Science and Technology article citation info:
IntroductionLarge power transformers are the most critical component in electric power systems, as they are essential in maintaining a reliable supply of electric energy. There are many factors which cause a transformer malfunction, but those, which can potentially lead to catastrophic failure are winding damages (due to short-circuit, lightning, and other over-voltages) and insulation system failure (moisture, thermal aging, partial discharges). The damage from a catastrophic transformer failure may run into tens of millions of dollars [16]. To avoid such a scenario, power utilities are moving towards continuous transformer condition monitoring, based on dissolved gas analysis and acoustic emission (AE) or electromagnetic (HF/VHF/UHF) partial discharge detection.According to the newest research results and analyses presented by the experts of the CIGRE Working Group A2.37, in the technical brochure 642: Transformer Reliability Survey, the main reason of breakdowns of high voltage power transformers is damage to the windings and the main insulation system [3]. Mechanical defects in the form of winding deformations (axial displacements and radial deformations) and deterioration of insulation properties associated with thermal aging processes [6], can lead to the initiation of the partial discharge (PD) phenomena occurrence.In recent years, in the electric power industry and research centres, a trend consisting in developing and implementing advanced
Ocena możliwości zastosowania matrycy anten UHF do lokalizacji wyładowań niezupełnych Streszczenie. W artykule poruszona została problematyka lokalizacji źródeł wyładowań niezupełnych. Dzięki wykorzystaniu matrycy anten UHF w połączeniu z algorytmami kształtowania wiązki możliwe jest dokonanie estymacji kierunku nadejścia sygnału. W pracy przedstawiono wyniki badań, w których do rejestracji sygnału wykorzystano liniową matrycę anten monopolowych. Generowany sztucznie sygnał posiadał częstotliwość zbliżoną do rzeczywistej częstotliwości sygnałów emitowanych przez różnego rodzaju wyładowania niezupełne.
Electric vehicles are increasingly present on the roads of the whole world. They have the opinion of ecological vehicles, not polluting the environment. Society is more and more often persuaded to buy electric cars as an environmentally friendly solution but is this for sure? Electric cars need quite a lot of electricity accumulated in batteries to drive on a long range. During the charging process, this energy is obtained from the electricity network, to where it is supplied by power plant. Electricity production from renewable sources is a privilege for the rare. However, electric cars are charged from the electricity grid, which in large part energy comes from non-renewable fuels. The efficiency of energy production in power plants and the energy transmission and conversion chain causes that only part of the energy produced in this way goes to the vehicle’s wheels. Although the power plants are equipped with more and more efficient exhaust gas cleaning systems, they do not clean them up to 100%. Sulphur, nitrogen, mercury and heavy metals remain in the exhaust. The article is an attempt to answer the question whether the total emission of toxic components associated with the use of an electric vehicle is not bigger than in a traditional internal combustion engine.
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