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Abstrakt

Extensive efforts have been made for many years by the power generating industry to replace conventional solid and liquid insulation with synthetic materials. Those measures are aimed at increasing the load capacity, improved fire safety and extending transformer life during exploitation. Modern insulating materials include aramid fibre-based paper and insulating fluids made of synthetic and natural esters. The paper presents research results of the electrostatic charging tendency (ECT) of mixtures of fresh and aged mineral oil Trafo En with synthetic ester Midel 7131 and natural ester Midel 1204. The measurements were taken in a flow-through system using the pipes made of metal, cellulose and aramid paper. The influence of the liquid flow velocity, the type of material of the measuring pipe and the mixture content on the level of the streaming electrification current generation was determined.
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Abstrakt

The increment in the number of automobiles and the densification of the city has increased noise pollution rates. In addition, the lack of regulation in Chile regarding the acoustic insulation of façades is a problem of a growing concern. The main objective of the present study was to obtain a model of the Sound Insulation of housing, façades, stratified in Santiago, Chile, based on constructive variables. It is expected to serve as a basis for one future regulation for acoustic façades of houses. In the present study, tests based on the international ISO 140-5 standard were carried out in situ. An estimation model of the Standardized Level Difference Dls,2m,nT,w + C, was obtained based on the opening/façade proportion, and the type of glass used for the windows.
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Abstrakt

The article presents the results concerning the use of clustering methods to identify signals of acoustic emission (AE) generated by partial discharge (PD) in oil-paper insulation. The conducted testing featured qualitative analysis of the following clustering methods: single linkage, complete linkage, average linkage, centroid linkage and Ward linkage. The purpose of the analysis was to search the tested series of AE signal measurements, deriving from three various PD forms, for elements of grouping (clusters), which are most similar to one another and maximally different than in other groups in terms of a specific feature or adopted criteria. Then, the conducted clustering was used as a basis for attempting to assess the effectiveness of identification of particular PD forms that modelled exemplary defects of the power transformer’s oil-paper insulation system. The relevant analyses and simulations were conducted using the Matlab estimation environment and the clustering procedures available in it. The conducted tests featured analyses of the results of the series of measurements of acoustic emissions generated by the basic PD forms, which were obtained in laboratory conditions using spark gap systems that modelled the defects of the power transformer’s oil-paper insulation.
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Abstrakt

An alternative method for analysis of acoustic emission (AE) signals generated by partial discharges (PD), based on a correlation between voltage phase run and AE pulses, so called phase resolved PD pattern (PRPD), is presented in the paper. PRPD pattern is a well-known analysis tool commonly used in such PD diagnostic methods as conventional electrical and UHF ones. Moreover, it yields various signal analysis abilities and allows a direct correlation indication between measurement results achieved using different methods. An original PRPD measurement methodology applied for AE method as well as some exemplary measurement results and further data analysis capabilities are presented in the paper. Also a comparative analysis of PRPD patterns achieved using various measurement methods and different PD source configurations have been investigated. All presented experiments were done under laboratory conditions using PD model sources immersed in the insulation oil. The main purpose of the presented research is to indicate an all-embracing analytical tool that yields an ability to direct comparison (qualitative as well as quantitative) of the AE measurement results with other commonly applied PD measurement methods. The presented results give a solid fundamental for further research work concerning a direct correlation method for AE and other described in the paper diagnostic techniques, mainly in order to continue PD phenomena analysis and assessment in real life high voltage apparatus insulation systems under normal onsite operation conditions.
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Abstrakt

The results from the experimental research are presented in the abstract. The experimental research involved utilization of the sludge from the mine water treatment plant of Coal Quarry ČSA/Czechoslovak Army/ (hereinafter “ČSA”) and Coal Quarry Jana Švermy (hereinafter “JŠ”) in the segment of thermal insulation mortars. The mine water treatment is described below including chemical and mineralogical sludge composition as the additional component of the binding material in the polyurethane thermal insulation mortars. Furthermore the composition of experimental mixtures of the thermal insulation polyurethane mortar is presented in the work and its physical-mechanical properties. The monitored elements included the strength characteristics, heat conductivity coefficient λ, and water vapour diffusion coefficient μ.
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Abstrakt

Partial discharges (PD) are influencing electrical insulating systems of high voltage electrical devices. Typically, in laboratory and diagnostics AC tests focused on measuring and analysis of PD, a pure sinusoidal voltage waveform is assumed. However, in practice the spectral content of the working voltage is rarely so ideal and additional spectral components have a significant impact on the discharge behaviour in electrical insulation systems. In this paper the influence of voltage harmonics on PD behaviour and phase-resolved PD patterns evolution is analysed. The presented experiments were conducted on a specimen representing a gaseous inclusion embedded in electrical insulation. The experimental results showed that various harmonic compositions superimposed on the fundamental sinusoidal waveform have a significant impact on PD intensity and maximum charge. In consequence, the derived patterns of PD phase, and magnitude distributions are distorted, and statistical parameters calculated on their basis are changed. In certain en- vironments, neglecting harmonic content in the testing voltage may lead to a misleading interpretation and assessment of PD severity.
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Abstrakt

Wprowadzane nowe przepisy legislacyjne, regulujące w naszym kraju obrót paliwami stałymi, zwracają uwagę na konieczność rozwijania i doskonalenia sposobów i metod zagospodarowania mułów węglowych z węgla kamiennego. Celem pracy było wykazanie, czy parametry filtracyjne (głównie współczynnik filtracji) mułów węglowych są wystarczające do budowy warstw izolujących na składowiskach na etapie ich zamykania i jakie jest zapotrzebowanie na materiał w przypadku takiego postępowania. Analizę przeprowadzono dla składowisk odpadów komunalnych na obszarze województw opolskiego, śląskiego i małopolskiego. Dla mułów węglowych z górnictwa węgla kamiennego wartości współczynnika filtracji mieszczą się w zakresie 10–8‒10–11 m/s, przy średniej wartości 3,16 × 10–9 m/s. Można wnioskować, że materiał ten spełnia zasadniczo kryteria szczelności dla przepływów poziomych i często też pionowych. Przy zagęszczaniu, wzrastającym obciążeniu czy mieszaniu z popiołami lotnymi ze spalania węgla kamiennego oraz iłami osiągany współczynnik filtracji często obniża swoje wartości. Na podstawie przeprowadzonej analizy można sądzić, że muły węglowe mogą zostać wykorzystane do budowy mineralnych barier izolujących. Na koniec roku 2016 na obszarze województw opolskiego, śląskiego i małopolskiego czynnych było 50 składowisk odpadów komunalnych. Jedynie 36 z nich uzyskało status instalacji regionalnej, blisko 1/3 obiektów znajduje się w zasięgu Głównych Zbiorników Wód Podziemnych (GZWP). Pozostałe składowiska zostaną przeznaczone do zamknięcia. Zakładając konieczność zamknięcia wszystkich czynnych obecnie składowisk odpadów komunalnych, zapotrzebowanie na muły węglowe wynosi ogółem 1 779 000 m3, co przy przyjętych założeniach daje masę 2 704 080 Mg. Całkowita ilość wytwarzania mułów węglowych jest w Polsce bardzo duża. Tylko dwie podstawowe grupy górnicze wytwarzają rocznie łącznie około 1 500 000 Mg mułów węglowych. Budowa warstw izolujących na składowiskach odpadów obojętnych, niebezpiecznych oraz innych niż niebezpieczne i obojętne jest interesującym rozwiązaniem. Takie zastosowanie jest perspektywiczne, ale nie rozwiąże całościowo problemu związanego z wytwarzaniem i zagospodarowaniem tego materiału odpadowego. Istotne jest poszukiwanie kolejnych rozwiązań.
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Abstrakt

Urethane foam mattresses are commonly used as cushioning when placing panel flooring on the floor slab of a building. Urethane foam consists of elastic fibres with pores. Both elements can affect the performance of the insulation against impact sounds. However, these effects have not yet been detailed, and they may change if the material properties or constitution of the fibres and pores in the cushioning change. In this paper, we propose an analytical model for use in evaluating the performance of insulation against floor impact sound. This model was used to examine the contribution of the pores versus the elastic fibres to wave transmissions from the flooring surface to the slab. The results reveal that the constitution of the foam (either open or closed cells of pores) and the thickness and hardness of the cushion layer strongly affect the sound insulation performance of the floor.
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