LEARNING OUTCOMES

To know the technological solutions for the construction of electrical apparatuses both from the morphological point of view as well as from the functional one. To know how to set the preliminary design of static electric machines.

AIMS AND LEARNING OUTCOMES

To provide the elements on the morphology of electrical equipment for low, medium and high voltage. To provide the elements for the preliminary design of static electric machines.

SYLLABUS/CONTENT

: References to the principles of operation of electrical machines. Dimensional relationships for electrical machines.       Main aspects of a project. Design constants of transformer machine.    

                General information on the cooling systems of electromechanical components. References to mathematical cooling models relevant to irradiation, conduction and convection. transients. Study of the continuous, limited and intermittent service. Service with variable loads.

Morphology, technological and design problems of transformers and coils. Outline of transformers. Typology, market situation, safety problems. Structure of dry and resin-based transformers. Structure of oil transformers. Types of insulating liquids. Cooling criteria with varying power. Accessories. Morphology of magnetic cores, stepped cores, oriented crystalline magnetic sheets. Morphology and problems related to BT, MT and AT windings. Isolation systems. Coils in foil, round wire and rectangular wire. Transposition of conductors. Methods of calculation of the magnetic circuit and of the windings. Calculation of dispersion reactance in the case of different types of winding. Short-circuit behaviour of radial and axial electrodynamic forces. Determination of the equivalent circuit, of the losses and of the no-load current. Additional losses. Overvoltage in components and plants and their classification. Circuits for impulse tests. Methods to withstand overvoltage in MT and AT transformers. Behaviour of transformer AT windings in the presence of overvoltage and use of screens.

Preliminary design of a transformer for MT: electromagnetic sizing and verification calculations.

Reactances in the air and with a core of ferromagnetic material, application criteria and dimensioning schemes.

Surge Protective Devices. Type of construction. Silicon carbide and zinc oxide SPDs. Dimensioning and use criteria and technological problems.

Classification of interruption equipment. Type of beakers BT, MT, AT depending on the arc interruption  and control type. Morphology and technological problems in the air, vacuum, in SF6. Limiter breakers. Breakers with interruption chambers in series with partitioning capacitors. Integrated systems for MT and AT in SF6 live and dead tank.

Switch-Disconnectors. 

Disconnectors.

Contactors.

Fuses. Types and characteristics of use. Constructive morphology.

Gas insulated systems in SF6. Cost and benefit assessment based on equipment costs and environmental impact problems. Morphology of GIS. Technological problems and insulating systems.

RECOMMENDED READING/BIBLIOGRAPHY

Notes of the Course

Costruzione delle Maccchine Elettriche, Giovanni Someda, editore Patron

Costruzioni Elettromeccaniche, Enrico di Pierro, editore Siderea