48583 Power Systems Operation and Protection

Warning: The information on this page is indicative. The subject outline for a particular semester, location and mode of offering is the authoritative source of all information about the subject for that offering. Required texts, recommended texts and references in particular are likely to change. Students will be provided with a subject outline once they enrol in the subject.

Subject level:

Undergraduate

Recommended studies: power circuit theory knowledge is essential for this subject; complex numbers and its application to the analysis of AC circuits; power circuit analysis and fault calculations; fundamentals of electrical machines; MATLAB programming to solve simple problems

Handbook description

The primary objective of this subject is the development of a working knowledge of power systems operation and protection. The subject aims to provide students with a knowledge and understanding of elements of the supply chain and how they function in the National Electricity Market; demand-side management options including smart meters; load forecasting and optimal load scheduling for secure energy supply and use; protection schemes for transmission and distribution networks; communications in power systems, including communication media, architectures, automation, standards, protocols and security; and basic design, connection and standards of current and voltage instrument transformers for protection and metering applications.

Subject objectives/outcomes

The primary objective of this subject is the development of a working knowledge of power systems operation and protection. The subject aims to provide students with a knowledge and understanding of:

• elements of the supply chain and how they function in the National Electricity Market
• demand-side management options including smart meters
• load forecasting and optimal load scheduling for secure energy supply and use
• protection schemes for transmission and distribution networks
• communications in power systems, including communication media, architectures, automation, standards, protocols and security
• basic design, connection and standards of current and voltage instrument transformers for protection and metering applications

Subject Objective
Power system operation and protection are two important areas in the power system management. This subject is intended to cover the different aspects of power system operation and protection. The subject will provide the students with the basic knowledge about the various protection methodologies used in power system and also the power system operating principles. The subject aims to cover the following:

1. Instrument transformers and power system protective relaying.
2. Protective schemes for generators, transformers and transmission lines.
3. Principles of current interruption and circuit breakers.
4. Concepts of power system planning.
5. Fundamentals of economic operation of power system.
6. Functioning of power system markets.
7. Operation and control of power systems.

Contribution to course aims and graduate attributes

• gaining skills and experience in an interdisciplinary practice of engineering
• gaining experience in self-directed learning and research
• carrying out major engineering projects which require both theoretical and practical competencies

Teaching and learning strategies

Class time is used for lectures, tutorials, and laboratories. Lectures will introduce material in a modular fashion, starting from electricity supply chain fundamentals and working up to power system operation and protection scheme design. Tutorials will concentrate on reinforcing fundamental concepts through drill problems, computer simulations and design exercises. Laboratories will reinforce fundamental concepts and provide opportunities for verification of power system behaviour from model predictions. In order to bridge the gap between theory and practice and to increase familiarity with the literature, students will be required to attempt a number of computing and experimental assignments based on theory and techniques treated in the lectures, but which require further individual investigation.

Apart from lectures and laboratory sessions scheduled in the course time table, the course will comprise of 4 in class assessment tasks, 2 home work assignments and 1 mid-semester exam. Students are expected to actively participate in assessment tasks.

The lecture notes are aimed as a supplement to the text books referred by the students. Students are advised not to depend only on the lecture notes but to work through the prescribed text books as well as other published texts on the topic using the notes as a guideline. The text books contain many examples and exercises. Although solving these exercises is not formally assessed, this work is part of the learning process. The students are expected to enhance their competency in the course by solving these exercises and to demonstrate their level of understanding through the laboratory work and solving exam problems and assessment tasks.

Lectures
Students are strongly advised to attend all lectures. Lecture attendance will be recorded.Lectures will be delivered in an interactive atmosphere between the students and the lecturer. Students will have the opportunity to raise any doubts and questions in relation to the lecture topic. Tutorial questions relevant to the lecture topics will be solved along with the lecture on the topic. Tutorial solutions will not be provided online. Students are encouraged to work through exercise problems relevant to the lecture topics included in the power system text books.

In class assessment tasks
In class assessment tasks will be based on the topics covered in the past lectures. These tasks are aimed to ensure the student’s regular update of the topics covered in the lectures. The dates for these tasks will not be announced in advance and will be conducted randomly during the regular lectures. The tasks are individual activities and will be conducted in a class test environment. Re-assessment tasks will not be given to the students who miss a particular in-class assessment task.

Labs
Laboratories are structured sessions that allow you to put into practice the theory developed in lectures using specialised equipments. They generally involve pre-work. Students should complete any prelab work included in the experiment before coming to the lab. Experienced laboratory staff will assist in the running of the laboratories. The power system laboratories will include experiments that may involve high voltages hence the students have to strictly adhere to the safety procedure and the safety instructions given by the lab staff members.

Content

The subject is structured into four modules, and content is organized as follows:

1. Electricity Supply Chain Fundamentals, Demand-Side Management and Load Forecasting: overview of the National Electricity Market (NEM), and the roles of the various participants in planning and operating the supply and delivery of energy to the end user; market security operations; market financial operations; and demand-side management and load forecasting.
2. Protection of Transmission and Distribution Networks: Abnormal conditions; protection functions; protection system elements (DC tripping circuits, primary protection and zone overlapping, back-up protection); protection requirements (reliability, dependability, security, selectivity, speed, sensitivity, simplicity, economics); design and operation of fuses, relays, circuit breakers, surge diverters; and overvoltage, overcurrent, unit, distance, transformer, bus and auto-reclose protection schemes.
3. Instrument Transformers and Protection Settings: current transformers, magnetic voltage transformers, capacitive voltage transformers; protection drawings; protection settings process; feeder protection settings; transformer protection settings; and backup earth fault and overcurrent protection coordination.
4. Telecommunications and Communications Protocols: Communication principles and terminologies used in power systems; leading global organisations and their standards; power system automation and integration concepts; architectures and protocols utilised in power system communication networks; power system security aspects, SCADA and contingency analysis; operational metering; and future technologies and their implications for power system communications.

Instrument transformers
Current transformers - Vector diagram - CT Definitions - Magnetisation curve of a CT – Transient behaviour of CTs - Potential transformers (PTs) - Vector diagram of a PT - CT Definitions

Protective relays
Requirements of a protective relaying - Classification of relays - Induction relay - Torque equation of the induction relay - Characteristics of induction relay - Directional relay - Torque in directional element - Distance relays - Impedance relay - Mho relay Static relays - Static overcurrent relay - Micro-processor based relays - Microprocessor over current relay

Protection of generators
Differential protection - Problems with differential protection - Biased differential protection - Biased differential protection of generator - Over current and earth fault protection

Protection of transformers
Buchholz relay - Biased differential protection of transformers - Harmonic restraint – Harmonic blocking - Other transformer protections

Protection of transmission lines
Time graded overcurrent protection - Protection of ring main systems - Distance protection of transmission lines - High speed impedance protection - Differential pilot wire protection of transmission lines - Transley protection of transmission lines - Carrier current protectionCircuit breakers
Arc phenomena - Recovery rate theory - Energy balance theory - Recovery and restriking voltages - Rate of rising of restriking voltage (RRRV) - Resistance switching - Interruption of capacitive and inductive circuits - Capacitive circuits interruption - Inductive circuits interruption and current chopping - Circuit breaker classifications and specifications - Oil circuit breakers - Plain break oil circuit breaker - Self generated pressure oil circuit breaker - Air blast circuit breaker - Sulphur hexa-fluoride (SF6) circuit breaker - Vacuum circuit breaker - Selection of circuit breakers - Gas insulated substation (GIS) - Gas insulated cables (GIC)

Power system planning
Aspects of power system planning - Stages of power system planning . - Basic planning stage - System development stage - Project planning stage - Load forecast - Terminologies - Load curve - Load forecast methods - Planning principles
Economic operation of power system
Power output control between units within a plant - Load distribution between different plants - Computation of transmission line loss - Economic dispatch with transmission losses included

Operation and control of power systems
SCADA / EMS - Remote terminal units (RTU) - Real time and study mode activities – Basic SCADA / EMS architecture - System operating states - State estimation - Power system operation under NEMCO - Security analysis by NEMCO - Dynamic security assessment (DSA)

Power markets
Different marketing companies - Characteristics of electricity market - Spot marketing – Balanced spot market - Functioning procedure of spot market management - Payment process - Economic operation - Condition for optimal generation - Scheduling - Security of power system operation - Generation-load balance - Network security - Implementation of ancillary service mechanism - Compulsory ancillary services - Ancillary services from market - Ancillary services from load end - Ancillary service purchase - Estimation of ancillary service requirement - Billing of ancillary services - Payments for reserve services - Payments for regulation and load following services.

Assessment

Assessment Item 1: 3 Laboratory exercises

Assessment Item 2: Assignment - 1

Assessment Item 3: Assignment - 2

Assessment Item 4: Assignment - 3 (individual activity)

Assessment Item 5: Class Test

Minimum requirements

The overall minimum mark required to pass the subject is 50%.

Recommended texts

Y. G. Paithankar and S. R. Bhide , Fundamentals of Power System protection, Prentice-Hall of India, Second Edition, 2010.

Daniel Kirschen and Goran Strbac, Fundamentals of Power System Economics, John Wiley & Sons, Ltd, 2004.

References

A. Wright and C. Christopoulos , Electrical power system protection, Chapman & Hall,
1993.
Robert H. Miller and James H. Malinowski , Power system operation, McGraw-Hill, 1993.
Jurgen Schlabbach and Karl-Heinz Rofalski , Power system engineering,Wiley-VCH Verlag
GmbH & Co. KGaA, 2008.
John J. Grainger and William D. Stevenson, Jr., Power system analysis, McGraw-Hill, Inc,.
Hadi Saadat, Power system analysis, McGraw-Hill Primis custom publishing.

Since the subject covers wide topics, it is hard to recommend list of books covering the entire subject. Students are advised not to restrict themselves to the above mentioned text books but to refer books in the power system discipline to widen their knowledge in the subject.

Other resources

UTSOnline provides a subject web site with notes in PDF format and links to on-line resources etc.

Twenty four hour access to computer laboratories that have MATLAB will be given to the students.

It is important for the students to visit http://online.uts.edu.au regularly as important course announcements, lecture notes, lab handouts and assignment sheets will be posted in UTS Online.

Student Guide