In this paper is present information about dry power transformers mechanical design, common electrical characteristics, and electrical characteristics. There compare oil transformers and dry power transformers. There are given conclusions about possible in practice use dry transformers and some to offer a suggestion how to pick and choose transformers.

Summary Efficiency of the model reference based adaptive control systems is investigated and discussed in this master degree work. The main goal of this work was to evaluate and compare the performance characteristics of two widely used in mechatronics adaptive control approach – adaptive control approach based on controller parameters automatic adjustment (parameter adaptive approach) and adaptive control approach based on compensating control signal generation (signal adaptive control). Investigations were carried out on the model of the second order electromechanical velocity control system, realized with help of matlab/simulink software. Transmittance of the reference model is coincident with transmittance of conventional hierarchically arranged velocity control system, adjusted in respect of quantitative optimum conditions. The rapidity of adaptation process in the case of velocity controller detune or control object parameters change, the limits and velocity of system parameters drift and influence of external load on adaptation process were investigated for both – parameter adaptive and signal adaptive control systems cases. For obtaining of continue adaptation process, the harmonious reference and loading signals were applied on the system. The system parameters change was also modeled in harmonious mode. The modeling results allow comparing the performance characteristics of these both adaptive control methods. It was demonstrated in this work that signal... [to full text]

The theme of the filter of compensating devices current harmonics analyzed at present on work is actual, because concrete requirements on quality of electric energy are established. One of such requirements – size of harmonics in a feeding electric network. In industrial electric networks to which converters are connected, high harmonics on size reach 20-25 %. Special devices for eliminating harmonics are used. Condensers which are used for indemnification of reactive electric energy, do not extinguish them, therefore are projected the filter – compensatory installations, using capacity of the battery of condensers as base of the power filter. Bases of designing of the filter – compensatory devices of the parameters of semi-conductor converters of the electric power intended for normalization with a power line are considered. The purpose work of the master – the analysis of a factory electric network on the maximum harmonics and to design the filter for eliminating harmonics. The electric network has been checked up by device PQ ANALYSER. Such harmonics 3, 5, 7, 9, 11, 13 are found. The greatest on a current is third harmonic. Condensers of reactive capacity connected, network does not act on a harmonic. Compensatory installation which is made of separate filters of clearing of harmonics is designed, will strongly reduce the specified harmonics in a factory network.

Tyrime sulygintos senos kartos sniego valymo sistemos su nauja skaitmeninio valdymo šildymo sistema. Atsižvelgus į gautus rezultatus, pateiktiami pasiūlymai sniego valymo sistemoms efektyvumo didinimui. Tyrimas skirtas sistemų optimizavimui ir elektros energijos vartojimo mažinimui. / Point heating systems, used by SC „Lietuvos gelezinkeliai“, have to warrant safe and reliable train traffic. It is designed to melt ice which is between point’s spike and frame rail and accomplish heating elements’ and other system parts monitoring and control according the stated parameters. At present the snow blowing system use a lot of electrical energy, the research is dedicated to optimize the systems and to reeducated use of electrical energy.

Recently is topicality making wherewith more electrical energy from “clean” stockholding. Detractive hothouse gas exhaustion to the atmosphere. One “clean” energy is – wind power. Wind plans working in the commensurable electrical energy supply system, must “nuisance��. For this purpose essential wind electricity work forecast and respectively react to the situation. Wind power – station made electrical energy forecasting analysis I done sustaining by California experience. Forecasting is executable by wind forecast ground. Wind forecasts possible get from meteorological dimensional station or other institutions which doing wind range. Wind power – stations work essential to forecast at one hour 48 hours to the future. Such period is needful to other power – stations reaction. Wind power – stations worst worth to be built in the seaside zone or in the local pelagic there are not high flora or buildings. Wind power – stations can be built and in the others regions, but then increase the period of dividend.

Aim of the work 1. To analyze the methods used for the quality and resource assessment of complex insulation; 2. To develop the models for the assessment and analysis of polarization features, dielectric parameters and moisture content in oil- paper insulation; 3. To develop the method for the assessment of moisture quantity by measuring the polarization characteristics; 4. To analyze the impact of water quantity on dielectric parameters of transformer insulation; 5. To classify the quality criteria of oil-paper insulation; 6. To identify the tendencies in variation of insulation’s dielectric parameters and moisture quantity; 7. To implement the developed models and methods in the electricity industry of Lithuania for the assessment of the transformers’ insulation quality and resource.

Baigiamajame magistro darbe buvo išanalizuota didelių įstiklintų atitvarų plotų įtaka šildymo ir vėsinimo energijos sąnaudoms. Atlikta stiklo paketų, jų terminių savybių bei pasyvių energijos taupymo priemonių taikymo apžvalga. Konkretiems objektams pasirinkti penki energijos poreikių analizės variantai. Nustatyta, kaip energijos poreikius įtakoja didžiausio įstiklinto pastato fasado orientacija pasaulio šalių atžvilgiu, skirtingos stiklo paketų optinės ir šiluminės savybės bei pasyvių energiją taupančių priemonių naudojimas. Išnagrinėta apie septyniasdešimt skaičiavimo variantų. Palyginti skirtingų vėsinimo poreikių skaičiavimo metodikų rezultatai. Atlikta 2009 – 2010 m. šildymo sezono vidutinių išorės oro temperatūrų analizė. Natūrinėmis sąlygomis nustatytas patalpų oro temperatūros ir santykinio drėgnumo kitimas ir palyginta su reglamentuojamomis vertėmis. Nagrinėjamajame objekte atlikta skaičiuojamųjų ir faktinių šilumos suvartojimų, perskaičiuotų į norminius dydžius, palyginamoji analizė. / The Master's degree paper analyses the influence of large glazed areas of heating and cooling energy costs. Carried out the review of glazing, their thermal properties and the passive energy saving measures. The analysis of five options for energy needs of certain objects has been done. Established the affect to energy needs of the largest glazed façade orientation of the world's countries, different glazing optical and thermal properties and passive energy-saving tools. Examined about seventy calculation options. The results of different methods of calculating the cooling needs have been compared. Carried out the average outside air temperature analysis in 2009 - 2010 heating season. At subsistence conditions the indoor air temperature and relative humidity has been identified, and compared with the governing values. The comparative analysis in considered object of estimated and actual consumption of heat, expressed in the normative values, has been done.

Disertacijoje, taikant dinaminį pastatų energijos poreikių modeliavimą, nagrinėjamos viešosios paskirties pastatų energinio efektyvumo problemos. Pagrin-dinis tyrimo objektas yra viešosios paskirties pastato fasado įstiklinimo įtaka energijos poreikiams. Greta savo pagrindinės funkcijos – pakankamo natūralaus apšvietimo užtikrinimo, fasado įstiklinimas privalo būti energiškai efektyvus. Tai prieštaringi reikalavimai. Pagrindinis disertacijos tikslas – įvertinant natūralaus apšvietimo poreikį, kompleksiškai išanalizuoti viešosios paskirties pastato įstiklinimo charakteristi-kų įtaką pastato mikroklimato ir apšvietimo sistemų energijos poreikiams bei nustatyti, kokioms pastato įstiklinimo charakteristikoms esant, Lietuvoje bei panašaus klimato šalyse pastato energijos poreikius galima būtų sumažinti iki mažai energijos vartojančio pastato lygio. Darbe sprendžiami du pagrindiniai uždaviniai: pirmasis – atliekama įstiklinimo įtakos kondicionuojamo pastato energijos poreikiams analizė; antrasis – nustatomos efektyvios energiškai efektyvaus pastato įstiklinimo charakteristikos. Disertaciją sudaro įvadas, keturi skyriai, rezultatų apibendrinimas, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašai. Įvadiniame skyriuje aptariama tiriamoji problema, darbo aktualumas, aprašomas tyrimų objektas, formuluojamas darbo tikslas bei uždaviniai, aprašoma tyrimų metodika, darbo mokslinis naujumas, darbo rezultatų praktinė reikšmė, ginamieji teiginiai, pristatomos... [toliau žr. visą tekstą] / Applying building energy simulations, the dissertation investigates the issu-es of energy efficiency of public buildings. The main object of research – influ-ence of the glazing of the public building on its energy demand. Next to its main function to ensure daylighting, glazing must to be energy efficient. So these requirements conflict. The aim of this dissertation is to perform the complex analysis of the influ-ence of glazing characteristics on the building‘s microclimate and lighting sys-tems energy demand, taking into account DL demand. Also define, what glazing characteristics in Lithuanian and similar climate countries, are able to decrease buildings energy demand to the level of the low energy building. The paper ap-proaches two major tasks. Task 1 is performance of the detailed analysis of inf-luence of glazing on energy demand of the public building. Task 2 is determina-tion of the efficient glazing characteristics of the energy efficient building. The dissertation consists of Introduction, 4 chapters, Conclusions, Referen-ces and list of published works of the author on the topic of dissertation. The introduction reveals the investigated problem, importance of the thesis and the object of research and describes the purpose and tasks of the paper, re-search methodology, scientific novelty, the practical significance of results examined in the paper and defended statements. The introduction ends in presen-ting the author’s publications on the subject of the... [to full text]

Applying building energy simulations, the dissertation investigates the issu-es of energy efficiency of public buildings. The main object of research – influence of the glazing of the public building on its energy demand. Next to its main function to ensure daylighting, glazing must to be energy efficient. So these requirements conflict. The aim of this dissertation is to perform the complex analysis of the influence of glazing characteristics on the building‘s microclimate and lighting systems energy demand, taking into account DL demand. Also define, what glazing characteristics in Lithuanian and similar climate countries, are able to decrease buildings energy demand to the level of the low energy building. The paper approaches two major tasks. Task 1 is performance of the detailed analysis of influence of glazing on energy demand of the public building. Task 2 is determination of the efficient glazing characteristics of the energy efficient building. The dissertation consists of Introduction, 4 chapters, Conclusions, references and list of published works of the author on the topic of dissertation. The introduction reveals the investigated problem, importance of the thesis and the object of research and describes the purpose and tasks of the paper, research methodology, scientific novelty, the practical significance of results examined in the paper and defended statements. The introduction ends in presenting the author’s publications on the subject of the defended... [to full text] / Disertacijoje, taikant dinaminį pastatų energijos poreikių modeliavimą, nag-rinėjamos viešosios paskirties pastatų energinio efektyvumo problemos. Pagrin-dinis tyrimo objektas yra viešosios paskirties pastato fasado įstiklinimo įtaka energijos poreikiams. Greta savo pagrindinės funkcijos – pakankamo natūralaus apšvietimo užtikrinimo, fasado įstiklinimas privalo būti energiškai efektyvus. Tai prieštaringi reikalavimai. Pagrindinis disertacijos tikslas – įvertinant natūralaus apšvietimo poreikį, kompleksiškai išanalizuoti viešosios paskirties pastato įstiklinimo charakteristi-kų įtaką pastato mikroklimato ir apšvietimo sistemų energijos poreikiams bei nustatyti, kokioms pastato įstiklinimo charakteristikoms esant, Lietuvoje bei pa-našaus klimato šalyse pastato energijos poreikius galima būtų sumažinti iki ma-žai energijos vartojančio pastato lygio. Darbe sprendžiami du pagrindiniai užda-viniai: pirmasis – atliekama įstiklinimo įtakos kondicionuojamo pastato energijos poreikiams analizė; antrasis – nustatomos efektyvios energiškai efek-tyvaus pastato įstiklinimo charakteristikos. Disertaciją sudaro įvadas, keturi skyriai, rezultatų apibendrinimas, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašai. Įvadiniame skyriuje aptariama tiriamoji problema, darbo aktualumas, apra-šomas tyrimų objektas, formuluojamas darbo tikslas bei uždaviniai, aprašoma tyrimų metodika, darbo mokslinis naujumas, darbo rezultatų praktinė reikšmė, ginamieji teiginiai, pristatomos... [toliau žr. visą tekstą]

Darbo tikslas: Parengti lauko baseino vandens šildymo sistemą naudojant saulės kolektorius, siekiant prailginti jo naudojimo laiką. Nagrinėjama tema yra aktuali, kadangi bet koks saulės energijos panaudojimas žmonių tikslams energiją paverčiant šiluma yra aktyviai skatinamas, nes ši energija yra atsinaujinanti, nieko nekainuoja ir neteršia aplinkos, o panaudojimo galimybės - didelės. Atlikti įvairūs tyrimai ir skaičiavimai leidžia teigti, jog baseino panaudojimo negalima prailginti naudojant savos gamybos saulės kolektorių. Vandens temperatūrų pokyčiai esant skirtingiems gyliams yra nežymūs, kai apšvieta yra pakankama veikti saulės kolektoriui, o apšvietai esant mažai, skirtumai tarp skirtingų sluoksnių siekia net 3,7 oC, o tai yra pakankamai daug, kai baseino gylis yra 60 cm. Atlikus temperatūrų ir apšvietos tyrimus ir išanalizavus rezultatus matyti, jog daugeliu atvejų vandens temperaūros pokyčiai maketiniame baseine atitinka dienos apšvietos pokyčius. Šių tyrimų rezultatus galima pritaikyti, siekiant apskaičiuoti, kokių išmatavimų savadarbio kolektoriaus reikės, norint pašildyti pasirinktą lauko baseino vandenį. / Work purpuose: to prepare the open air swimming pool heating system by using sun collectors, to extend it’s working period. The relevance of investigating theme is really big, because of any sun energy using for people purpouse transferring sun energy into heat is active promoting, because this energy is renewable, costs nothing and it’s better for the environment and the usabilitys are big. Studies let’s state, that we can’t extend the use of open air swimming pool by using home made sun collector. The changes of water temperature, when the depth is different are not big when the lighting is enough to work sun collector, and when the lighting is small, the differences between water depth reaches even 3,7oC and it’s really big, when the depth of swimming pool is just 60 cm. When all the researches are done and results are analyzed, we see, that in many cases the temperature changes of pool water corresponds lighting changes. These research results may be adapted by calculating parameters of collector, by which we want to heat the open air swimming pool.