400 kVA transformer for powering the substation’s own needs
Students Name: Shatkovskyi Denys Volodymyrovych
Qualification Level: magister
Speciality: Electrical Energetics, Electrical Engineering and Electromechanics
Institute: Institute of Power Engineering and Control Systems
Mode of Study: part
Academic Year: 2023-2024 н.р.
Language of Defence: ukrainian
Abstract: The object of research of this qualification work is the process of electromagnetic conversion of electrical energy of one voltage into electrical energy of another voltage. The subject of research is an oil-filled power transformer. The purpose of the work is to calculate and design a three-phase oil-filled transformer for long-term operation. In the first chapter of the master’s qualification work, the principle of operation, the structure of three-phase power transformers, the types of their magnetic conductors, windings, an overview of modern designs and cooling methods are considered [1]. In the second section, an acceptable design is selected that corresponds to the given task [2]. The substantiation of the adopted design decisions regarding the design of the magnetic circuit, transformer windings and its cooling arrangement has been completed. The third section is devoted to performing an electromagnetic calculation [2, 3], in which the main dimensions of the transformer are calculated, the types of primary and secondary windings are selected, the cross-sectional dimensions of the winding conductors are selected, the type of charging joints is selected, and the sizes of the cores and yokes of the magnetic conductor are calculated. The calculation of the magnetic circuit, short-circuit losses in steel was carried out, the short-circuit voltage and ultimate forces in the windings were calculated. In the fourth section, thermal calculations were performed, the temperature difference of HV and LV windings, tank walls, and oil relative to the temperature of the outside air was determined. The cooling system, the dimensions of the smooth tank, the type and dimensions of radiators for oil cooling are calculated [2]. In the fifth section, the parameters of the electrical substitute circuit of the transformer are calculated. The operating characteristics of the transformer were calculated and constructed - the efficiency factor of the transformer depending on the value of the load current for the active, inductive and capacitive nature of the load; change in the secondary voltage of the transformer at nominal load as a function of the load angle; dependence of the output voltage of the transformer on the load current (external characteristics) for different types of load. Key words: three-phase power transformer, low-voltage winding, high-voltage winding, efficiency, no-load losses, short-circuit losses, short-circuit voltage, transformation ratio, substitution circuit, copper losses, steel losses, oil-filled transformer, operating characteristics transformer, the nature of the load. Referenses: 1. Електричні машини: підручник / М. А. Яцун ; Нац. ун-т «Львів. політехніка». – Л. : Вид-во Львів. політехніки, 2011. – 461, с. 2. Расчет трансформаторов: Учеб. пособие для вузов. - 5-е изд., перераб. и доп. - М.: Энергоатомиздат, 1986. - 528 с. 3. Розрахунок і проектування трифазних трансформаторів. Курсове проектування : навчальний посібник / Левицький С. М., Бальзан І. В., Шевчук Ю. В. – Вінниця : ВНТУ, 2018. – 127 с.