• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • Tagged with
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Proračuni tokova snaga neuravnoteženih distributivnih mreža / Load Flow calculations for unbalanced distribution networks

Vidović Predrag 12 February 2015 (has links)
<p>U disertaciji je predstavljen postupak GSSKN (generalizovani postupak sumiranja<br />struja i korekcija napona) integrisan u DMS. Integracija postupka GSSKN u DMS se<br />sastoji od sledećeg: 1) postupak GSSKN se naslanja na jedinstvenu bazu podataka DMS i<br />2) rezultati dobijeni proračunom tokova snaga korišćenjem postupka GSSKN koriste<br />se u velikom broju ostalih funkcija DMS. Standardni postupak BFS (čišćenje<br />unaprjed/unazad), koji je razvijen za proračun tokva snaga uravnoteženih<br />distributivnih mreža u simetričnim režimima, u ovoj disertaciji je generalizovan na<br />uravnotežene mreže u nesimetričnim režimima, neuravnotežene distributivne mreže<br />(u nesimetričnim režimima), sa obuhvaćenim miksovanim mrežama, a da su pri tome u<br />potpunosti zapaženi robustnost, efikasnost i brzina u odnosu na ostale postupke.<br />Odnosno, u ovoj disertaciji je predložen GSSKN za proračun bilo kako složenih<br />slaboupetljanih distributivnih mreža s distributivnim generatorima, koji ima sve<br />osobine i prednosti u odnosu na ostale postupke, kao što su ih imali standardni<br />postupci BFS za proračun tokova snaga uravnoteženih slaboupetljanih<br />distributivnih mreža sa distributivnim generatorima u simetričnim režimima.<br />Dakle, osnovni cilj ove disertacije glasi: pokazati da standardne postupke BFS ne<br />samo da ne treba napuštati prilikom proračuna tokova snaga neuravnoteženih<br />slaboupetljanih aktivnih mreža (uključene miksovane), već da je to napuštanje<br />kontraproduktivno, bar sa aspekta postupaka koji su do sada objavljeni u literaturi.</p> / <p>The dissertation presents GBFS (General Backward/Forward Sweeping) procedure<br />which is integrated in DMS. The integration of the GBFS procedure in DMS<br />consists of the following: 1) the GBFS procedure is based on the unique DMS<br />database and 2) the results obtained from load flow calculation by application of<br />GBFS procedure are used in many other DMS applications. The standard BFS<br />procedure (Backward/Forward Sweeping), developed for the load flow calculation<br />of balanced distribution networks in symmetrical states, in this dissertation is<br />generalized to balanced networks in asymmetrical states, unbalanced distribution<br />networks (in asymmetrical states), including mixed networks. In addition, the<br />robustness, efficiency and speed comparing to other procedures, have been saved.<br />In other words, this dissertation proposes the GBFS procedure for calculation of<br />any composite weakly meshed distribution networks with distribution generators. It<br />has all the properties and advantages as compared to other procedures, like<br />standard BFS procedures applied for load flow calculation of balanced weakly<br />meshed distribution networks with distribution generators in symmetrical states.<br />Therefore, the basic objective of this dissertation is as follows: to show that the<br />standard BFS procedures should not be abandoned when performing the load flow<br />calculation of unbalanced weakly meshed active networks (mixed included), and<br />that, on the contrary, abandoning them would be counterproductive, at least from<br />the aspect of procedures published so far.</p>
2

Novi način procene saobraćajnih svojstava mešovite komunikacione mreže merenjem vremena odziva pozvane strane / New evaluation method of mixed communication network traffic properties by measuring of post selection delay

Matić Vladimir 04 February 2016 (has links)
<p>Osnovna svojstva telefonske mreţe, koja opisuju njen kvalitet, su kvalitet prenetog govornog signala i kvalitet u uspostavljanju telefonske veze. Na kvalitet uspostavljanja veze utiĉu mogućnost i brzina uspostavljanja veze. Brzina uspostavljanja veze se izraţava vremenima za koje se obave odreĊene aktivnosti u pojedinim fazama uspo-stavljanja veze. Trajanje ovih faza je propisano normama, koje su odreĊene meĊunarodnim propisima i date su u publikovanim preporukama. Osnovni ĉinilac brzine uspo-stavljanja veze je vreme odziva pozvane strane. Ovaj parametar se defini&scaron;e kao vremenski interval od slanja poslednjeg adresnog parametra traţenog korisnika od strane pozivajućeg korisnika, do poĉetka odgovora mreţe. U disertaciji je izvr&scaron;ena analiza vremena odziva pozvane strane u telefonskim mreţama i njegovih svojstava. Usled razlika u preno&scaron;enju adresnih informacija u klasiĉnim i savremenim paketskim mreţama, uslovi koji se odnose na vreme odgovora pozvane strane nisu isti. Ovaj zakljuĉak je formulisan u predlogu za izmenu postojećih normi koje se odnose na savremene mreţe. U nastavku je opisana mogućnost kori&scaron;ćenja vremena odziva pozvane strane u me&scaron;ovitoj mreţi kao &scaron;to je elektroprivredna telefonska mreţa, u cilju dono&scaron;enja zakljuĉka o radu mreţe. U takvoj me&scaron;ovitoj mreţi, razliĉite signalizacije i razliĉito trajanje vremena odziva pozvane strane mogu se iskoristiti za nadgledanje ispravnosti pojedinih delova mreţe odnosno detekciju neispravnih veza u njoj. Koristeći ovu osobinu, predloţen je detektor predalarmnog stanja tj. neispravnih veza u me&scaron;ovitoj telefonskoj mreţi Elektroprivrede Srbije.</p> / <p>Main features of telephone network which describe its service quality are the quality of speech signal and the quality of connection setup. The quality of connection setup is affected by the ability and the speed of connection setup. The speed of connection setup is expressed by the time needed for executing of some connection setup phases. Duration of these phases is prescribed by recommended target values, determined in international recommendations. The key indicator of connection set-up speed is post selection delay. This parameter is defined as the time interval from the moment when the complete address information about the called subscriber is sent from the calling subscriber to the network, till the moment when the answer is received from the network. The analysis of post selection delay in telephone networks and its characteristics is performed in the dissertation. Due to differences in transmission of adress information in classic and modern telephone networks, conditions dealing with the post selection delay are not same. This conclusion is formulated in the proposition for changing existing target values related to modern packet networks. In addition, the possibility of using post selection delay in mixed network, such as the telephone network of electric power utility, for monitoring the network operation is described. In such mixed network, different signaling systems i.e. different durations of post selection delay can be used for checking of proper operation of the network parts and detection of faulty connections. Applying this feature, the pre-alarm state detector is proposed.</p>
3

Proračun kompleksnih kratkih spojeva neuravnoteženih distributivnih mreža sa distribuiranim energetskim resursima / Complex Short-Circuit Calculation in Unbalanced Distribution Networks with Distributed Energy Resources

Strezoski Luka 06 October 2017 (has links)
<p>U disertaciji je predložen metod za proračun kompleksnih kratkih spojeva u aktivnim, neuravnoteženim distributivnim mrežama velikih dimenzija. Predloženim metodom je moguće proračunavati kompleksne kratke spojeve sa proizvoljno izabranim brojem čvorova i brojem faza zahvaćenih kratkim spojem, bez prethodnog komplikovanog izvođenja uslova kratkog spoja. Različiti kratki spojevi se definišu jednostavnom inspekcijom. Pored toga, svi elementi distributivne mreže su modelovani dovoljno preciznim modelima, uključujući i savremene distribuirane energetske izvore. Posebna pažnja je posvećena ovim elementima i izvođenju njihovoh modela pogodnim za proračune kratkih spojeva mreža velikih dimenzija, s obzirom da ti modeli do sada nisu bili razvijeni, a broj ovih uređaja u distributivnim mrežama je sve veći. Predloženim metodom je moguće proračunavati neuravnotežene sisteme u nesimetričnim režimima pre kratkog spoja, a proračun se vrši u domenu simetričnih komponenti. Ova činjenica čini predloženi metod izuzetno brzim i pogodnim za &ldquo;on-line mode&rdquo; distributivnog menadžment sistema. Numerički rezultati na nekoliko reprezentativnih mreža jasno prikazuju prednost predloženog metoda u odnosu na postojeće metode za proračune kratkih spojeva distributtivnih mreža.</p> / <p>In this dissertation a calculation method for quantifying the impact of complex short-circuits on active unbalanced distribution systems is proposed. Unlike previous distribution system short-circuit calculations, the proposed method is capable of solving complex short-circuits with an arbitrary number of faulted busses and phases, without predefining the boundary (fault) conditions. Different short-circuits are defined by simple inspection of these faults. Moreover, all distribution system elements are appropriately modeled and integrated in the proposed method, including electronically coupled distributed energy resources (DERs). The development of new models for these DERs, suitable for on-line calculations of large-scale systems, is specially stressed as these models have not been developed yet. Finally, the proposed calculation procedure is capable of solving unbalanced systems, including mutually coupled sections, in unsymmetrical pre-fault states, and it is performed in the sequence domain. This makes the proposed method particularly fast and suitable for online distribution system analysis. The computation results show the advantages of the proposed method relative to previous short-circuit calculation methods, regarding both the required calculation time and the accuracy.</p>

Page generated in 0.0352 seconds