At the end of the course, participants should be able to:

• Explain the purpose and principles of high voltage electrical testing.
• Apply the relevant safety requirements when carrying out or supervising HV tests.
• Select suitable testing methods and equipment for different electrical systems.
• Carry out and interpret insulation resistance and related insulation tests.
• Explain and apply AC, DC and VLF testing procedures.
• Understand the principles of partial discharge testing and interpret typical test results.
• Use TDR principles to identify and locate cable faults.
• Carry out appropriate earth electrode and soil resistivity tests.
• Understand the main commissioning and maintenance tests applied to power transformers.
• Interpret transformer insulation, winding, ratio and vector group test results.
• Evaluate transformer oil-test results and identify indications of deterioration.
• Understand the operation and purpose of Buchholz, pressure relief and temperature protection devices.
• Assess test results and identify when further investigation or remedial work is required.
• Maintain appropriate testing and inspection records.

Day 1: Electrical Insulation and High Voltage Testing

1. Introduction to High Voltage Testing

• Purpose and objectives of electrical testing
• Types of electrical tests
• Commissioning, acceptance and periodic testing

2. Electrical Insulation

• Purpose and characteristics of electrical insulation
• Types of insulation used in high voltage equipment
• Insulation ageing and deterioration
• Common causes of insulation failure

3. Safety Requirements

• Hazards associated with high voltage testing
• Isolation and earthing
• Test area control and access restrictions
• Safety distances and warning arrangements
• Discharge and temporary earthing of test objects
• Applicable electricity regulations and standards

4. Insulation Resistance Testing

• Principles of insulation resistance measurement
• Test voltages and test procedures
• Polarization Index (PI)
• Dielectric Absorption Ratio (DAR)
• Factors affecting insulation resistance
• Temperature effects and correction
• Interpretation of test results

5. Flash Testing

• Purpose and application
• Test arrangements
• Flashover and insulation breakdown
• Safety precautions
• Evaluation of test results

6. AC and DC Pressure Testing

• Principles of AC withstand testing
• Principles of DC withstand testing
• Test equipment and connections
• Test voltage and duration
• Leakage current
• Test procedures and safety precautions
• Interpretation of test results

Day 2: VLF Testing, Partial Discharge and Cable Fault Location

1. VLF Testing

• Purpose and applications of VLF testing
• VLF test equipment
• Test connections and procedures
• Withstand and diagnostic testing
• Interpretation of VLF test results
• Safety requirements and discharge procedures

2. Partial Discharge Testing

• Principles of partial discharge
• Causes of partial discharge in insulation
• Internal, surface and corona discharge
• PD inception and extinction
• Partial discharge measurement
• Phase-resolved partial discharge patterns
• Testing of cables, joints and terminations
• Interpretation of typical PD results

3. Time Domain Reflectometry

• Principles of TDR
• Cable characteristics and signal reflections
• Open and short circuit indications
• Cable length measurement
• Fault location
• Interpretation of TDR traces

4. Practical Exercises and Tutorials

• Insulation resistance testing
• PI and DAR measurements
• HV pressure-testing procedures
• VLF testing exercise
• Interpretation of partial discharge results
• TDR cable fault-location exercise

Day 3: Earth Electrode Testing

1. Introduction to Earthing Systems

• Purpose of earthing
• HV earthing systems
• Earth electrodes and earth grids
• Earth resistance
• Soil resistivity
• Step and touch voltage
• Earth potential rise

2. Purpose of Earth Electrode Testing

• Initial and commissioning tests
• Periodic testing
• Testing following installation or modification
• Factors affecting earth resistance measurements

3. Testing Conditions and Safety

• Test site preparation
• Isolation requirements
• Auxiliary electrodes
• Test lead arrangements
• Effects of weather and soil conditions
• Electrical safety during earth testing

4. Earth Testing Equipment and Methods

• Earth resistance test instruments
• Three-point / fall-of-potential method
• Four-point soil resistivity testing
• Selective earth resistance testing
• Clamp-on earth resistance testing
• Selection of the appropriate test method

5. Practical Testing Procedures

• Test connections
• Measurement procedure
• Verification of readings
• Sources of measurement error
• Evaluation of test results

6. Applicable Standards and Regulations

• Applicable regulations and standards
• Acceptance requirements
• Assessment of unsatisfactory results
• Common causes of high earth resistance
• Remedial measures

Day 4: Transformer Design, Construction and Testing

1. Transformer Design and Construction

• Transformer operating principles
• Transformer ratings
• Core and winding construction
• Insulation system
• Cooling arrangements
• Bushings and tap changers
• Conservator and breather systems
• Transformer accessories

2. Transformer Safety

• Electrical and mechanical hazards
• Isolation and earthing
• Transformer oil hazards
• Fire protection

3. Periodic and Post-Installation Testing

• Factory and site testing
• Commissioning tests
• Routine tests
• Periodic condition assessment

4. Transformer Insulation Testing

• Insulation resistance
• Polarization Index
• Winding-to-earth testing
• Winding-to-winding testing
• Temperature effects

5. Open Circuit and Short Circuit Tests

• Purpose of the tests
• Test arrangements
• Core losses
• Magnetizing current
• Copper losses
• Transformer impedance
• Interpretation of test results

6. Vector Group Testing

• Transformer polarity
• Phase displacement
• Vector group identification
• Requirements for parallel operation

Day 5: Transformer Condition Assessment and Maintenance

1. Transformer Oil Testing

• Purpose and properties of transformer oil
• Oil sampling
• Dielectric breakdown voltage
• Moisture
• Acidity

2. Transformer Diagnostic Tests

• Insulation resistance
• Winding resistance
• Transformer turns ratio
• Excitation current
• Oil testing
• Temperature monitoring
• Introduction to Dissolved Gas Analysis (DGA)
• Introduction to Sweep Frequency Response Analysis (SFRA)

3. Transformer Protection and Monitoring Devices

• Buchholz Protection Unit
• Construction and operating principle
• Alarm and trip functions
• Causes of gas accumulation
• Investigation following Buchholz operation
• Pressure Relief Devices
• Operating principle
• Causes of excessive internal pressure
• Alarm and trip arrangements
• Inspection and testing
• Temperature Devices
• Oil temperature measurement
• Winding temperature measurement
• Alarm and trip settings
• Temperature monitoring

4. Transformer Routine Maintenance

• Visual inspection
• Bushings
• Oil system
• Conservator and breather
• Cooling fans and pumps
• Tap changer
• Connections and earthing
• Protection devices
• Oil leaks and abnormal conditions

• Electrical Engineers.
• HV Technicians.
• Commissioning Engineers.
• Maintenance Supervisors.
• Power System Professionals.