Electrical Equipment and Insulations

Week 1: Categorization of electric switchgears and apparatus, their role in the low, medium and high voltage networks and their functions in the operation of substations. Duties of electrical insulation in apparatus and stresses affecting them. Operation phases of switchgears and calculation of their load.

Week 2: Discharges in gaseous insulation. Basic properties of the electric arc, its quenching and behaviour as a circuit element. Goals and methods of electric arc protection. Properties of sulphur-hexafluoride gas as an arc quenching medium.

Week 3: Construction and operation of sulphur-hexafluoride circuit breakers and metal-clad switchgear. Construction and operation of medium and low voltage circuit breakers and fuses. Apparatus of the medium voltage overhead distribution network.

Week 4: Aspects of the selection of electrical apparatus. Types of low voltage switches and their role in the electrical supply of homes, offices and industrial facilities. Standards related to building electrification.

Week 5: Basics of electrical design. Phases of design and the required documentation. Standard symbols.

Week 6: Physical processes in insulation at low electric field: conduction and polarization.

Week 7: Physical processes in liquid and solid insulation at high electric field: breakdown and flashover.

Week 8: Duties and stresses of insulation. Coordination of insulation levels.

Week 9: Construction and operation of overvoltage protecting devices.

Week 10: Basics of design on electrical stress. Economic use of insulation. Potential control.

Week 11: Insulation of transformers and the applied insulating materials. Insulation of rotating machines and the applied insulating materials. Construction of high voltage current and voltage transformers and their insulation system.

Week 12: Construction and insulation of overhead lines and the applied insulating materials. Construction of cables and the applied insulating materials.

Week 13: Generation and measurement of high voltage – DC, AC and aperiodic voltage impulse, high frequency and damping impulse.

Week 14: Basics of standard commissioning tests of electrical apparatus, electrical commissioning tests.

Calculations in the following topics:

Loads of switchgear. Switch-on transients and let-through current calculation at DC and AC voltage. Transient recovery voltage calculation in case of short circuit at the busbar, on the network and in the dangerous zone. Calculation of electrical stress in the most common insulation arrangements.