Title Stohastički proračun strujnih harmonika u razdjelnim mrežama Title (english) Stochastic Calculation of Current Harmonics in Distribution Networks Author Lahorko Wagmann Mentor Zvonko Benčić (mentor)Committee member Vladimir Mikuličić (predsjednik povjerenstva)Committee member Zvonko Benčić (član povjerenstva)Committee member Vitomir Komen (član povjerenstva)Committee member Ante Marušić (član povjerenstva)Committee member Viktor Šunde (član povjerenstva)Granter University of Zagreb Defense date and country 2010-10-04, Croatia Scientific / art field, TECHNICAL SCIENCES Universal decimal classificationUDC ) 621.3 - Electrical engineering Abstract Uslijed sve veće uporabe nelinearnih trošila u kućanstvima dolazi do povlsenja razine naponskih harmonika u razdjelnim mrežama niskog i srednjeg napona. Pojedinačno nelinearno trošilo, zbog svoje male snage, općenito ne utječe na promjenu valnog oblika napona. Zbirni utjecaj takvih trošila međutim, može biti vrlo značajan. Najčešća nelinearna trošila u niskonaponskim mrežama su: zabavna elektronika, uredska tehnika, rasvjeta te elektromotorni pogoni s elektroničkim pretvaračima. Svrha disertacije je istražiti mogućnost pronalaženja matematičkog modela procjene razine harmonika u distribucijskim mrežama koji se može koristiti u standardnim programskim paketima za izračun harmonika kada mjerenja nisu dostupna. Stohastički proračun harmonika može se primijeniti u analizi povratnog utjecaja kod priključenja postrojenja korisnika mreže na elektroenergetski sustav. Na temelju mjerenja strujnih harmonika i opterećenja na gradskim transformatorskim stanicama 10(20)/0, 4 kV koje napajaju kućanstva u radu su istražene metode pronalaženja stohastičkog modela transformatorske stanice kao skupnog izvora strujnih harmonika. Također je istražena mogućnost procjene statističke razdiobe tjednih vrijednosti strujnih harmonika na transformatorskoj stanici Monte Carlo simulacijom, poznavajući podatke potrebne za planiranje mreže kao što su vršno opterećenje transformatorske stanice i tip potrošnje. Stohastički model transformatorske stanice u uključen je Monte Carlo proračun harmonika u srednjonaponskoj mreži. Izvorni znanstveni doprinosi rada su: metoda stohastičkog modeliranja strujnih harmonika uzrokovanih trošilima na transformatorskoj stanici postupkom rastavljanja skupa izmjerenih vrijednosti na stohastičku i determinističku komponentu, metoda prognoze prosječne dnevne krivulje strujnih harmonika na transformatorskim stanicama iz vršnog opterećenja i tipa potrošnje pomoću klaster analize i regresijske analize te algoritam Monte Carlo izravnog proračuna harmoničkih tokova snaga s uključenim stohastičkim modelom transformatorske stanice kao grupnog izvora strujnih harmonika.
Abstract (english) More intensive usage of nonlinear loads in the households leads to the growth of harmonic voltage level in the low and medium voltage networks. One non linear load, because of its small power, generally doesn’t influence the change of voltage wave shape. Summation of the influence of such loads, on the other hand, could be significant. The most frequent non linear loads in low voltage networks are: consumer electronics, office appliances and motor drives with static converter. The purpose of this dissertation is to investigate the possibility of finding the mathematical model for assessing harmonics level in the distribution networks which could be used in standard program packages for harmonic calculation when the measurements are not available. The stochastic harmonic calculation could be applied in analyzing the reverse impact of user’s plants to the electrical network. On the basis of current harmonic and load measurement at the urban transformer stations 10(20)/0,4 kV which feed households, the method of finding the stochastic model of transformer station as group source of current harmonic is investigated. Also is investigated the possibility of assessment of the statistic distribution of weekly values of current harmonics at the transformer station with Monte Carlo simulation, knowing the data needed for network planning like a maximum load and type of consume. The stochastic model of transformer station has been included in harmonic Monte Carlo calculation of distribution network. The original scientific contributions of this work are: the method of stochastic modeling of current harmonics originated by the loads fed by the transformer station through the process of disaggregation of measured values to stochastic and deterministic component, the method of prediction of the average harmonic current daily curve at the transformer station on the basis of maximum load and the type of consume with the cluster analysis and the regression analysis and the Monte Carlo algorithm of direct harmonic load flow calculation with included stochastic model of transformer station as a group source of current harmonics.
Keywords
harmonici
stohastički proračun
metoda Monte Carlo
nelinearna trošila
klaster analiza
regresijski model
Keywords (english)
harmonics
stochastic calculation
Monte Carlo method
nonlinear loads
cluster analysis
regression model
Language croatian URN:NBN urn:nbn:hr:168:278124 Project Number: 036-0362978-1574 Project Number: 036-0362978-2314 Study programme Title: Computer Science Catalog URL http://lib.fer.hr/cgi-bin/koha/opac-detail.pl?biblionumber=34278 Type of resource Text Extent 205 str. ; 30 cm File origin Born digital Access conditions Closed access Terms of use Created on 2019-03-19 09:59:14
