BEE206S

Unit Description and General Aims

The objective of this unit is to provide students with a fundamental knowledge of earthing, lightning/surge protection, and their relevance to electrical safety. Information covered in this unit will include: the earthing of power supply systems; protective earthing; hazards posed by lightning to personnel and equipment; methods of providing lightning protection to structures and surge protection to electrical circuits; safety requirements for electrical workers; and, legislative provisions to be fulfilled in regard to earthing and lightning/surge protection. Students will also undertake case studies of industrial projects and operations in the context to their country.

Learning Outcomes

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

1. Explain electrical system earthing and protective earthing.
   Bloom’s Level 2
2. Research and explain the procedure for designing an appropriate earthing system for electrical substations and measurement of earth resistance and earth fault loop resistance.
   Bloom’s Level 4
3. Explain the need for lightning protection of buildings and electrical facilities and the basic approach for evaluating protection effectiveness.
   Bloom’s Level 2
4. Describe how to design a comprehensive lightning and surge protection system for a building and evaluate its effectiveness.
   Bloom’s Level 4
5. Identify the electrical safety hazards present in a given environment and plan appropriate risk prevention and control measures.
   Bloom’s Level 3
6. Discuss electrical safety legislation applicable in Australia and its impact on the design/operation of electrical systems.
   Bloom’s Level 4

Student assessment

Prescribed and Recommended Readings

Required textbook(s)

Practical Grounding of Utility and Industrial Distribution Systems (US), Revision 2.1, IDC Technologies

Practical Electrical Safety Techniques for Industry (EF), Revision 4, IDC Technologies

Practical Earthing, Bonding, Lightning & Surge Protection (ER), Revision 8, IDC Technologies

Lightning, Surge Protection and Earthing of Electrical & Electronic Systems in Industrial Networks (LZ), Revision 8.1, IDC Technologies

Reference Materials

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

For example:

http://www2.schneider-electric.com/documents/support/white-papers/electric-utilities/arc-flash-mitigation-r0-db.pdf :

Arc Flash Mitigation by Antony Parsons, Ph.D., P.E., a white paper from Schneider Electric Company.

S. Alyami, "Grid Grounding Calculations for a 132-KV Substation Using Soil Backfilling," in IEEE Access, vol. 7, pp. 104933-104940, 2019, doi: 10.1109/ACCESS.2019.2932447.

M. Nassereddine and A. Hellany, "Designing a Lightning Protection System Using the Rolling Sphere Method," 2009 Second International Conference on Computer and Electrical Engineering, Dubai, 2009, pp. 502-506, doi: 10.1109/ICCEE.2009.140.

M. A. Salam, Q. M. Rahman, S. P. Ang and F. Wen, "Soil resistivity and ground resistance for dry and wet soil," in Journal of Modern Power Systems and Clean Energy, vol. 5, no. 2, pp. 290-297, March 2017, doi: 10.1007/s40565-015-0153-8.

Unit Content

Topics 1 and 2

Electrical system and protective earthing

1. Electrical system earthing – objectives
2. Types of system earthing and choosing an appropriate system for different applications
3. Earthing transformer for 3-wire supply
4. Protective earthing
5. Equipotential bonding
6. Extending system earthing to protective conductors and system types (TN, TT and IT)
7. Use of MEN systems by utilities and the benefits
8. Earth fault loop impedance and its measurement; relevance to earth fault protection

Topics 3 and 4

Earth electrode and substation earthing design

1. Soil resistivity and factors that influence resistivity
2. Measurement of soil resistivity
3. Earth electrodes and common types of electrodes
4. Applicable codes on earthing
5. Measurement of earth electrode resistance and earth grid resistance
6. Electric shock and tolerance to current
7. Touch, step, and transferred voltage
8. Earth grid design, earth potential rise, and computation of touch and step voltage

Topics 5 and 6

Lightning protection, surge protection and EMI control, and the role of earthing

1. Lightning physics and statistical distribution of lightning parameters
2. Direct and indirect effects of the lightning strike on objects
3. Side flash and methods of avoidance
4. Lightning protection of buildings-approach
5. Evaluation of protection effectiveness
6. Lightning surges and methods of surge coupling
7. Surge protection of electrical circuits and energy grading of protection
8. Design of comprehensive lightning of a facility
9. Electromagnetic interference, propagation and control
10. Role of earthing in control of EMI

Topics 7 and 8

Electrical safety hazards including electric shock and arc flash

1. Hazards in electrical work
2. Shock hazard and control measures
3. Direct and indirect contact
4. Relevance of earthing in mitigation of indirect contact
5. Equipment of class 1, 2 and 3
6. Safe clearances and its relevance in outdoor switchyards
7. Arc flash hazard
8. Arc flash hazard assessment procedure
9. Calculation of arc energy and flash protection boundary
10. Hazard control measures
11. Hazardous area classifications
12. Safety in hazardous locations

Topic 9

Static electricity and hazard control

1. Basic principles of static charge formation
2. Problems caused by static electricity
3. Explosion hazard of static electricity
4. Calculation of spark energy
5. Mitigation of static-related problems in equipment
6. Bonding and its role in mitigation
7. ESD and basics of protection against damage to sensitive components

Topics 10 and 11

Electrical safety legislation and its impact on the design and operation of electrical systems

1. A brief history of safety (WHSD) legislation
2. Electrical safety-related legislation
3. The 3-tiers of legislation
4. Typical legislation and its objectives
5. Australian wiring rules-an overview
6. Safety measures (technical, procedures, organisational)
7. Hazard control triangle
8. Design of electrical equipment to ensure safety
9. Electrical substation safety including hazards in battery installations
10. WHS procedures for safe electrical work

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

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• Additional resources or files: N/A

Hardware

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