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 52883WA Advanced Diploma of Applied Electrical Engineering

How is this module assessed?

After completion of this assessment, you will be given a result of ‘Satisfactory’ or ‘Not Satisfactory’. The assessor will give you feedback via Moodle and you will have an opportunity to submit additional evidence if you have received a ‘Not Satisfactory’ result.

You will be allowed one (1) opportunity to resubmit the same assessment task if required.

For a ‘Satisfactory’ result in this assessment, all questions must be answered to a satisfactory standard and you must achieve an overall mark of 60% or above.

Once all assessment tasks for this module have been completed, you will be given a final module result of ‘Competent’ or ‘Not Yet Competent’. If you are deemed ‘Not Yet Competent’ in a module after all resubmission attempts, you will be required to re-sit the module.

 How is this assessment task assessed?

For a result of ‘Satisfactory’ in this assessment task, all module assessment criteria (as indicated on page 4) must be completed to a satisfactory standard.

Where a critical question is identified, you must receive a mark of 100% for these questions before a ‘satisfactory’ result can be awarded, regardless of the overall mark achieved.

At the Advanced Diploma level, a ‘satisfactory’ standard, as stipulated by the Australian Qualifications Framework, means that you will demonstrate the application of knowledge and skills:

  • with depth in areas of specialization, in contexts subject to change
  • with initiative and judgment in planning, design, technical or management functions with some direction
  • to adapt a range of fundamental principles and complex techniques to known and unknown situations
  • across a broad range of technical or management functions with accountability for personal outputs
  • personal and team outcomes within broad parameters

Assessors also make decisions based on the following considerations:

  • all parts of this assessment have been completed to a standard that satisfactorily meets the requirements set out in the assessment criteria (as per the module outline).
  • the assessment evidence provided is the student’s own work, except as appropriately acknowledged by the use of referencing.
  • the evidence is recent and the student’s knowledge is up-to-date

 Assessment Instructions:

  1. You must answer ALL questions.
  2. Please ensure you complete your answers in a blue font (not red or black).
  3. The best marks can be earned by giving concise, brief answers that address the questions.
  4. You must reference all content used from other sources including course materials, slides, diagrams, etc. Do not directly copy and paste from course materials or any other resources.
    Refer to the referencing section of the EIT eLibrary on Moodle for referencing guides.
  5. Use this document for completing your answers by typing the answers after each question without deleting the question. Make sure that you preserve the original question number format.
  6. Do not add extra pictures, etc. as annexures; instead, paste them directly into this answer sheet. Hand-drawn sketches can be inserted after scanning but please ensure that the file size does not become big (more than 10 MB). You must refer to all diagrams and pictures, etc. that you have drawn or pasted in.
  7. When saving your document (must be Word format), ensure you include your name in the title: COURSECODE_MODULE#_ASSESSMENTTYPE_VERSION#_YOURNAME

E.g. DEE_DEEEPD606_WrittenAssessment_v1_JohnSmith

Module no. and name: DEEEPD606: Electrical Power Distribution
Assessment type: Written
Total marks: 80 marks

Learning outcomes covered in this assessment:

LO1: Compare and contrast common power distribution systems

LO2: Evaluate a basic power distribution system

LO3: Define fault level in electrical systems and demonstrate its role in the choice of equipment

LO4: Explain in-plant generation

LO5: Outline maintenance and asset management in distribution systems

Important notes:

  1. Please answer in blue font and not in red or any other color.
  2. Please answer all the questions in Part 1 and Part 2 as it is MANDATORY to do so.

Part 1:        Short-answer Questions                                            (60 marks)

Q1 Name the four guiding principles for designing an electrical power distribution network. (2 marks)
A1 Student answer:

The guiding principle for designing an electrical power distribution network are:

1. Functions of the structure of the power distribution for the future and present time.

2. There will be the proper determination of the location of service of the entrance of the power supply.

3. There is the determination of the source of the power that will include normal mode, standby mode and also emergency mode.

4. There will be proper management of the efficiency of the energy and also the management of the resources (Kirschen & Strbac 2018)

F1 Assessor feedback: (marks awarded)
Q2 What are the two basic responsibilities of power consumers? (2 marks)
A2 Student answer:

The responsibilities of the power consumers are

1. there will be the proper mechanism of the energy efficiency of the power with the proper management of the resources.

2. The consumer has the right to inform all the characteristics and the policies regarding power consumption with the safety policies (Kirschen & Strbac 2018).

F2 Assessor feedback: (marks awarded)
Q3 Please select the voltage classification for the following systems as LV, MV or HV as per IEEE 141.

a)      415 V ac

b)      1100 V ac

c)      22000 V ac

d)      132000 V ac

(2 marks)
A3 Student answer:

a)         415 V ac- Medium Voltage (MV)

b)         1100 V ac- High Voltage (HV)

c)         22000 V ac- High Voltage (HV)

d)         132000 V ac- Extra High Voltage (EHV)

F3 Assessor feedback: (marks awarded)
Q4 Provide answers for the following:

a)      Expand:

i.            SAIFI, and

ii.             SAIDI.

b)      What are these values used for?

(2 marks)
A4 Student answer:

I.            SAIFI: The System Average Interruption Frequency Index

This is the average number of interruption that is faced by the customers in the connected feeders.

SAIFI= (Total no. of customers interrupted)/ (Total no. of Customers Served)

II.            SAIDI: System Average Interruption Duration Index

This is the average duration of the power interruption that is faced by the customers in a year (Kornatka 2017)

b) these values are used for the measurement of the index of the power interruption that is faced by the customers in the power supply.

F4 Assessor feedback: (marks awarded)
Q5 State the term used:

a)      Ratio of maximum demand to connected load is ______.

b)      Ratio of average load to peak demand is _______.

(2 marks)
A5 Student answer:

a) Ratio of maximum demand to connected load is Demand Factor.

b) Ratio of average load to peak demand is the Load Factor.

F5 Assessor feedback: (marks awarded)
Q6 List any two benefits of choosing the correct rating and location of power transformers in an electrical network. (2 marks)
A6 Student answer:

The two benefits of choosing the correct rating and location of power transformers in an electrical network are

1. The correct rating of the power transformer helps in better regulation of voltage in a home with proper efficiency and accuracy (Kornatka 2017).

2. The location of the power transformer helps in making the wires and connection in smaller length and also there is lowering the cost of the electricity.

F6 Assessor feedback: (marks awarded)
Q7 What is meant by the total cost of ownership with specific reference to power distribution? (2 marks)
A7 Student answer:

The total cost of the ownership is the cost of the total assets made by the owner in purchasing the electrical equipment like for the connection. This is at the individual or at the level of the business or any firm, the cost of total wiring, and other electrical items that are needed for the connection of the power and also the cost of the transformers that is needed for the power.

F7 Assessor feedback: (marks awarded)
Q8 Name at least four important ratings of an 11 kV CB. (2 marks)
A8 Student answer:

The four important ratings of the 11kV circuit breaker

1. Rated Short circuit breaking current

2. Rated short circuit making current

3. Rated short time current

4. Rated operating sequence of the circuit breaker (Chen et al.,2017).

F8 Assessor feedback: (marks awarded)
Q9 Provide answers for the following:

a)      For an insulator string which of these values will be higher: Creepage or clearance?

b)      What type of failures does creepage protect against?

(2 marks)
A9 Student answer:

a) The value of the creepage of the insulator string must be high so that there is more insulation in the string.

b) The creepage protects the person or power system from the electrical operating voltage in case of any malfunction of any electrical equipment.

F9 Assessor feedback: (marks awarded)
Q10 Why is a temperature limit important?

a)      For cables

b)      For overhead line conductors

(2 marks)
A10 Student answer:

a) the PVC cables of the electrical cables it is important to withstand the high temperature in case of a short circuit and this feature of long-lasting in the temperature there is less of the electrical hazards the temperature should be 250 ° C.

b) For the overhead line conductor temperature is more important because they are exposed to the environment and heat and this high wearing capacity of temperature helps in the long-lasting the conductors (Chen et al.,2017).

F10 Assessor feedback: (marks awarded)
Q11 List any two reasons why sufficient clearance should be maintained around HV switchgear panels. (2 marks)
A11 Student answer:

1. HV switchgear has high voltage which can burn any substance which is around the switchgear and this cause the fire risk of the transformer and leads to power failures in the electricity.

2. Clearance around the Switchgear should be cleaned at a regular period so that any hazard can be prevented (Renforth et al., 2018).

F11 Assessor feedback: (marks awarded)
Q12 List any two aspects of why is short circuit study important in the design of cables/bus bars. (2 marks)
A12 Student answer:

1. Shor circuit study was used to determine the fault in the current at each point of the system and this will help engineers in the required interrupting capacity.

2. this also helps in identifying the correct ways to solve the problem of the short circuit in the design of cables and this helps in making proper stress of the insulators and use of the insulating material for the cables and bus bars (Renforth et al., 2018)

F12 Assessor feedback: (marks awarded)
Q13 Pulling out of induction motors on voltage sags can be studied using ______. (Choose one).

a)      Stability study

b)      Voltage profile study

(2 marks)
A13 Student answer:

b)  Pulling out of induction motors on voltage sags can be studied using Voltage Profile Study.

F13 Assessor feedback: (marks awarded)
Q14 List any four causes of insulation failure in solid insulation. (2 marks)
A14 Student answer:

The four causes of insulation failure in solid insulation are:

1. harmonic distortion in solid insulators

2. Excessive current draw in the solid insulator

3. overheating of the solid insulator

4. Winding Contamination of the insulators

F14 Assessor feedback: (marks awarded)
Q15 List any four problems of high impedance arc faults. (2 marks)
A15 Student answer:

The problems of high impedance arc faults

1. Conductors are found broken and also touch the ground

2. there is a chance of the fire risk (Telford et al., 2016)

3. chances of the electric shock that can be a danger

4. may lead to the Three-phase ground fault (LLLGF)

F15 Assessor feedback: (marks awarded)
Q16 Choose faults where auto-reclosing of an overhead line is likely to be successful. (Choose one).

a)      Lightning flash

b)      Insulator failure

c)      Transformer winding insulation failure

d)      Underground cable fault

(2 marks)
A16 Student answer:

d) underground cable fault is most successful for choosing the auto-reclosing of an overhead line because this will avoid the unwanted digging of the underground cable and take them out for the repairing work.

F16 Assessor feedback: (marks awarded)
Q17 Which one of these two systems has a short circuit current with a high DC offset?

a)      System with high resistance and low reactance

b)      System with low resistance and high reactance

(2 marks)
A17 Student answer:

a) System with high resistance and low reactance has a short circuit with a high DC offset.

F17 Assessor feedback: (marks awarded)
Q18 List two examples of unbalanced faults. (2 marks)
A18 Student answer:

The two examples of unbalance faults are:

1. Single line-to-ground fault (SLG)

2. Line-to-line fault (L-L)

F18 Assessor feedback: (marks awarded)
Q19 How can the current be limited in the case of the following type of faults?

a)      Phase to earth (star connected system)

b)      3-phases faults

(2 marks)
A19 Student answer:

a) the wires of the electrical equipment that can be short-circuited with the done with the high flow of the electricity then there is a chance of the short circuit but extra current flows through the wire and earth absorb the current in this way current can be limited (Telford et al., 2016).

b) this will be limited by the impedance of the generator and the impedance of the line at the generation that can be managed through the symmetrical faults.

F19 Assessor feedback: (marks awarded)
Q20 List one example each for the study used for networks for making the system safe against:

a)      Electric shock

b)      Arc hazard

(2 marks)
A20 Student answer:

a) For the safety against the electric shock of the networks there is the use of the protective shield and also there is the use of the insulating material for the wires and system so that there will be no chance of getting electric shocks.

b) there will be proper distance and minimum recommended distance among the energised conductors so that there is less of arc flash in the circuit.

F20 Assessor feedback: (marks awarded)
Q21 Calculate the short circuit that a cable can withstand for 0.5 seconds if it can withstand 25 kA for 1 second. (2 marks)
A21 Student answer:

The short circuit will 12.5 kA

F21 Assessor feedback: (marks awarded)
Q22 Provide answers for the following:

a)      What will be the fault kVA for a 3-phase 1500 kVA transformer with 0.06 pu impedance?

b)      What is the secondary short circuit (line) current if the secondary line voltage is 440V?

(2 marks)
A22 Student answer:

a) I(fault) = S(kVA) x 100 / (1.732 x V(V) x %Z)

I(fault) = 1500 x 100 / (1.732 x 440 x 6)

= 32.80 kA

b) 32.78 kA

F22 Assessor feedback: (marks awarded)
Q23 A 3-phase 5 MVA transformer has a p.u impedance of 0.06. What is the p.u impedance when referred to a base of 55MVA? (2 marks)
A23 Student answer:

Impedance= 0.66

F23 Assessor feedback: (marks awarded)
Q24 List any two causes of failures in electrical distribution systems. (2 marks)
A24 Student answer:

The two causes of failures in electrical distribution systems are:

1. There may be chances of the poor design of electrical distribution systems which may result in failures.

2. There may be chances of the failure of the transformers which leads to the failure of the electrical distribution system (Sallam & Malik 2018).

F24 Assessor feedback: (marks awarded)
Q25 List any two effects of power interruptions. (2 marks)
A25 Student answer:

The two effects of power interruptions are:

1. The power failures lead to the data loss of productivity which results in a huge impact on the individual or any organisation.

2. The power interruption leads to the disruption of communications which has a great impact on the community (Sallam & Malik 2018).

F25 Assessor feedback: (marks awarded)
Q26 Give one example each for:

a)      Direct, and

b)      Indirect losses due to power outage.

(2 marks)
A26 Student answer:

a) If there is a cyclone that strikes the town and the transformer of the building is blown away in this case there is a direct power outage.

b) If there is power loss in a particular room of the building or any particular floor of the building due to a short circuit then this is an example of an indirect power outage.

F26 Assessor feedback: (marks awarded)
Q27 Which of the generating systems below can be used as black start sources?

a)      Gas turbine

b)      Steam turbine

c)      Diesel Engine

(2 marks)
A27 Student answer:

c) For the generating system diesel Engine can be used as the black start source this can be used as the power supply for the big generator that can help for the start of the big generator (Oruc & Dincer 2021).

F27 Assessor feedback: (marks awarded)
Q28 Expand the following abbreviations:

a)      RTU

b)      IED

(2 marks)
A28 Student answer:

a) RTU: Remote Terminal Unit

This is used to connect different hardware for the distribution of the power supply

b) IED: Intelligent Electric Device

this is used as an added device to the industrial Control system to make advanced power automation (Oruc & Dincer 2021).

F28 Assessor feedback: (marks awarded)
Q29 List any two systems’ fault/disturbance recordings measured by a SCADA system. (2 marks)
A29 Student answer:

1. the recording that is related to the incident can be recorded at the end of the circuit of the electrical power with the involved circuit (Kermani et al., 2021).

2. indirectly related to the incident that occurs during sustaining the circuit reading with the proper recording of the circuit that is not directly involved in a specific incident.

F29 Assessor feedback: (marks awarded)
Q30 List the four types of maintenance approaches normally practised. (2 marks)
A30 Student answer:

The four types of maintenance approaches normally practised are:

1. Corrective maintenance

2. Preventive Maintenance

3. Risk-based Maintenance

4. Condition-based maintenance

F30 Assessor feedback: (marks awarded)

Part 2:        Descriptive Questions                                                (20 marks)

Q31 Provide answers for the following:

a)      What is meant by embedded generation? (1 mark)

b)      List any two sources used for such generation. (1 mark)

c)      List any three major advantages of embedded generation compared to centralized power plants. (3 marks)

(5 marks)
A31 Student answer:

a) This is the process of the generation of electricity at a particular location and then providing the electricity to the main supply for the distribution of the electricity network.

b). The two sources of the embedded generation are:

i. Hydroelectric power plant

ii. Nuclear Power plan (Ohijeagbon & Ajayi 2015)

c) The three major advantages of embedded generation compared to centralized power plants are:

i. There is a reduction in the loss of the transmission of the electricity to the electric systems of the power supply.

ii. The embedded generation leads to generating clean and green energy which reduces the environmental concern for the generation of electricity and supply of the electricity.

iii. The embedded generation of the electricity will help in avoiding the electric hazard with the continuous monitoring of the power supply to the electric grid this will help in reducing the load on the cables of the electric and also reduce the electric hazards due to the overload of the electricity (Kennedy & Agalgaonkar 2016).

F31 Assessor feedback: (marks awarded)
Q32 Briefly explain the different types of power distribution approaches adopted by utilities and industries. (5 marks)
A32 Student answer:

The different types of power distribution approaches that are adopted by the utilities and industries are:

1. AC distribution System:

In this system, the consumption of power is in the form of AC. The electricity that is needed and transmitted in the form of the AC Power and this current can be easily stepped up and stepped down by the transformers. According to the voltage level of the AC Power, there are also two types of system (Jenkins & Pérez-Arriaga 2017)


i. Primary distribution system: In this system, the use of the voltage level is slightly higher than the utilization voltage. In this case, there is a 3-phase system and the range of the voltage is 3.3kV, 6.6kV & 11kV

ii. Secondary Distribution System: In this system, the power supply of the voltage is low 11kV to 415V and this is used for small consumers like household workers.

2. Radial System: this system has a separate feeder for the power in each area and the direction of the power in only one direction only and there is less cost and their low reliability of this system.

3. Ring main System: this system has its name with the connection in the loop with the single transformer supply to all the distributors and this is connected with the substation of the electrical power plant (Jenkins & Pérez-Arriaga 2017).

F32 Assessor feedback: (marks awarded)
Q33 Two transformers are connected in parallel for stepping down the voltage from 66 kV to 22 kV. Their ratings are 15 MVA and 30MVA with impedance values of 0.08 pu and 0.16 pu.

What will be the fault of MVA if there is a short circuit on the 22 kV bus?

All other impedances in the system can be neglected. Perform the calculation using a base MVA of 200MVA.

Show that the fault level of the parallel combination obtained in this method is the same as the sum of the fault MVA of the two transformers when operating alone.

(5 marks)
A33 Student answer:

for the transformer1 the fault will be

I(fault) = S(kVA) x 100 / (1.732 x V(V) x %Z)

I(fault) = 15 x 100 / (1.732 x 440 x8)

= 0.246kA

For transformer 2 the fault will be

I(fault) = S(kVA) x 100 / (1.732 x V(V) x %Z)

I(fault) = 30 x 100 / (1.732 x 440 x 16)

= 0.246 kA

In the parallel combination of the transformer fault

T1+T2= 0.246+0.246

= 0.492kA

When impendence = 0

MVA rating = 200MVA

Then the fault will be = S(kVA) x 100 / (1.732 x V(V) x %Z)

And when neglected the impedance hence the impedance will be 0 then there Is an infinite fault in the system.

Hence from the above calculation of the combination of the transformers in the parallel circuits and the sum of the faults MVA is equal when they are operating alone with the transformer1 and transformer2.

F33 Assessor feedback: (marks awarded)
Q34 Provide answers for the following:

a)      Differentiate between Planned preventive maintenance and condition-based maintenance.

b)      List the condition monitoring tests used for:

i.            Circuit breakers

ii.             Transformers

iii.            Cables, and

iv.            Busbars

(need two examples for each category).

(5 marks)
A34 Student answer:


Preventive maintenance Condition-based maintenance
1. This is done on the fixed schedule of the maintenance and this allows all the predict the well aligned with the maintenance This maintenance has the sensors and data that are already present in the system and they indicate the condition of the system.
2. the data that is needed for this maintenance is determined by the time and information on the schedule This maintenance requires single metrics that have pre-set thresholds of the system.
3. this maintenance is also known as routine maintenance. This is also is as the condition-based monitoring
4. there is advanced maintenance of the equipment that helps in making more accurate and effective the condition of the equipment (de Jonge et al., 2017). There is no possibility of the advance maintenance of the equipment this only can maintain once the condition changed.


I.            Circuit Breaker:  The condition monitoring test that is used is

1.      Off-line Monitoring

2.      Continuous Monitoring

3.      Real-time Monitoring

II.            Transformers: the condition monitoring test that is used are:

1.      Tan delta on winding monitoring test

2.      Monitoring test for the test of the Polarization

3.      Monitoring test of the Furan Analysis of the transformers

III.            Cables:  the condition monitoring test that is used are

1.      The test of the withstand testing of cable

2.      There is also a testing of the partial discharge of cable current

3.      There is the testing of the tan delta of the cable

IV.            Busbars: the condition monitoring test that is used are

1.      Use of the Yokogawa DTSX innovative temperature for the overheating sensors of the temperatures

2.      The maintenance can be done in the condition of the blackout

3.      There is always the maintenance of the switchboards and also emergency generators for keeping better solutions of the monitoring.

F34 Assessor feedback: (marks awarded)


Kirschen, D. S., & Strbac, G. (2018). Fundamentals of power system economics. John Wiley & Sons.

Chen, Z., Yu, Z., Zhang, X., Wei, T., Lyu, G., Qu, L., … & Zeng, R. (2017). Analysis and experiments for IGBT, IEGT, and IGCT in hybrid DC circuit breaker. IEEE Transactions on Industrial Electronics65(4), 2883-2892.

Renforth, L. A., Giussani, R., Mendiola, M. T., & Dodd, L. (2018). Online partial discharge insulation condition monitoring of complete high-voltage networks. IEEE Transactions on Industry Applications55(1), 1021-1029.

Telford, R. D., Galloway, S., Stephen, B., & Elders, I. (2016). Diagnosis of series DC arc faults—A machine learning approach. IEEE Transactions on Industrial Informatics13(4), 1598-1609.

Sallam, A. A., & Malik, O. P. (2018). Electric distribution systems.

Oruc, O., & Dincer, I. (2021). Development and performance assessment power generating systems using clean hydrogen. Energy215, 119100.

Kermani, M., Adelmanesh, B., Shirdare, E., Sima, C. A., Carnì, D. L., & Martirano, L. (2021). Intelligent energy management based on SCADA system in a real Microgrid for smart building applications. Renewable Energy171, 1115-1127.

Ohijeagbon, O. D., & Ajayi, O. O. (2015). Solar regime and LVOE of PV embedded generation systems in Nigeria. Renewable Energy78, 226-235.

Kennedy, J., Ciufo, P., & Agalgaonkar, A. (2016). A review of protection systems for distribution networks embedded with renewable generation. Renewable and Sustainable Energy Reviews58, 1308-1317.

Jenkins, J. D., & Pérez-Arriaga, I. J. (2017). Improved regulatory approaches for the remuneration of electricity distribution utilities with high penetrations of distributed energy resources. The Energy Journal38(3).

de Jonge, B., Teunter, R., & Tinga, T. (2017). The influence of practical factors on the benefits of condition-based maintenance over time-based maintenance. Reliability engineering & system safety158, 21-30.

Kornatka, M. (2017, May). Distribution of SAIDI and SAIFI indices and the saturation of the MV network with remotely controlled switches. In 2017 18th International Scientific Conference on Electric Power Engineering (EPE) (pp. 1-4). IEEE.

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