20.500.12556/RUL-184027 Model za izračun kratkostičnih izgub v energetskem transformatorju Model for calculating short-circuit losses in a power transformer Transformator je elektromagnetna naprava, ki prenaša električno energijo med različnimi napetostnimi nivoji. Med prenosom nastajajo izgube, ki povzročajo segrevanje in zmanjšujejo izkoristek transformatorja. Kljub visokim izkoristkom proizvajalci stremijo k nadaljnjemu zmanjšanju in obvladovanju izgub. Ohmske izgube in izgube v magnetnem jedru so relativno dobro določljive, večja negotovost pa ostaja pri izgubah v ostalih delih transformatorja, tako imenovane dodatne izgube. Čeprav te običajno prispevajo majhen delež k skupnim izgubam, njihovega vpliva ne smemo zanemariti, saj lahko povzročijo lokalne vroče točke in s tem vplivajo na delovanje transformatorja. V prvem delu naloge je izvedena podrobna analiza izbranega tipa transformatorja. Obravnavani so aktivni deli in ključni konstrukcijski elementi: magnetno jedro, navitja, jarmske in stebrne letve, magnetni zasloni ter transformatorski kotel. Za vsak element so opredeljeni konstrukcijski parametri in specifične materialne lastnosti, ki so ključni za izdelavo natančnega numeričnega modela. Poseben poudarek je namenjen analizi nastanka dodatnih izgub v konstrukcijskih elementih in navitjih. Na podlagi ugotovitev analize prvega modela je bil v drugem delu zasnovan poenostavljen model, namenjen napovedovanju izgub transformatorja v fazi načrtovanja. Ohmske izgube navitij so izračunane analitično na podlagi parametrov transformatorja, medtem ko so izgube v vezeh ocenjene s pomočjo novo razvite semiempirične enačbe. Vrtinčne izgube v navitjih so določene analitično na podlagi 3D magnetnega polja. Izgube v ostalih prevodnih elementih so določene s 3D modelom, ki vključuje glavne komponente: kotel, stebrne in jarmske letve ter magnetne zaslone. Rezultati poenostavljenega modela so verificirani z izmerjenimi vrednostmi, na podlagi česar je bila določena metoda z največjo natančnostjo za napoved kratkostičnih izgub. Metodološki del vključuje definicijo materialnih lastnosti, generiranje mreže končnih elementov in robnih pogojev v okolju Ansys Maxwell 3D. Električne in magnetne karakteristike komponent so povzete po programski knjižnici in specifikacijah materialov. Poleg tega so podani: izračun vdorne globine za zajetje vrtinčnih tokov, konfiguracija kvazistatičnega reševalnika in način vzbujanja navitij. S takšno postavitvijo modela je omogočena numerična evalvacija ohmskih in dodatnih izgub, kar predstavlja podlago za validacijo modela s primerjavo z meritvami kratkega stika. A transformer is an electromagnetic device that transfers electrical energy between different voltage levels. During this transfer, losses occur which cause heating and reduce overall efficiency. Despite high efficiencies, manufacturers strive for further reduction and control of losses. While ohmic and core losses are relatively well-defined, a higher degree of uncertainty remains regarding losses in other transformer components, known as stray losses. Although these typically represent a small fraction of total losses, their impact must not be neglected, as they can cause local hot spots and consequently affect the transformer's operation. The first part of the thesis involves a detailed analysis of a selected transformer type. The active parts and key structural elements are addressed, including the magnetic core, windings, yoke and limb clamps, magnetic shields, and the transformer tank. For each element, structural parameters and specific material properties are defined, which are crucial for the development of an accurate numerical model. Special emphasis is placed on the analysis of stray loss generation within the structural components and windings. Based on the findings from the initial model analysis, a simplified model was designed in the second part of the work, intended for predicting transformer losses during the design phase. Winding ohmic losses are calculated analytically based on transformer parameters, while losses in the connections are estimated using a newly developed semi-empirical equation. Winding eddy current losses are determined analytically based on the 3D magnetic field. Losses in other conductive elements are determined using a 3D model that includes the main conductive components: the tank, limb and yoke clamps, and magnetic shields. The results of the simplified model were verified against measured values, based on which the most accurate method for predicting load losses were determined. The methodological section includes the definition of material properties, the generation of the finite element mesh, and the setup of boundary conditions in the Ansys Maxwell 3D environment. The electrical and magnetic characteristics of the components are derived from the software library and material data sheets. Furthermore, the skin depth calculation for capturing eddy currents, the configuration of the eddy current solver, and the winding excitation method are presented. This model setup enables an accurate numerical evaluation of ohmic and stray losses, providing a basis for model validation through comparison with load losses measurements. kratkostične izgube dodatne izgube transformatorja model za napoved izgub transformatorja energetski transformator magisteriji load losses transformer stray losses transformer load-loss prediction model power transformer true false false K. Plevnik Slovenski jezik Angleški jezik Magistrsko delo/naloga 2026-06-24 08:40:00 2026-06-24 08:40:17 2026-06-25 04:12:12 0000-00-00 00:00:00 2026 0 Ljubljana 2026 Ljubljana 1 spletni vir (1 datoteka PDF (XVI, 83 str.)) 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 621.314.2 (043.3) 63289 282723843 Plevnik_Klemen_-_Model_za_izracun_kratkosticnih_izgub_v_energetskem_transformatorju.pdf Plevnik_Klemen_-_Model_za_izracun_kratkosticnih_izgub_v_energetskem_transformatorju.pdf 1 F8EC18A0578CD9233F200E80AB2B499E 8f6f04b81aa700d48925df17bb4dfa9d292372450e3ad24748b6e93ee1c26d59 7b9e6e19-6f97-11f1-9b0d-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=236471 Fakulteta za elektrotehniko 0 0 0