Last Updated S012019


Unit Name Transformers and Switchgears
Unit Code BEE205S
Unit Duration 1 Semester

Bachelor of Science (Engineering)

Duration 3 years    

Year Level Two
Unit Creator / Reviewer N/A
Core/Sub-discipline: Sub-discipline
Pre/Co-requisites BSC102C
Credit Points


Total Course Credit Points 81 (27 x 3)

Mode of Delivery Online or on-campus. 
Unit Workload (Total student workload including “contact hours” = 10 hours per week; 5 hours per week for 24 week delivery)
Pre-recordings / Lecture – 1.5 hours
Tutorial – 1.5 hours
Guided labs / Group work / Assessments – 2 hours
Personal Study recommended – 5 hours

Unit Description and General Aims

The objective of this unit is to provide students with a detailed knowledge of the building blocks of a power system in terms of transformers and switchgear. Information covered in this unit will include: the theory of transformers and switchgear; their design and construction features; and, their operation, maintenance, and testing. On completion of this unit, students will be able to: specify the appropriate equipment to use for a given application; plan an installation; explain the commissioning and maintenance requirements of the equipment; and, troubleshoot any problems that may occur. Students will also undertake a project involving transformers and switchgear specification, selection, and operation, contextualised to their country/state.

Learning Outcomes

On successful completion of this Unit, students are expected to be able to:

  1. Explain the basic principles of transformers including the phasor diagram and equivalent circuit.
    Bloom’s Level 2
  2. Identify the most appropriate type of transformer for a given application and determine its ratings and design features.
    Bloom’s Level 5
  3. Create a plan for scheduled inspection and predictive tests required for the trouble-free operation of a power transformer of a network substation, whilst keeping the environment and sustainability aspects in mind.
    Bloom’s Level 6
  4. Describe the principle of current interruption by a circuit breaker.
    Bloom’s Level 2
  5. Select the appropriate type of switchgear for an industrial power facility and determine the specifications for the selected switchgear.
    Bloom’s Level 6
  6. Plan the facilities required for a substation installation (including one or more transformers and MV switchgear), whilst keeping environment and sustainability aspects in mind.
    Bloom’s Level 6

Student assessment

Assessment Type When assessed Weighting (% of total unit marks) Learning Outcomes Assessed

Assessment 1

Type: Multi-choice test / Group work / Short answer questions / Practical / Remote Lab / Simulation

Example Topic: Transformers.

Students will complete a quiz with MCQ type answers to 30 questions to demonstrate a detailed knowledge of transformer theory and construction.

Due after Topic 5 15% 1, 2, 3

Assessment 2 

Type: Multi-choice test / Group work / Short answer questions / Practical / Remote Lab / Simulation

Example Topic: Transformers and circuit breakers.

Students will complete a test with about 20 questions each to be answered in less than 100 words and explanatory diagrams to demonstrate a detailed knowledge of transformer O&M and applications and Circuit breaker theory.

Due after Topic 9 20% 4, 5

Assessment 3

Type: Multi-choice test / Group work / Short answer questions / Practical / Remote Lab / Simulation / Project / Report

Example Topic: Practical work covering the application/planning aspects of transformers and switchgear for a specified substation using software such as EasyPower to simulate the results.

Due after Topic 11 20% 5, 6

Assessment 4

Type: Exam

Example Topic: Transformers, circuit breakers, and switchgear.

An examination with a mix of detailed essay type questions and numerical problems to be completed within 2 hours.

Final Week 40% 1 to 6

Attendance / Tutorial Participation

Example: Presentation, discussion, group work, exercises, self-assessment/reflection, case study analysis, application.

Continuous 5% 1 to 6


Prescribed and Recommended Readings

Required textbook(s)

EIT reference books on Transformers, Circuit breakers (Course code TF and CB)

Reference Materials

Number of peer-reviewed journals and websites (advised during lectures)

For example: A Guide to Transformer Oil Analysis by I.A.R. GRAY Transformer Chemistry Services.

Unit Content


Topics 1 and 2

Transformer basic theory and ratings

1. Electromagnetic induction
2. Basic transformer theory using a single phase transformer example
3. Transformer equations
4. Equivalent circuit of a transformer
5. Phasor diagram
6. Transformer regulation and efficiency

Topics 3 and 4

Three phase transformers, types, and construction

1. Three phase transformer: core and shell type
2. Power and distribution transformers
3. Construction of transformers – basic components
4. Insulation and cooling
5. Mounted accessories, tap changers (off-load and on-load)
6. Special types: Furnace Transformer, Rectifier Transformer/K-Rating, Dry Type Transformers
7. Non-linearity in transformer magnetising characteristic on power quality

Topics 5 and 6

Transformer operation, maintenance, and testing

1. Installation requirements of transformers, fire prevention, and control
2. Parallel operation
3. Transformer inspection and maintenance
4. Testing of transformer oil, and drying of transformers
5. Transformer tests during commissioning and maintenance
6. Predictive testing (DGA, Frequency response, PD measurements, DP/Furan analysis etc.)

Topic 7

Basic principles of current interruption – disconnectors and circuit breakers

1. Offload, load break, and fault interrupting devices
2. Circuit interruption, basic principles of arc behaviour
3. Transient recovery voltage, current chopping/pre-strike in circuit breakers
4. General requirements of circuit breakers (Main and arcing contacts, arc quenching devices)
5. Switching transients due to inductor/capacitor switching and transformer switching and methods used (Resistor break, point-on-wave switching)
6. Circuit breaker ratings and applicable standards; special applications
7. Duty cycle and other test requirements

Topics 8 and 9

LV, MV and HV circuit breakers

1. LV circuit breakers types with air as quenching medium (ACB, MCCB, MCB, ELCB)
2. Historical background – bulk oil and minimum oil circuit breakers
3. Vacuum CB, SF6 CB and Auto-Reclosers for MV applications
4. Air-blast CB and SF6 CB for HV applications
5. Operating mechanism of LV/MV CB (direct actuation/mechanical stored energy type) and HV (pneumatic and hydraulic)
6. Control circuit of CB and interlocks

Topics 10 and 11

LV, MV and HV switchgear

1. Switchgear definition and types
2. LV and MV switchgear construction
3. Switchgear components and applications
4. LV and MV switchgear ratings and standards
5. HV outdoor switchyards and bus configurations
6. Gas-insulated switchgear

Topic 12

Unit Review

In the final week students will have an opportunity to review the contents covered so far. Opportunity will be provided for a review of student work and to clarify any outstanding issues. Instructors/facilitators may choose to cover a specialized topic if applicable to that cohort.

Software/Hardware Used


  • Software: EasyPower
  • Version: 9.6 or 9.7 
  • Instructions: Use remote Lab to access this software OR download demo version.
  • Additional resources or files: 
    Full Version: To access the software, log into our Remote Lab 10 (Lab 10) Remote Lab ProfiBus, or Remote Lab 12


  • Hardware : N/A