DAY ONE
Part 1. Transformer Design and Construction
Students will be introduced to the different types of single- and three-phase transformers 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 Core
- Transformer Core
- Core Form and Shell Form
- Core Loss
- Exciting Current
- Noise level
- Structure
Transformer Windings
- Winding Conductors - ASTA
- Load Loss
- Impedance and voltage drop
- Winding Insulation
- Cooling Structure
- Short Circuit Withstand Capability
- Core and Coil Assembly
Transformer Insulation
- 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
Transformer Tank
- Main Tank
- Main Tank Components
- Seals, Gaskets and Valves, Bushings
Oil Preservation Systems
- Air Cell Systems
- Breathing Systems
- Auto-Recharging Dehydrating Breather
- Oil Cooling Systems
Transformer Bushings
- 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
Tap Changers
- LTC
- DETC (OCTC)
- ULTC
- Headboard Links
Components and Accessories
- Top Oil Temperature Monitoring
- Devices/Indicators
- Winding Temperature Monitoring
- Devices/Indicators
- Liquid Level Gauges/Indicators
- Pressure and Vacuum Gauges/Indicators
- Pressure Relief Device
- Gas Detection Relays
- Alarm and trip functions are equipped and preset
Part 2. Transformer Operation and Appplication
Transformer Applications and Types
- Dry Type
- Liquid Filled
- Industrial vs Public Distribution
- Potential Transformers (PTs)
- Current Transformers (CTs)
- Control and Power Supply Transformers
- Auto Transformers
Transformer Operation and Theory
- 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
Transformer Cooling
- Transformer Cooling Techniques and Devices
Three-Phase Theory/Transformer Types
- Transformer Configuration
- Three Phase Transformer Connections
- Delta Connection
- Wye 'Star' (Y) connection
- Voltage and Current in Various Combinations
- Transformer Terminal Markings and Identifications
Resistive Loads
- Inductive Loads
- Capacitive Loads
Three-Phase Ratio's
- Parallel Operation of 3 Phase Transformers
- Phase Angle Shift
- Phase Rotation
- Grounding Transformers
- Auto Transformers
- Regulators
- Phase Shifters
- Three-Phase Ratios
Transformer De-Rating
Transformer Failures
- 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
DAY TWO
Transformer Field Diagnostics Tests and Techniques
Part 3. Transformer Field Diagnostic Testing and Maintenance Techniques
WINDING RESISTANCE
- Testing Techniques
- Voltmeter – Ammeter Method
- Bridge Technique
- Micro Ohmmeter
TRANSFORMER RATIO/POLARITY
- Testing Techniques
- Inductive Kick (DC Method) Polarity
- Alternative Voltage (AC Method) Polarity
- Turn Ratio Test Set
- Double Voltage Meters
EXCITATION CURRENT MEASUREMENT
- Hysteresis
- Eddy currents
- Copper losses
SHORT CIRCUIT IMPEDANCE MEASUREMENT
- Testing Techniques
- Voltmeter – Ammeter Method
SWEEP FREQUENCY RESPONSE ANALYSIS
- Testing Techniques
- Problems Detected
- Shifted Winding/Core
- Deformed Windings
- Loose Windings
INSULATION RESISTANCE
- Testing Techniques
- Megger
- Polarization Index Test (PI)
- Can Detect the Following Problems
- Insulation Dryness
- Insulation Contamination
- Sensitive to Temperature
INSULATION CAPACITANCE AND POWER FACTOR
- Testing Techniques
- Capacitance Bridge Method – DF
- AC Dielectric Loss Method - PF
PARTIAL DISCHARGE MEASUREMENT
- Can Detect the Following Problems
- Insulation Defects
- Insulation Contamination
- Air bubbles trapped in Insulation
- Localized High Electrical Stress
- PD is the "Cancer" of Insulation System
- PD Detector
- RIV
TRANSFORMER CORE TESTING
- Problems
- Insulation Resistance
- More Grounding Points
- Megger
- Separate external core ground lead from 250
resistor
- Measure core
Brian Sparling, GE Energy
Claude Beauchemin, GE Energy
INSULATING OIL
BUSHING VISUAL CHECK
- Oil Level
- Leaking
- Chipped Porcelain
- Fractured Flange
- Poor Gaskets
- Peeled Painting
- Terminal Connection
- Corrosion
TAP CHANGERS
- DETC
- Contact Resistance Increase
- Loose Contact Pressure
- Misalignment
- Electrical and mechanical centers
- LTC
- Contact Continuity
- Arcing Switch and Tap Selector
- Drive Mechanism Operation
- Motor
- Timing
- Oil Compartment
- Protection and Control
TRANSFORMER TANK
- Visual Check
- Oil Leaking
- Poor Gaskets
- Peeled Painting
- Rust/Corrosion
- Temperature Hot Spot
COMPONENTS AND ACCESSORIES
- Visual Check and Function Test
- Cooling System – Radiators, Fans or Pumps
- Gauges and Indicators – Oil Level, Pressure and Temperature
- Pressure Relief Device
- Gas Relay
- Air Breather
- Inert Air System
- Oil Filters
INFRARED TEMPERATURE MEASUREMENT
Course Timetable for Both Days:
- START: 8:00AM
- COFFEE BREAK: 10:00AM
- LUNCH: 12:00PM
- REFRESHMENT BREAK: 2:30PM
- FINISH: 4:30PM