Diagnostics and electrical equipments protections
FEKT-NDJZAcad. year: 2019/2020
Faults and protections against overcurrents in electrical equipments. Protective devices and their characteristics. Protection of cables and wires aganist overloads and short circuits. LV motors and generators protection. Protectin devices for transformers, capacitancies, batteries etc. Usage of switchgears in switgear assemblies. Protection of semiconductors. Overvoltage protection devices. Protection against electric shock, residual current devices.
Learning outcomes of the course unit
Students can describe:
- principal of function of various protective devices
- principals of protection against overcurrents for individual kinds of devices
- principals of selectivity determination
- principals of protection against electric shock
- principals of overvoltage protection
Students can explain
- meaning of parameters of protective devices
- phonemena influencing design of protection for electric devices
- kinds of selectivity between protective devices
- principals of individual protective provisions for protective measure automatic disconnection of supply
- overvoltage origin and protection against it
Students are able to design
- cables protection against overload and short circuit
- protection of motors and inlets to them
- protection of transformers
- protection of semiconductors
- protection of capacitive bateries
- selectively connected protection devices in series
- electric circuit from the automatic disconnection of supply point of view
- individual levels of overvoltage protection
Students are able to analyse
- effects influencing protection of electric devices
- effetcts of short-circuit currents
- appropriate usage of protective devices
Students are able to judge
- correctness of overcurrent protection of electric devices
- selectivity between protective devices
- protection of surge arrestors
- fulfillment of conditions for protective measure automatic disconnection of supply
Students are able to compose
- report concerning protection of electric devices
- protocol on short circuit calculation
- protokol on measurement of important parameters of protective devices
The subject knowledge on the Bachelor´s degree level is requested.
- to solve electrical circuits by the method of circuit simplification and nodes potentials
- knowledge of electrodynamic forces effects and calculation
- knowledge of thermal effects of electric currents in steady state and during transient period
- calculation of short-circuit currents in LV networks
- classification of electrical switching devices based on the ability to switch various currents
- phonemena during motor start
- function of a transformer
- knowledge of regulation 50/1978 Sb.
Recommended optional programme components
Recommended or required reading
Tříska J.:Jištění,SNTL 1962 (CS)
Franken:Jištění elektromotorů,SNTL (překlad z něm. j.) (CS)
Havelka a kol.:Elektrické přístroje,SNTL 1985 (CS)
Bašta a kol.: Měření na elektrických strojích, SNTL 1959 (CS)
Heumann, G. W.: Overload Relays and Circuit Breakers for Protecting Motorized Appliances and Their Branch Circuits (EN)
T.E. Browne, jr.: Circuit interruption, New York, 1984 (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.
1. Lectures on each subjects (P1-P13).
2. Lectures are practised during numerical, computer and laboratory tasks every week.
3. All texts are available in faculty system.
Assesment methods and criteria linked to learning outcomes
exam - 70 points
test and practice - 30 points
Language of instruction
1. Kinds and origin of faults in electric devices
2. Parameters and characteristics of fuses
3. Parameters and characteristics of circuit breakers and other protective devices
4. Wires protection against overload
5. Calculation of short-circuit currents and wires protection against short-circuit currents.
6. Motor and motor inlets protection
7. Transformer protection
8. Protection of semiconductors and other devices
9. Protection of capacitor bateries, usage of switchgears in switchgear assemblies
10. Selectivity between protective devices
11. Protection against electric shock
12. Protection against overvoltage
Students will understand characteristics of electrical protective devices and their usage for protection of individual types of electrical devices.
Specification of controlled education, way of implementation and compensation for absences
The content and forms of instruction in the evaluated course are specified by a regulation issued by the lecturer responsible for the course and updated for every academic year.