Izračun napona kratkoga spoja transformatora primjenom konformnih preslikavanja

doctoral thesis

• Title (english): Calculation of transformer short-circuit voltage using conformal mappings
• Author: Mario Jurković; MBZ: -331116
• Mentor: Damir Žarko (mentor)
• Committee member: Damir Žarko (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; (Department of Electric Machines, Drives and Automation); Zagreb
• Defense date and country: 2021, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering
• Universal decimal classification (UDC): 621.3 - Electrical engineering

Abstract

U doktorskom radu predstavljena je metoda za izračun napona kratkog spoja transformatora primjenom konformnih preslikavanja. Prostor unutar prozora jezgre te prostor izvan jezgre u uzdužnom presjeku i poprečnom presjeku preslikavaju se u prostor unutar jediničnog kruga gdje je moguće izračunati magnetsku indukciju. Nakon toga integracijom energije rasipnog polja u namotima i prostoru oko namota, isključujući jezgru, izračunava se napon kratkog spoja transformatora. Ova metoda uzima u obzir namote različitih visina, efekt skošenja silnica polja na krajevima namota te bilo koji relativni položaj namota koji se mogu nalaziti na istom ili različitim stupovima. Predložena metoda testirana je na većem broju distribucijskih trofaznih transformatora, energetskih trofaznih transformatora i specijalnih jednofaznih transformatora. Izvorni znanstveni doprinosi ovoga rada su sljedeći: 1) metoda za izračun rasipnog polja i napona kratkog spoja transformatora primjenom konformnih preslikavanja u ravninama uzdužnog i poprečnog presjeka jezgre i namota transformatora, 2) numerički postupak za izračun energije rasipnog polja transformatora u trodimenzionalnom prostoru ekstrapolacijom dvodimenzionalnih rješenja polja u uzdužnom i poprečnom presjeku dobivenih primjenom konformnih preslikavanja i 3) algoritam za izračun raspodjele struja kroz paralelno spojene svitke visokonaponskog namota transformatora s asimetričnim rasporedom kratkospojenih niskonaponskih namota u prozoru transformatora te asimetričnom raspodjelom magnetskog polja u pokusima kratkog spoja.

Abstract (english)

This thesis describes a method for calculating the short-circuit voltage of a transformer using conformal mappings. The space inside the core window and the space outside the core in longitudinal and transverse cross-sections are mapped to a unit disk where magnetic flux density is calculated. The short-circuit voltage is calculated by the integration of the energy of the leakage field in the windings and the space around the windings, excluding the core. This method takes into account windings of different heights, the fringing effect at the ends of the windings and any relative position of windings located on the same or different limbs. The method has been tested on three-phase distribution transformers, power transformers and special single-phase transformers. The original scientific contributions of this thesis are the following: 1) method for calculation of transformer leakage field and short-circuit voltage using conformal mappings in longitudinal and transverse cross-sections of core and transformer windings, 2) numerical procedure for calculating the energy of the transformer leakage field in three-dimensional space by extrapolation of two-dimensional field solutions in longitudinal and transverse cross-sections obtained by using conformal mappings and 3) an algorithm for calculating the current distribution through parallel-connected sections of a transformer high-voltage winding with an asymmetric arrangement of short-circuited low-voltage windings in a transformer window and an asymmetric magnetic field distribution in short-circuit tests.

• Keywords: transformator; napon kratkog spoja; raspodjela struja kroz paralelno spojene svitke; konformno preslikavanje; Schwarz-Christoelova transformacija
• Keywords (english): transformer; short-circuit voltage; current distribution through parallel-connected winding sections; conformal mapping; Schwarz-Christoel transformation
• Language: croatian
• URN:NBN: urn:nbn:hr:168:903743
• Study programme: Title: Doctoral study programme "Electrical Engineering and Computing"; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, po-dručje tehničkih znanosti (doktor/doktorica znanosti, po-dručje tehničkih znanosti)
• Catalog URL: https://lib.fer.hr:8443/cgi-bin/koha/catalogue/detail.pl?biblionumber=52608
• Type of resource: Text
• Extent: xiv, 95 str.
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-03-31 07:09:22