The power quality and EMC
FEKT-NPQ1Acad. year: 2015/2016
The power quality is characterized by the steady-state sinewave voltage of nominal parameters (magnitude and frequency) more over symmetrical in the three-phase system. The power quality depends on quality of electrical power generation, of transmission and distribution as well as on quality of electrical power consumption. Disturbances of the individual power system components and their compatibility and cooperation in an industrial and distribution networks are the content of this course. Disturbance mechanisms are demonstrated on practical examples. More over there are discussed techniques and actions leading to mitigation of consequences and providing electromagnetic compatibility in the field of low-frequency disturbances. At least the course is aimed to measurement instruments and algorithms description and voltage quality evaluation.
Learning outcomes of the course unit
Student is able to:
- explain origin of chosen low-frequency disturbances,
- identify low-frequency conducted disturbance sources,
- describe cases of electromagnetic interference,
- quantify consequences and affects,
- describe propagation of low-frequency conducted disturbances in principles,
- discuss general mechanisms to ensure electromagnetic compatibility,
- specify rules, methods, techniques and devices for mitigation of causes and consequences of electromagnetic interference in the field of low-frequency conducted disturbances,
- name measurement procedures of voltage quality characteristics,
- describe voltage quality characteristics in detail,
- define voltage (power) quality according to the current standards,
- select appropriate measurement instruments in order to perform power network analysis and voltage quality monitoring.
General knowledge in electrical power engineering is expected, especially in the field of electrical power distribution, power electronics and converters, measurement and signal processing theory, respectively. In general, the subject knowledge on the Bachelor´s degree level is requested.
Recommended optional programme components
Recommended or required reading
Current EMC standards (EN, IEC, IEEE, ANSI, CISPR). (EN)
RYAN, M., ET AL. POWER QUALITY: Reference guide. Hydro Ontario, Canada, 1996, 6th edition, 130 pp. (EN)
BOLLEN, H.,J. Understanding Power Quality Problems. Voltage Sags and Interruptions. IEEE Press, John Wiley and Sons, ISBN 0-7803-4713-7 (EN)
Dugan, R., et al. Electrical power systems quality. McGraw-Hill, 2003, ISBN 0-07-138622-X (EN)
Arrillaga, J., Watson, N.,R. Power System Harmonics. Wiley, 2003, ISBN 0-470-85129-5 (EN)
Planned learning activities and teaching methods
Teaching methods depend on the type of course unit as specified in the article 7 of BUT Rules for Studies and Examinations. Techning methods include lectures, numerical exercises, homeworks and computer and practical laboratories. Course is taking advantage of e-learning (Moodle) system.
Assesment methods and criteria linked to learning outcomes
There are evaluated of laboratory exercises, exercises on PC, homework and final exam according to the rules of FEEC. Laboratory training is rated at maximum of 30 point on the basis of submitted records, whereas 15 points is the minimum for admission to final exam. As for the exercises on PC and homework evaluation, at maximum 5 points can be achieved in both cases. The final exam is of oral form, where 60 point can be acquired maximally and successful pass is conditional on obtaining 20 points at minimum.
Overall classification of the course is in compliance with the FEEC rules. Requirements for completion of the course are specified by a regulation issued by the lecturer responsible of the course and are updated for every year.
The final exam is aimed at understanding in the field of power quality in supply, mechanisms and sources of low-frequency conducted disturbances, electromagnetic compatibility of power systems including principles and techniques to ensure mutual compatibility of electrical appliances and power network and of voltage quality indicators measurement and evaluation.
Language of instruction
Electromagnetic compatibility of power systems, definition and relevance of EMC, compatibility levels, power and voltage quality.
Fundamental Czech, European and international legislative.
Distribution of the disturbance types, summary of backward disturbing influences of electrical appliances to the supply network.
Harmonic distortion. Definition, description, sources, calculations.
Harmonic components propagation, frequency response characteristics of power networks, resonances.
Harmonics presence consequences, Influence on power system apparatus, Voltage distortion.
Measurement of harmonics, compatibility levels, EMC in term of harmonics, harmonics mitigation.
Interharmonic and subharmonic components. Definition, description, origin, sources, consequences, compatibility levels and EMC in terms of interharmonics.
Voltage magnitude and slow changes. Description, mechanism of changes, compatibility level, voltage profiles and their time variations, voltage regulation techniques.
Voltage fluctuations and rapid changes. Definition, description, origin, disturbing effect – lamps flickering, flicker severity measurement.
Voltage fluctuation propagation, compatibility levels, ensuring EMC in terms of voltage fluctuation, voltage fluctuation and lamps flickering mitigation techniques.
Voltage asymmetry. Definition and description, origin and sources, measurement, compatibility level, providing EMC, mitigation techniques.
Voltage events (swells, dips and interruptions). Definition, description and classification, origin, measurement and evaluation.
Voltage events propagation, consequences, immunity of electrical appliances, mitigation techniques and their coordination.
Voltage characteristics. EN 50 160.
Power network analyzers, voltage monitors. Measurement of low-frequency conducted disturbances; voltage and current transducers.
Aim of the course is to apprise students of power systems electromagnetic compatibility, disturbance types and sources with their backward disturbing influences to power network systems, measurement of low frequency conducted electromagnetic disturbances and related power quality and of ways to providing electromagnetic compatibility in terms of all related disturbances.
Specification of controlled education, way of implementation and compensation for absences
The content and forms of course units are specified by a regulation issued by the responsible lecturer and are updated for every academic year. In general, the presence at class is optional except laboratory training, which is mandatory. Missed laboratory training can be accomplished within semester in an alternative date in justified cases, whereas regular letter of apology and agreement with the teacher is required.
Type of course unit
26 hours, optionally
Teacher / Lecturer
2 hours, optionally
Teacher / Lecturer
4 hours, compulsory
Teacher / Lecturer
20 hours, compulsory
Teacher / Lecturer