Installation of high voltage distribution and transmission equipment has increased significantly over the years due to ongoing global demand for power. As a result, the need to ensure the reliability of operation of power systems is paramount. It is critical that all personnel operating and working with such equipment have a sound knowledge of their operational requirements and maintenance.

This course provides knowledge on both the theory and operation of power transformers. The course will develop and enhance an understanding of what is involved in the maintenance of these essential components of power systems, through the tips and tricks learnt and developed by some of the world’s pre-eminent electrical engineers.

YOU WILL GAIN

• An understanding of the fundamental theory and principles of the operation of power transformers and transformer protection
• An insight into the identification and application of transformer types
• An understanding of power transformers, oil and oil tests and interpretation of results
• Skills in how to manage power transformer breakdowns to ensure minimum disruption

WHO SHOULD COMPLETE THIS COURSE

• Consulting engineers
• Electrical contractors and inspectors
• Electrical engineers and technicians
• Power system engineers and technicians
• Project engineers
• Tradesman electricians
• Utility engineers

COURSE OUTLINE

TRANSFORMERS’ MAIN FUNCTIONS AND CLASSIFICATION

• Introduction
• Transformer types - General
• Transformer types
• Dry Type Transformer
• Transformer K Factor
• ANSI Transformer K Factor
• Pole mounted transformer
• Auto Transformer
• Generator Transformer
• Station Factor
• Unit Auxiliary Transformer
• Substation Transformer
• Rectifier Transformer
• Power Transformer
• Type of Cooling
• On Load Tap Changer
• Control Panel
• Control Cable Terminal Box
• Control Cable Terminal Box

TRANSFORMER THEORY

• Introduction to transformer installation
• Alternating Current System
• Magnitude of Voltage
• Inductive Circuit
• Electricity Magnetism
• Magnetic Material
• Electro Magnetic Induction
• Induction Coefficient
• Electricity and Magnetism Terms
• Transformer Principle
• EMF Equation
• Transformer Core
• Types of Construction
• Transformer Types
• Permeability and Magnetizing Characteristics
• Hysteresis Loop
• Phasor Diagram of Transformer
• Three Phrase Vector
• Transformer Rating
• Transformer Impedance
• Three Phrase Transformer

TRANSFORMERS CONNECTIONS AND MARKINGS

• Introduction to transformer connections and markings
• Winding Polarity
• Terminal Markings
• Relative Marking of Terminal
• Terminal Marking of tappings
• Winding Connections and Phasor
• Transformer Groups
• Delta Star Connections
• Delta Star and Star Delta Connection
• Star Connection
• Delta Delta Connections
• Zig Zag Connections
• Tertiary Windings
• Single phase load to Neutral
• Double Secondary Transformer
• Three Phase Connections
• Scott Connections
• Auto transformer
• Parallel Operation Transformer
• Power Station Auxiliary System
• Impedance of Parallel Connection
• Group I II III IV Connections
• Single Two Phase Connections

TRANSFORMER CORE

• Transformer Parts
• Transformer Parts Introduction
• Transformer Core
• Transformer Windings
• Transformer Short Circuit Currents
• Magnetic stray field and forces
• Short circuit effect radial collapse and types of stress
• Transformer Test Voltages
• Transformer Insulation
• Transformer Oil Requirements
• Oil molecules and properties
• Transformer Paper Insulation
• Transformer Paper Aging
• Cooling medium method and designation
• Transformer preservation bushings and tap changer
• Transformer Tests
• Transformer Service Conditions

POWER TRANSFORMERS AND SAFETY

• Introduction to transformer installation
• Electrical Schemes and Plant Layout
• Typical schemes in a plant
• Transformer Layout
• Typical Plant Layout
• Indoor Transformer
• Transformer Bushings
• Core and Coil Assembly
• Transformer Noise
• Transformer Noise Measurement and Minimizing
• Power Circuit Connections
• Changes in Operating Conditions
• Transformer at Higher Attitudes
• Installation and Pre-Commissioning Test at Site
• IR Test Arrangement
• Pre-Commissioning Checks
• Commissioning
• After and Permanently Energized
• Recommended Settings
• NZCEP35 Code of Practice
• Earthing System
• Touch Step Transferred Voltages
• Types and Requirement of Earth Electrodes
• Testing and Inspiration
• Shock Current
• Touch Voltage
• Step Voltage
• Transfer Potential
• Power System Neutral Earth
• Earthing System Design
• Transferred Earth Potential Rise
• Distribution System Earthing
• Neutral Connection to Earth
• Impedance of Earth Fault Current Path
• Earthing Connection and Earthing at Distribution Center
• Earthing or Fittings Other than at Distribution Center
• Fault Duration Earthing Conductors
• Earthing Connection
• Earthing Electrode Connections
• Recommended Earthing System

TRANSFORMER OPERATION AND MAINTENANCE

• Transformer operation and maintenance
• Transformers In Services
• Transformer Inspection
• Tap Changer Maintenance
• Moisture In Transformer
• Measurement of Moisture Content
• Removal of Moisture
• Oil Testing
• Duval Triangle Method
• Duval Triangle Plotting
• Ferro Resonance

TRANSFORMER PROTECTION

• Transformer Protection
• Need for earthing
• Consequences Solutions and benefits
• Earthing Methods
• Transformer Inrush currents
• Types of fault
• Relays for Protection
• Delta Star Transformer
• Spill Current
• Restricted Earth Fault
• Current Transformer Requirement