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Failures and Protection of Electrical Networks

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Course Unit Code410-2317/01
Number of ECTS Credits Allocated6 ECTS credits
Type of Course Unit *Compulsory
Level of Course Unit *First Cycle
Year of Study *Third Year
Semester when the Course Unit is deliveredSummer Semester
Mode of DeliveryFace-to-face
Language of InstructionCzech
Prerequisites and Co-Requisites Course succeeds to compulsory courses of previous semester
Name of Lecturer(s)Personal IDName
MED40doc. Dr. Ing. Zdeněk Medvec
Summary
The subject includes theoretical part of extraordinary states in electric systems. It follows short-circuit in network and ground connection in electric systems. The subject explains basic terms of electromechanical transient effects in electric systems. The subject includes theoretical part of protections and automatics in electric power distribution. It follows line protections, transformer protections and anti-breakdown automatics. The subject explains basic terms, principles and functions of electromechanical, transistor and digital protections.
Learning Outcomes of the Course Unit
Explaining basic terms and principles of electromechanical transient effects in electric systems. After passing the subject the student is able to calculate symmetric and asymmetric short-circuit in network, ground connection in electric systems and static and dynamic stability of system. The student is also able to practise dimensioning of electric equipment according to effects of short-circuit currents. Explaining basic terms, principles and functions of electromechanical, transistor and digital protections. After passing the subject the student is able to apply the theory of protections and automatics in electric power distribution into the design of protection systems.
Course Contents
Lectures:
1. Definition and distribution of transient effects.
2. Calculation of short-circuit currents in complicated electric systems.
3. Characteristic values of short-circuit in general network. Parameters of elements of electric system in symmetrical systems.
4. Asymmetrical operating status of electric system. Dimensioning of electric equipment according to effects of short-circuit currents.
5. Ground connection in electric systems.
6. Basic terms of protections, operation of protections. Basic elements of protections, electromechanical and statical relays.
7. Line protections. Over-current protections, short-circuit protections, directional over-current protections.
8. Line protections. Distance (impedance) protections.
9. Line protections. Transverse and lengthwise differential protections.
10. Transformer protections. Differential protections. Frame-leakage protections, Buchholz protection.

Exercises:
1. Information about the requirements for passing the exercises. Safety considerations. The organization of the work in the labs. Instructions for elaboration of lab task.
2. Calculation of short-circuit currents according to ČSN EN 60909.
3. Calculation of symmetric and asymmetric short-circuit currents.
4. Dimensioning of electric equipment according to effects of short-circuit currents.
5. Calculation of ground connection in electric systems.
6. Setting of line over-current protections, Setting of transformer protections.
7. Laboratory electrical measurement of short-circuit currents at model.
8. Laboratory electrical measurement at digital protection.
9. Setting of line impedance protections.
10. Credit exercise.

Projects:
Calculation of symmetric short-circuit currents
Calculation of asymetric short-circuit currents
Recommended or Required Reading
Required Reading:
1. Blackburn, J. Lewis: Protective relaying-principles and applications. Marcel Dekker, Inc., New York, 1998.
2. Horowitz, S. H., Phaddke, A. G.:Power system relaying. RSP Press Ltd. Tauton, 1992.
1. Trojánek Z., Hájek J., Kvasnica P.: Přechodové jevy v elektrizačních soustavách, SNTL/ALFA 1987.
2. Medvec Z.: Přechodové jevy v elektrizačních soustavách. Návody do cvičení. Skriptum VŠB-TU Ostrava, 2001.
3. Janíček, F., Chladný, V. a kol.: Digitálne ochrany v elektrizačnej sústave. STU Bratislava, 2004.
4. Haluzík E.: Ochrany automatiky v elektrických sítích. Skripta VUT Brno 1985.
Recommended Reading:
1. Machowski, J., Bialek, J.W., Bumby, J.R.: Power system dynamics and stability. Wiley, 1997.
2. 1. Anderson, P.M., Fouad, A.A.: Power system control and stability. Iowa, 1977.
3. Sleva, A. F.: Protective relay principles. CRC Press, 2009, ISBN 978-0-8247-5372-6.
1. Dohnálek P.: Ochrany pro průmysl a energetiku, SNTL Praha 1991.
2. Dohnálek P.: Technika ochran. SNTL Praha 1989.
3. ČSN 333051 - Ochrany elektrických strojů a rozvodných zařízení.
4. ČSN EN 60909-0. Zkratové proudy v trojfázových střídavých soustavách. Květen 2002.
Planned learning activities and teaching methods
Lectures, Tutorials, Experimental work in labs, Project work, Other activities
Assesment methods and criteria
Task TitleTask TypeMaximum Number of Points
(Act. for Subtasks)
Minimum Number of Points for Task Passing
Exercises evaluation and ExaminationCredit and Examination100 (100)51
        Exercises evaluationCredit40 20
        ExaminationExamination60 11