Smanjenje broja ispada nadzemnih visokonaponskih vodova uzrokovanih atmosferskim pražnjenjima primjenom odvodnika prenapona.

doctoral thesis

• Title (english): Reducing number of high voltage overhead line outages caused by lightning applying line surge arresters.
• Author: Silvia Piliškić; MBZ: 30354239595
• Mentor: Ivo Uglešić (mentor)
• Committee member: Ivo Uglešić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; (Department of Energy and Power Systems); Zagreb
• Defense date and country: 2020, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering; Power Engineering
• Universal decimal classification (UDC): 621.3 - Electrical engineering

Abstract

Atmosferska pražnjenja jedan su od najčešćih uzroka ispada nadzemnih visokonaponskih vodova iz pogona. Metoda za smanjenje broja ispada nadzemnih visokonaponskih vodova uzrokovanih atmosferskim prenaponima primjenom odvodnika prenapona na nadzemnom vodu, predložena u ovom radu, koristi podatke sustava za lociranje atmosferskih pražnjenja. Metoda obuhvaća određivanje rasporeda odvodnika prenapona na stupovima prema relativnoj ugroženosti stupova nadzemnog voda te broja odvodnika na pojedinom stupu prema vjerojatnosti pojave povratnog preskoka ovisno o kombinaciji vrijednosti impedancije uzemljenja stupa i amplitude struje atmosferskog pražnjenja. Razvijen je frekvencijski ovisni model uzemljivača stupa modeliran kao RLC strujni krug uz poznate izraze za parametre R, L i C za zadanu geometriju uzemljivača stupa i za frekvencijski ovisne parametre specifičnog otpora i permitivnosti zemlje. Vrijednosti amplitude i kuta impulsne impedancije uzemljivača izmjerene impulsnim strujama odgovaraju vrijednostima izračunatim korištenjem frekvencijski ovisnog modela impedancije uzemljivača. Na primjeru 110 kV stupa dalekovoda pokazano je da se za tla s visokim specifičnim otporom tla impedancija stupa smanjuje s porastom frekvencije što utječe na smanjenje vjerojatnosti pojave povratnog preskoka kod atmosferskih pražnjenja. U radu je ostvaren znanstveni doprinos: predložena je metoda za odabir i određivanje razmještaja odvodnika prenapona na visokonaponskim nadzemnim vodovima te je razvijen frekvencijski ovisni model impedancije uzemljivača stupova.

Abstract (english)

Lightning is one of the most common cause of the overhead lines’ outages. A method for reducing the number of high voltage overhead line outages caused by lightning applying line surge arresters, which is proposed in this PhD thesis, uses the lightning location system data. The method encompasses the determination of the line surge arresters distribution on the towers along the overhead line according to the relative severity condition of the lightning performance of each tower in relation to the others. The probability of the backflashover occurrence depending on the tower grounding impedance and lightning current amplitude is taken into account. The frequency-dependent model of the tower grounding is developed and modelled as the RLC electrical circuit with the given expressions for RLC for the particular tower grounding geometry and frequency-dependent soil resistivity and permittivity. The frequency-dependent grounding impedance behaviour calculated using the RLC electrical circuit corresponds well with the experimental measurements, in terms of amplitude and phase angle. The simulations of the 110 kV overhead line tower stroke by the lightning have shown that the tower grounding impedance decreases with high frequencies and that the probability of the backflashover on the insulator string is lower when taking into account the frequency dependence of the tower grounding impedance for configurations with high soil resistivity. The scientific contribution in PhD thesis is as follows: the method for selection and distribution of the line surge arresters has been proposed and the model of the frequency-dependent model of the tower grounding impedance has been developed.

• Keywords: odvodnik prenapona; nadzemni visokonaponski vod; sustav za lociranje atmosferskih pražnjenja; atmosferski prenaponi; povratni preskok; proračun elektromagnetskih prijelaznih pojava; frekvencijska ovisnost; impedancija uzemljivača stupa
• Keywords (english): surge arrester; high voltage overhead line; lightning location system; lightning overvoltages; backflashover; electromagnetic transients simulations; frequency dependence; tower grounding impedance
• Language: croatian
• URN:NBN: urn:nbn:hr:168:824444
• Promotion: 2020
• 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=51891&searchid=scs_1600432691079
• Type of resource: Text
• Extent: 185 str.
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-09-18 12:40:42