • Air side dimensions
  • Oil side dimensions
  • CT pocket length
  • Oil reservoir
  • Many styles and types in use


Components and Accessories

  • LTC
  • ULTC
  • Headboard links


Part 2. Transformer Operation and Application


Transformer Applications and Types

  • Top oil temperature monitoring
  • Devices/Indicators
  • Winding temperature monitoring
  • Liquid level Gauges/Indicators
  • Pressure and vacuum Gauges/Indicators
  • Pressure relief device
  • Gas Detection Relays
  • Alarm and trip functions are equipped and preset


Transformer Operation and Theory

  • Dry type
  • Liquid filled
  • Industrial vs public distribution
  • Potential transformers (PTs)
  • Current transformers (CTs)
  • Control and power supply transformers
  • Auto transformers


Transformer Cooling

  • Load vs no load
  • Transformer losses
  • Hysteresis losses
  • Eddy current losses
  • Copper losses
  • Stray losses
  • Relationship between primary and secondary values
  • Transformer polarity
  • Single phase transformer connections
  • Transformer impedance
  • Transformer ratings
  • Optimum transformer rating


Three-Phase Theory/Transformer Types

  • Transformer cooling techniques and devices


Resistive Loads

  • Transformer configuration
  • Three phase transformer connections
  • Delta connection
  • Wye 'star' (Y) connection
  • Voltage and current in various combinations
  • Transformer terminal markings and identifications


Transformer Failures

  • Inductive loads
  • Capacitive loads
  • Misapplication
  • Vibration
  • High operating temperature
  • Lightning or line surges
  • Overloading
  • Care of control equipment
  • Lack of cleanliness
  • Care of idle or spare equipment
  • Improper lubrication
  • Careless or negligent operation




Installation, Testing and Maintenance


Installation and safety operation 

  • Standards for Transformers
  • Installation & Relocation
  • Transformer Type Tests
  • Transformer Routine Tests
  • Transformer Commissioning Tests
  • Transformer Maintenance: Concepts of preventive & condition based maintenance
  • Case studies
  • Discussion


Transformer failure statistics

  • Connections and Vector groups
  • Safe procedures relating to transformer operation in a utility or industry environment
  • Thermal performance and Loading of Transformers
  • Practical solutions for operating and maintaining power transformers
  • Voltage Adjustment using Off-Load & On-Load Tap Changing
  • Earthing of HV Transformers
  • Transformer failure modes
  • Lightening
  • Internal Faults
  • External Faults
  • Insulation Damage
  • Component Failures
  • Transformer failure statistics
  • How to categorize transformer failure modes


Protection methods

  • Oil temperature Alarm and Trip
  • Winding temperature Alarm and Trip
  • Buchholz relay, Oil Surge relay & Pressure relief relay
  • Surge protection
  • Fuse protection
  • Protective relaying ?V Overcurrent, Earth fault, Differential & Overflux
  • Example of a Power Transformer System Selection and Installation



Both days:
Start: 8:00 a.m.
Coffee Break: 10:00 a.m.
Lunch: 12:00 noon
Restart: 1:15 p.m.
Finish: 4:30 p.m.




On-Site Training Available

We can present this Transformer Training - Fundamentals of Testing and Maintenance Course to your electrical engineering and maintenance staff, on your premises, tailored to your specific equipment and requirements. We are ready to help design this program for you. Click on the link below to request a FREE quotation.

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