Raspodjela udarnog napona po preloženom namotu transformatora

scientific master's theses

• Title (english): Distribution of surge wave through the transformer continuous disc winding
• Author: Branimir Ćućić
• Mentor: Zijad Haznadar (mentor)
• Committee member: Željko Štih (predsjednik povjerenstva)
• Committee member: Zijad Haznadar (član povjerenstva)
• Committee member: Zvonimir Valković (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; (Department of Electrical Engineering Fundamentals and Measurements); Zagreb
• Defense date and country: 2001-03-05, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering
• Universal decimal classification (UDC): 621.3 - Electrical engineering

Abstract

Svaki tip transformatora treba ispitati udarnim valom kako bi se dokazala njegova otpornost na atmosferski prenapon. Zato je potrebno pravilno dimenzionirati izolaciju transformatora koja će izdržati ispitni udarni val. U fazi projektiranja transformatora koristi se program EVT55 koji proračunava raspored udarnog vala po namotu transformatora.
Program se temelji na nadomjesnoj shemi namota. Pritom se namot dijeli na dijelove (elemente) i svaki od njih se nadomješta koncentriranim parametrima; vlastitim kapacitetom, radijalnim kapacitetima te induktivitetom. U shemi namota uzima se u račun još i međuinduktivitet elemenata. Otpor namota i vodljivost izolacije se zbog jednostavnosti zanemaruju. Na temelju Kirchhoffovih zakona formiraju se matrice kapaciteta, induktiviteta i vezne matrice te se rješava sustav od dvije matrične diferencijalne jednadžbe sa dvije nepoznanice (vektor struja i vektor napona). Vektor napona daje raspored napona po namotu transformatora. U ovom radu detaljno je obrađen račun parametara nadomjesne sheme i to: - radijalni kapacitet između elemenata - vlastiti kapacitet preloženog namota - rasipni induktivitet elementa prema kratko spojenom namotu i - međuinduktivitet između elemenata uz pretpostavku da se uz jezgru nalazi kratko spojeni i uzemljeni namot.
Kod postojećeg programa EVT55 za proračun raspodjele napona po namotu uočeni su brojni nedostaci. Program je ispravljen i nazvan EVT2000. Usporedba rezultata koje daju programi EVT55 i EVT2000 sa mjerenjem na suhom transformatoru TBS800 (22/6.3 kV, 800 kVA, uk=5.5%) pokazuje da se rezultati programa EVT2000 neusporedivo bolje slažu sa mjerenjem od rezultata programa EVT55. Napravljeno je novo grafičko sučelje koje omogućava puno jednostavniji unos ulaznih podataka.

Abstract (english)

Every type of transformer should be examined by surge wave in order to approve its resistance on atmosphere overvoltages. Because of that, transformer isolation must be well designed and withstand examined surge wave. While projecting the transformer, programme EVT55 is used to calculate the distribution of surge wave through the transformer winding. The programme is based on equivalent scheme of winding. The winding is divided into parts (called elements) and every element is presented by concentrated parameters; serial capacitance, radial capacitance and inductance. In equivalent scheme there are also the mutual inductances. The resistance and conductance are neglected because of simplicity. On the base of Kirchhoffov’s lows, matrixes of capacitance, inductance and coupled matrixes are formed and the system of two matrix differential equations with two unknowns (vector of currents and vector of voltages) is solved. Vector of voltages gives requested distribution of voltages through the transformer winding. In this work the calculation of following parameters of equivalent scheme is described in detail: - radial capacitance between the elements - serial capacitance of continuous-disc winding - stray inductance of element toward short circuited element, and - mutual inductance between the elements assuming that there is a short-circuited and grounded winding by the core. The existing programme EVT55 for calculation of surge wave distribution through the transformer winding has many defects. The programme is corrected and called EVT2000. The comparison of results of EVT55 and EVT2000 programmes with measurement on dry transformer TBS800 (22/6.3 kV, 800 kVA, uk=5.5%) shows that the results of programme EVT2000 are much closer to measurement. A new graphic interface has been made in order to enable simpler data input.

• Keywords: Transformator; udarni val; raspodjela; preloženi namot; element; radijalni kapacitet; vlastiti kapacitet; rasipni induktivitet
• Keywords (english): Transformer; surge wave; distribution; continuous disc winding; element; radial capacitance; serial capacitance; stray inductance
• Language: croatian
• URN:NBN: urn:nbn:hr:168:095248
• Study programme: Title: Postgraduate master programme in electrical engineering; Study programme type: university; Study level: postgraduate; Academic / professional title: Magistar znanosti elektrotehnike (Magistar znanosti elektrotehnike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2019-04-15 12:32:23