“Investigation of the partial discharge in high voltage electric machines” Doctoral Thesis

Author, institution: Gediminas Daukšys, Kaunas University of Technology

Science area, field: Technological Sciences, Energetics and Power Engineering

The Doctoral Dissertation is available at the libraries of Kaunas University of Technology (K. Donelaičio g. 20, Kaunas) and Lithuanian Energy Institute (Breslaujos g. 3, Kaunas)

Scientific Supervisor: Assoc. Prof. Dr. Audrius JONAITIS (Kaunas University of Technology, Technological Sciences, Energetics and Power Engineering – 06T).

Board of Energetics and Power Engineering science field:
Dr. Antanas MARKEVIČIUS (Lithuanian Energy Institute, Technological Sciences, Energetics and Power Engineering – 06T) – chairman;
Prof. Habil. Dr. Juozas AUGUTIS (Vytautas Magnus University, Technological Sciences, Energetics and Power Engineering – 06T);
Prof. Dr. Algirdas BAŠKYS (Vilnius Gediminas Technical University, Technological Sciences, Electrical and Electronics Engineering – 01T);
Prof. Habil. Dr. Gintautas MILIAUSKAS (Kaunas University of Technology, Technological Sciences, Energetics and Power Engineering – 06T);
Dr. Egidijus URBONAVIČIUS (Lithuanian Energy Institute, Technological Sciences, Energetics and Power Engineering – 06T).

Official opponents:
Assoc. Prof. Dr. Saulius LISAUSKAS (Vilnius Gediminas Technical University, Technological Sciences, Electrical and Electronics Engineering – 01T);
Prof. Habil. Dr. Stasys ŠINKŪNAS (Kaunas University of Technology, Technological Sciences, Energetics and Power Engineering – 06T).

Annotation:

The most important factor which ensures qualitative and economic work of all electrical energetics system is the insulation condition of electrical equipment in electrical energetics system. Reliable operation of electrical equipment depends on proper exploitation of the equipment and status monitoring, well-timed maintenance, factors influencing the equipment and their nature.
Insulation condition and reliable working hours for the high voltage electrical equipment depend on the various factors in electrical energetics system: overvoltages, partial discharges, overcurrents. Those factors also influence HV electric machines used in electric power stations and enterprises. The various faults are found in them because of strong electric field, overvoltages, discharges, thermal influence, moisture, oxidation, vibration, aging processes and other factors. Overvoltages, raising of the temperature and partial discharges have the biggest influence on the insulation condition and showing of faults. Overvoltages‘ influence duration and amplitude may be various in the electrical energetics system. Overvoltages and operational temperature of the equipment are the main factors which accelerate the ageing processes of electric machines insulation.
In this paper, analyzed, summarized and presented methodology allows to evaluate the insulation state of working high voltage electric machines and to optimally plan repair work of equipment insulation