Magistrantūros baigiamajame darbe tiriami įvairūs 0,4 ir aukštesnės įtampos elektros tinklo kokybiniai parametrai. Naudojant elektros tinklo kokybės analizatorių MI2192, išmatuoti elektriniai parametrai 0,4 linijose įvairiuose objektuose, surinkta papildomų duomenų iš elektros tinklų informacijos šaltinių , įvertinti kokybiniai elektros tinklo parametrai juose: įtampos sinusiškumas, nesimetrija ir svyravimai, mirgėjimas (flicker), pagrindiniai energetiniai parametrai, reaktyviosios galios dydis, harmonikų įtaka. Užregistruoti elektros tinklo parametrai palyginti su nustatytais standartais, siekiant patvirtinti arba paneigti prielaidas dėl elektros energijos kokybės ir jos įtakos įrenginių darbui. Pateiktos elektros tinklų kokybės parametrų pablogėjimo atsiradimo priežastys, mažinimo būdai. Pateiktos tyrimo rezultatų išvados. / Various 0,4 kV and qualitative parameters of higher electric power network voltage have been investigated in Master‘s final paper. Electrical parameters 0,4 KV in lines have been measured in various places using qualitative analyser M12192 of electric power network. Additional data from electric power network informational resourses have been gathered, evaluated qualitative parameters of electric power network: voltage irregular, dissymmetry and fluctuations, flicker, basic energetic parameters, dimension of reactive power (capacity, force), influence of harmonics. In pursuance of confirming or denying assumptions ref. quality of electric energy and it‘s influence on equipment work the registered electric power network parameters have been compared with the regulated standards . The paper presents the reasons of occured deterioration of electric power network quality parameters, types of power down and conclusions of investigation results.

No description available.

Kiekvieną dieną naudojame įvairius prietaisus ir įrankius skirtus palengvinti mūsų gyvenimą. Pramonės gamyklos įdiegia naujus įrenginius, kurie pagreitina ir atpigina gamybos kaštus. Kiekvienas netinkamai suprojektuotas įrenginys gali kelti pavojų vartotojui ar aplinkai. Elektrotechniniai įrenginiai išsiskiria specifiniais elektros saugos reikalavimais. Kadangi rinkoje gausybė prekių, kurias gali įsigyti visi rinkos dalyviai yra būtina įdiegti bendrus saugos reikalavimus. Gamintojai privalo laikytis šių reikalavimų ir prisiimti visą atsakomybę už savo gaminių padarytą žalą vartotojui. Tam, kad apsaugoti vartotojus, Europos Sąjunga įteisino specialią bendrosios rinkos sistemą. Ši sistema palaiko rinkoje saugius gaminius ir neatitinkančius saugos reikalavimų – šalina. Taip rinkoje dalyvauja tik tokie gaminiai, kurie pagaminti taip, jog nepažeidžia jokių iki šiol nustatytų saugos, sveikatos bei aplinkos apsaugos reikalavimų. Tačiau vartotojas neturėtų aklai pasitikėti šia sistema, kadangi atsiranda gamintojų, piktnaudžiaujančių šiais saugos reikalavimais. Tokie gamintojai rizikuodami pardavinėja nesaugius gaminius manydami, jog nieko blogo neatsitiks. Iš kitos pusės, kai kurie gamintojai nepakankamai išmanydami šiuos reikalavimus netyčiomis pardavinėja nesaugius produktus. Rinką prižiūrinčios institucijos gali nespėti laiku aptikti ir uždrausti gaminius. / We are using devices and tools to facilitate our lives every single day. An improperly designed device can pose a risk to consumers or the environment. There are many items in the market that can be purchased by any user, so it is necessary to implement common safety requirements. In order to protect consumers, the European Union enacted a special single market framework. This system holds safe products on the market and eliminates the ones that do not conform safety requirements.

Elektros inžinerijos bakalauro baigiamojo darbo tema yra aktuali, nes elektros tinklai sumontuoti prieš 30–40 metų jau yra pasenę ir nebeatitinka šiuolaikinių poreikių. Vis daugiau elektros vartotojų keičia dujines virykles į elektrines, įsigija naujų elektros prietaisų, elektros suvartojimas auga, todėl būtina atnaujinti elektros tinklus, siekiant užtikrinti patikimą kokybiškos elektros energijos tiekimą. Šiuo projektu Skomantų kaime numatoma esamos oro linijos L-300 iš transformatorinės KT-V-305 rekonstravimas, ją pakeičiant apskaičiuoto skerspjūvio 0,4 kV elektros kabelių linijomis su reikiamu skaičiumi 0,4 kV skirstomųjų spintų (SS), įvadinių apskaitų skirstomųjų spintų (ĮASS) ir įvadinių apskaitų spintų (ĮAS). Numatoma trumpinti esamą oro liniją L-100 iš transformatorinės KT-V-305, pastatant dvi stulpines transformatorines su 25 kVA ir 40 kVA galios transformatoriais. Planuojamas oro linijos L-100 iš transformatorinės KT-V-305 ruožų nuo atramos Nr. 100/9 iki atramos Nr. 100/25 ir nuo atramos Nr. 101/18 iki atramos Nr. 101/25 demontavimas. / His Bachelors’ degree electrical engineering thesis is relevant, because the electricity network built 30-40 years ago in Skomantai village is already old and no longer meets todays’ needs. More and more electricity consumers change gas stoves into electrical stoves, purchase new electrical devices. The usage of electricity is increasing. That’s why the renewal of electrical network is needed in order to maintain reliable supply of high quality electric power. The plan of this project in Skomantai village is the reconstruction of existing transmission line L-300 from the transformer KT-V-305 reconstructing it by changing with calculated cross-section 0,4 kV electricity cables’ lines with needed number 0,4 kV 0,4kV distribution boards (SS), electrical distribution and metering equipment boards (ĮASS) and lead-in metering boards (ĮAS). Shortening of the existing transmission lines L-100 from transformer KT-V-305 and building two pole transformers with 25 kVA and 40 kVA power transformers. Dismantling of transmission line L-100 from transformer KT-V-305 parts from pole No. 100/9 up to pole No. 100/25, and from pole No. 101/18 up to No. 101/25.

Thesis (MSc (Electrical and Electronic Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Knowledge of the magnetic fields in the domain of electrical machines is required in order to model machines accurately. It is difficult to solve these fields analytically because of the complex geometries of electrical machines and the non-linear characteristics of the materials used to build them. Thus, finite element analysis, which can be used to solve the magnetic field accurately, plays an important part in the design of electrical machines. When designing electrical machines, the task of finding an optimal design is not simple because the performance of the machine has a non-linear dependence on many variables. In these circumstances, numerical optimisation using finite element analysis is the most powerful method of finding optimal designs. In this thesis, the work of improving an existing finite element simulation package, formerly known as the Cambridge package among its users, and the use of this package in the optimisation of electrical machine designs, is presented. The work involved restructuring the original package, expanding its capabilities and coupling it to numerical optimisers. The developed finite element package has been dubbed SEMFEM: the Stellenbosch Electrical Machines Finite Element Method. The Cambridge package employed the air-gap element method, first proposed by Razek et. al. [2], to solve the magnetic field for different positions of the moving component in a time-stepped finite element simulation. Because many new machine topologies have more than one air-gap, the ability to model machines with multiple air-gaps is important. The Cambridge package was not capable of this, but during the course of this work, the ability to model machines with multiple air-gaps using the air-gap element method was implemented. Many linear electrical machines have tubular, axisymmetric topologies. The functionality to simulate these machines was newly implemented because the original program was not capable of analysing these machines. Amongst other things, this involved the derivation of the coefficients of an axisymmetric air-gap element’s stiffness matrix. This derivation, along with the original air-gap element derived by Razek et. al. [2] and the extension of the method to the Cartesian coordinate system by Wang et. al. [29, 30], completes the derivation of all two-dimensional air-gap elements. In order to speed the numerical optimisation process, which is computationally expensive, parallelisation was introduced in two areas: at the level of the finite element simulation and at the level of the optimisation program. The final product is a more powerful, more usable package, geared for the optimisation of electrical machines. / AFRIKAANSE OPSOMMING: Kennis van die magnetiese velde in die gebied van elektriese masjiene word benodig om masjiene akkuraat te modelleer. Dit is moeilik om hierdie velde analities op te los as gevolg die komplekse geometrieë van elektriese masjiene en die nie-lineêre karakteristieke van die materiale wat gebruik word om hulle te bou. Dus speel eindige element analise ’n belangrike rol in die ontwerp van elektriese masjiene omdat dit gebruik kan word om die magnetiese veld akkuraat te bepaal. Wanneer elektriese masjiene ontwerp word, is dit nie ’n eenvoudige taak om ’n optimale ontwerp te vind nie omdat die werkverrigting van die masjien nie-lineêr afhanklik is van baie veranderlikes. Onder hierdie omstandighede is numeriese optimering, tesame met eindige element analise, die kragtigste metode om optimale ontwerpe te vind. In hierdie tesis word die verbetering van ’n bestaande eindige element simulasie pakket, wat onder gebruikers van die pakket as die Cambridge pakket bekend staan, en die gebruik van hierdie pakket vir die optimering van elektriese masjiene, voorgelê. Die werk het die herstrukturering van die oorspronklike pakket, die uitbreiding van die pakket se vermoëns en die koppeling van die pakket aan numeriese optimeerders behels. Die ontwikkelde eindige element pakket word SEMFEM genoem: die Stellenbosch Elektriese Masjiene Finite Element Method. Die Cambridge pakket het van die lugspleet element metode, soos oorspronlik deur Razek et. al. [2] voorgestel, gebruik gemaak om die magnetiese veld vir verskillende posisies van die bewegende komponent in ’n tyd-stapsgewyse eindige element simulasie op te los. Omdat baie nuwe masjien topologieë meer as een lugspleet het, is die vermoë om masjiene met meer as een lugspleet te kan modelleer belangrik. Die Cambridge pakket was nie hier toe in staat nie, maar die vermoë om masjiene met meervoudige lugsplete te modelleer is gedurende hierdie werk geïmplementeer. Baie lineêre masjiene het tubulêre, assimmetriese topologieë. Die funksionaliteit om hierdie masjiene te simuleer is nuut geïmplementeer omdat die oorspronlike program nie in staat was om hierdie masjiene te analiseer nie. Dit het onder andere behels dat die koeffisiënte van ’n assimmetriese lugspleetelement se styfheidsmatriks afgelei moes word. Hierdie afleiding, tesame met die oorspronlike lugspleetelement afgelei deur Razek et. al. [2] en die uitbreiding na die Cartesiese koördinaatstelsel deur Wang et. al. [29, 30], voltooi die afleiding van alle twee-dimensionele lugspleet elemente. Om die numeriese optimeringsproses, wat tipies tydsgewys duur is, te versnel, is parallellisering op twee vlakke ingebring: op die vlak van die eindige element simulasie en op die vlak van die optimeringsprogram. Die finale produk is ’n kragtiger, meer bruikbare pakket, goed aangepas vir die optimering van elektriese masjiene.

Text in English, with English, Afrikaans and Zulu summaries / This study was conducted owing to the protracted problem and challenges that unauthorised electrical connections pose to electricity utilities. This study sought to contribute to the combating of unauthorised electrical connections in KwaZulu-Natal, South Africa, which has never before been studied in this manner. Considerable revenue is stolen from utilities because of unauthorised electrical connections, by-passing of electrical meters and tampering with electricity networks. This contributes to public safety risks, fatalities, property damage and overloading of electrical networks. This in turn causes transformer and electricity network overload and power supply failure, prolonged unplanned power cuts, loss of jobs, food security risk, serious poor economic development, damaged electrical infrastructure, loss of revenue, electricity disruptions, electric shock, and the burning of dwellings. This leads to the interruption of supply to legal and compliant customers, all with disastrous effects. It is therefore difficult to manage the supply and demand of electricity under these circumstances, more especially in this period when South Africa faces a tight electricity supply. In this dissertation, the international and national perspectives reveal the nature and extent of unauthorised electrical connections. It was explored how unauthorised electrical connections are presently being combated and what specific security measures may be implemented to enhance the combating of unauthorised electrical connections. A case study design was used to investigate in greater detail the opinions, views, perceptions and experiences of the targeted interviewees using interviewing, site observation and case docket analysis. This design guided the use of specific sample groups, procedures and techniques used for data collection and analysis. The design and development of the different data collection instruments and the piloting of the instruments were implemented to ensure validity, reliability, accuracy and trustworthiness of the collected information. The study produced findings to assist electricity utilities to better manage this phenomenon. Recommendations were formulated to assist stakeholders to improve their roles in the combating of unauthorised electrical connections. / Hierdie studie is uitgevoer na aanleiding van die uitgerekte probleem en uitdagings van onwettige elektrisiteitsverbindings vir elektrisiteitsvoorsieners. Hierdie studie poog om by te dra om onwettige elektrisiteitsverbindings in KwaZulu-Natal, Suid-Afrika te beveg; dit is nog nooit tevore op hierdie wyse ondersoek nie. Beduidende inkomste word van diensmaatskappye gesteel as gevolg van onwettige elektrisiteitsverbindings, die wat elektriese meters omseil en met elektrisiteitsnetwerke peuter. Dit dra tot openbare veiligheidsrisiko's, fataliteite, skade aan eiendom, en oorlading van elektrisiteitsnetwerke by. Dit lei weer tot oorlading van transformators en elektrisiteitsnetwerke, gebrek aan kragvoorsiening, verlengde onbeplande kragonderbrekings, werksverlies, voedselsekuriteitrisiko, ernstige swak ekonomiese ontwikkeling, skade aan elektrisiteitinfrastruktuur, verlies aan inkomste, elektriese skok, en huise wat afbrand. Dit lei tot die onderbreking van voorsiening aan wetlike en inskiklike klante met rampspoedige gevolge. Dit is dus moeilik om voorsiening en vraag na elektrisiteit in hierdie omstandighede te bestuur, veral in hierdie tyd wat Suid-Afrika drukkende elektrisiteitvoorsiening beleef. In hierdie verhandeling onthul die internasionale en nasionale perspektiewe die aard en mate van onwettige elektrisiteitsverbindings. Dit was ondersoek hoe onwettige elektrisiteitsverbindings tans beveg word en watter spesifieke veiligheidsmaatreëls geïmplementeer kan word om die bevegting van onwettige elektrisiteitsverbindings te bevorder. Die gevallestudie-ontwerp is gebruik om die onderhoudgewers se menings, sienings, perspektiewe en ervarings in meer besonderhede te ondersoek deur onderhoude, waarnemings en saakdossierontledings te gebruik. Die ontwerp het die gebruik van spesifieke steekproefgroepe, prosedures en tegnieke wat vir dataversamelings en -ontleding gebruik is, gerig Die ontwerp en ontwikkeling van die verskillende dataversamelinginstrumente en die bestuur van die instrumente is geïmplementeer om geldigheid, betroubaarheid, akkuraatheid en geloofwaardigheid van die versamelde inligting te verseker. Die studie se bevindings help elektrisiteitsdienste om hierdie verskynsel beter te bestuur. Aanbevelings is geformuleer om belanghebbers te help om hul rolle te bevorder in die stryd om onwettige elektrisiteitsverbindings te beveg. / Ucwaningo lwenziwa ngenxa yokubona inkinga egxilile neqhubekela phambili kanye nezinselele ezibangelwa ukuzixhumela ama-connection kagesi (i-elektrisithi) maqondana nezinkampani zikagesi. Ucwaningo belufuna ukufaka esivivaneni kudaba lokuvimbela ukuzixhumela kogesi ngendlela engekho emthethweni eKwaZulu-Natali, eNingizimu Afrika, yona okungakaze kwenziwe ucwaningo ngayo ngale ndlela. Kunengeniso eliningi lemali entshontshwa ngale ndlela kwizinkampani noma izinhlangano zikagesi ngoba kunokuzixhomela ugesi okungekho emthethweni, ukungasetshenziswa kwamamitha ogesi, kanye nokuphazamisa ama-network kagesi. Lokhu kubangela izingozi nokungavikeleki kubantu bonke, ukulimala, ukulinyazwa nokonakala kwempahla noma iprophathi kanye nokuthi ama-network kagesi agxisheleke nokucindezeleka ngokweqile. Kanti futhi lokhu kubanga ukuthi ama-transformer kanye nama-network kagesi acindezeleke ngokweqile nokwenza ukuthi isaplayi kagesi ihluleke nokufeyila, lokhu okubangela ukuthi kube nama-power cuts noma ukucishwa kukagesi okungahleliwe, ukulahleka kwemisebenzi, ingozi yokuphazamiseka kokuvikeleka kokudla, ukuthi ukuthuthuka komnotho kuphazamiseke kakhulu, ukulahleka kwengeniso lemali, ukuphazamiseka kokuphakelwa kukagesi, ukulinyazwa kwabantu ngokubanjwa ugesi, kanye nokusha kwemizi eshiswa ugesi. Lokhu kuholela ekutheni kuphazamiseke isaplayi kagesi kumakhastama akhokha kahle nenza izinto ngokulandela umthetho, lokhu okubanga imiphumela yezinhlekelele ezimbi. Ngakho-ke kuba nzima ukubhekana kanye nezinto zesaplayi kanye nokudingeka kukagesi ngaphansi kwalezi simo, ikakhulukazi lapho iNingizimu Afrika ibhekene nokuncipha noma izinga eliphansi lesaplayi kagesi. Kule dissertation isimo sikazwelonke kanye nesamazwe omhlaba, siveze inhlobo kanye nezinga lokuxhunyelwa kukagesi okungekho emthethweni. Kubuye kwabheka nokuthi ukuxhunyelwa kukagesi okungekho emthethweni kubhekwana kanye nokuvinjelwa kanjani, nokuthi yiziphi izindlela eziqondene ezisetshenziswayo zokuvikeleka ezingasetshenziswa ukuthuthukisa izinqubo zokuvimbela ukuxhunyelwa kukagesi nama-connection angekho emthethweni angavinjelwa kanjani . Kusetshenziswe idizayini ye-case study ukuphenyisisa ngokujulile imininingwane, imibono, izinqubo zokubheka isimo kanye nezipiliyoni zalabo obekuqondiswe kubo ama-interview ngesikhathi kwenziwa ama-interview, ukuyobheka ngamehlo esimo ezindaweni, kanye nokuhlaziya amadokhethi amacala ngokwenzekayo. Le dizayini yiyona eholele ekusetshenzisweni kwamasampuli amaqembu athize, izinqubo noma amaprosija athize kanye namathekniki athize asetshenzisiwe ekuqoqeni kwe-data kanye nohlaziyo lwayo. Idizayini nokwenziwa kwama-instrumenti okuqoqwa kwe-data ehlukene, kanye nokwenza ama-instrumenti okulinga noma e-piloting, kusetshenzisiwe ukuqinisekisa i-validity, ukuthembeka (reliability), ukuqondana ncamashi kwama-instrumenti (accuracy) kanye nokuqiniseka okubizwa ngokuthi yi-trustworthiness yolwazi noma i-infomeshini eqoqiwe. Ucwaningo, lukhiphe imiphumela yokusiza izinkampani noma izinhlangano zikagesi ekuphatheni kangcono le nkinga noma ifenominoni (phenomenon) yenkinga. Kwenziwe izincomo zokusiza ababambe iqhaza (stakeholders) ukuthuthukisa indima yabo ekulwiseni ukuxhunyelwa kanye nama-connection kagesi angekho emthethweni. / Criminology and Security Science / M. Tech. (Security Management)

No description available.

Elektrické stroje se používají v mnoha oblastech života spo¬lečnosti a vyrábí se ve velkém množství a sortimentu. Jedním z nejvíce používaných druhů jsou elektrické stroje malého výkonu na malé a nízké napětí. V širším smyslu názvem malé elektrické stroje označujeme takové stroje, které mají výkon menší než 1 kW (1000 W). Z hlediska užití můžeme rozdělit malé elektrické stroje na stroje pro obecnou potřebu a pro automatizační zařízení. Jedním z nejvíce frekventovaných druhů malých elektrických strojů jsou elektrické stroje na malé napětí, t.zn. na jmenovité napětí do 50 V.

Studium nových materiálů potenciálně využitelných pro organickou elektroniku a fotoniku získává velmi důležitý význam z hlediska ekologie. Tato práce je zaměřena na studium vlastností biologických materiálů, které by našly uplatnění v aplikační sféře. Zájem o znalosti v oblasti základních a pokročilých vlastností organických a biologických materiálů, které mohou být potenciálně využity v oblasti organické elektroniky a fotoniky přináší nové otázky, které mohou přispět k rozvoji této oblasti. Ke studiu základních procesů souvisejících s optickými a elektrickými vlastnostmi materiálů, jako je například přenos náboje, jsme využili různé techniky a metody charakterizace. První část práce je zaměřena na souhrn vlastností anorganických a organických materiálů umožňující jejich možné využití v organické elektronice a fotonice, druhá část práce poskytuje nejnovější přehled z oblasti pokročilých biologických materiálů a jejich vlastností související se záměrem této práce. Třetí část práce pak shrnuje experimentální metody a shrnuje získané výsledky. Nakonec je diskutován vztah mezi pozorovanými jevy a strukturou studovaných materiálů na molekulární úrovni.

Thesis (M.S.)--Utah State University, 2009. / Title from title screen (viewed Jan. 12, 2010). Department: Electrical and Computer Engineering. Includes bibliographical references. Archival copy available in print.