Wyniki 1-10 spośród 22 dla zapytania: authorDesc:"Miroslav GUTTEN"

Diagnostic of distribution transformers by SFRA method

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Power transformers are key equipment for transfer and distribution of the electric power. Considering the significance of the power transformers in the electric system, their price and possible damages occurred by accidents, it is necessary to pay attention to their higher prevention. To prevent failure states of transformers, we perform different types of measurements. They shall illustrate a m[...]

Thermal effects of short-circuit current on winding in transformer oil

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The paper deal with the decrease of mechanical strength of windings because of the thermal effects of short-circuit currents and submit the consideration for further workmanship of dimensioning for determination of the limited number of short-circuits of power transformers. Various authors experimentally have defined the decrease of material in dependence from the temperature and the time. Big deviations are among the feature curves and the measurement method data are often missing, especially about that, whether for the time of conductor thermal strain was taken in account the elapsed short-circuit duration time, or the real time of thermal strain with some temperature. With the view of the conservation of the most authentic shape of decrease of mechanical strength after short-circui[...]

The monitoring of oil transformer by gas and moisture sensor

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The paper deals with the physical fundamentals of the monitoring of values of high-voltage oil transformer 22/0,4 kV by oil Hydran sensor of gases and moisture and other assistant diagnostic apparatuses: optical temperature sensors and electric quantities analyser. Abstract. W artykule przedstawiono metodę monitorowania stanu oleju w transformatorze mocy 22/0.4 kV przy wykorzystaniu czujnika gazu i wilgotności. Metoda wspomagana jest innym narzędziami diagnostycznymi - optycznym czujnikiem temperatury i analizatorem wielkości elektrycznych. (Monitorowanie stanu oleju transformatorowego przy wykorzystaniu czujnika gazu i wilgotności) Keywords: Oil transformer, gas and moisture sensor, chromatography, monitoring, temperature sensor, gases. Keywords: olej transformatorowy, czujnik gazu, czujnik wilgotności. Introduction Electric and thermal stress transforms the dielectric oil into various gases. These gases indicate developing damage on the electric machine or apparatus and their early indication contributes to precocious intervention and financially demanding removal of the extensive damage. Created gas in insulating oil is dissolved in amount depending on the kind of the gas, quality of insulating oil, its viscosity, temperature and press. Fault occurring in transformer can develop either slowly or quickly based on its kind. Therefore it is suitable to watch the transformer running in real time so that we can continually know what is going on inside. , Because of the fact that transformer oil is dissolved into various gases it is most simple to observe right this medium. For this purpose Canadian company GE Energy Services based on lifetime experience constructed and developed apparatuses Hydran. Gas analysis released in the transformer oil According to [1] the effect of temperature, aerial oxygen, moisture and electric field in transformer leads in the process of perpetual stress of insulating system to the formation of gas pr[...]

Opportunities for integration of modern systems into control processes in intelligent buildings

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This paper presents different approaches to development of modern methods and control systems based on analysis and implementation of modern control methods. They utilize principles of robust control for thermal processes in intelligent buildings and method of Internal Model Control to calculate robust regulator parameters at non-parametric and parametric uncertainties in process model. The paper describes realized increase in robustness of control algorithm by means of programming module implemented into distributed control system based on LONWORKS technology. Streszczenie. W artykule przedstawiono odporne sterowanie procesami ogrzewania w inteligentnym budynku. Uwzględniono niepewności modelu. Wykorzystano technologię LANWORKS. (Możliwości integracji systemów sterowania w inteligentnym budynku) Keywords: Methods, intelligent buildings, LONWORKS, regulators, temperature. Słowa kluczowe: budynek inteligentny, sterowanie temperaturą. Introduction Complex control systems nowadays are designed for wide range of industrial applications. They are focused on effective management of composite processes, energy savings and optimization of production and technological processes. Intelligent buildings utilize synergy of software and hardware representing one of the widest area for application and integration of information systems, information technologies, communication systems, modern control systems and control algorithms. Application of automatic building control aims for creation of such conditions so that technically complicated and complex building could become "intelligent“. It means that it should be able to adapt to the change in internal and external conditions and so meet requirements of the owner, user and residents. This objective could not be fulfilled solely by application of advanced and most sophisticated automatic control. Automatic control needs to be combined with intelligent technologies and intelligent architect[...]

Analysis of humidity influence in a transformer model

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To prevent failure states of transformers, we perform different types of measurements. They shall illustrate a momentary state of the measured equipment and if necessary to draw attention in advance to changes of parameters, which have specific relationship to no-failure operation of the equipment. Water presence in oil transformer causes deterioration of its insulation and finally thermal defect of solid insulation Streszczenie. W artykule przedstawiono analizę wpływu wilgoci w transformatorach olejowych na przyspieszenie starzenia się materiałów izolacyjnych. Na podstawie analizy przewidzieć można potencjalne uszkodzenia i sposoby ich eliminacji poprzez zmianę parametrów transformatora. (Badania i analiza wpływu wilgotności na podstawie modelu transformatora) Keywords: Humidity, transformer, insulation resistance, dissipation factor Słowa kluczowe: wilgotność, transformator, rezystancja izolacji, współczynnik rozproszenia. Introduction State of new insulation in operation mostly deteriorates due to surface contamination of insulators and insulation, their moistening and ageing. If no measures are taken in time so as to avoid this degradation, the situation usually results in damage of insulator and consequently in stop of electrical device. State of insulation of important electrical devices, such as transmission transformer which bring huge economic cost due to each stop in operation, needs to be checked regularly. Water presence in oil transformer causes deterioration of its insulation and finally thermal defect of solid insulation. Dielectric warming can be so high that the temperature increase is out of control and transformer becomes dangerous for its surrounding. Analysis of humidity by measuring of insulation resistance The oldest and easiest method of inspecting the state of [...]

Analysis transformer insulation by PDC method

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Paragraph is about mathematical interpretation of transformer insulation system. Base of this system is composed by two elements oil and paper. We need to simulate this system for more precisely results from measurement. Section three describes how to calculate relaxation currents and how that currents are generated. So we are able to compare measured and computed values and deduce actual condition of this insulation system. Streszczenie. W artykule przedstawiono matematyczną interpretację izolacji papierowo-olejowej transformatora. W sekcji trzeciej opisano sposób obliczania prądu rozładowującego i sposób jego generacji co pozwala na porównanie wartości pomierzonej i obliczonej i określenie stanu izolacji. (Analiza izolacji transformatora metodą PDC). Keywords: Insulation, oil, paper, winding, transformer, polarization, depolarization, diagnostics. Słowa kluczowe: izolacja, olej, papier, uzwojenie, transformator, polaryzacja, depolaryzacja, diagnostyka Introduction The diagnostic of the transformers is important part of its operation. We need to know how system (transformer - insulation) works for running of the diagnostic system in ideal conditions. This is way to enable us to mathematic calculation for individual parameters. Mathematical calculation is relatively difficult in system like transformer. We only attend to a small part of mathematical simulation of this system for this reason. We angle for simulation of the polarization depolarization current method. In this method we analyze generation of this currents and we shows from what the currents are made. [1] Theory bases In last few years several diagnostic techniques have been developed and used to determine the power transformer insulation. That means this techniques must determine insulator composed from transformer oil and paper in main. Named techniques are DGA (Dissolved Gas Analysis), DP (degree of polymerization) and Furan analysis by HPLC (High Performance Liqu[...]

Measurement of electrical parameters of breakdown in transformer oil

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The initial state of breakdown development is explained on the basis of bubble theory. Application of HV-DC voltage to electrodes immersed in oil results to creation of small channels, in which streamers can develop. In the next phase a plasma channel between the electrodes can be formed. The electrical resistance of plasma channel changes from a few ohms to a few hundred milliohms due to Joule heating caused by high arc current which flows through the plasma. The dynamics of the arc current depends on the parameters of outer circuit and is represented by RLC circuit. Streszczenie. Początkowe stadium przebicia w oleju transformatorowym jest analizowane przy wykorzystaniu teorii bąbli. Przyłożenie dużego napięcia DC powoduje powstawanie kanałów. W następnej fazie powstaje kanał plazmowy między elektrodami. Rezystancja kanału plazmowego zmienia się od kilku omów do kilku miliomów na skutek ogrzewania łukowego. Parametry wyładowania łukowego zależą też od zewnętrznego obwodu RLC. (Badanie parametrów elektrycznych przebicia izolacji olejowej) Keywords: plasma channel, arc resistance, arc current, RLC circuit. Słowa kluczowe: kanał plazmowy, izolacja olejowa Introduction The electrical breakdown in transformer oil and characteristic properties of this process are very important for many applications. Insulating liquids such as transformer oils are critical components for high voltage and pulsed power system. It was reported in numerous publications that dielectric breakdown is based on complex interactions of hydrodynamic and electronic phenomenon [1, 2]. In present it is well known the initial stage of breakdown in transformer oil can be described using bubble mechanism. This theory assumes that a bubble of gas is formed by vaporization of liquid by local heating in the strong field region at a surface of the electrode. So the formed bubble will grow and a breakdown will take place inside the bubble. The breakdown processes are also d[...]

Diagnostics of electric equipments by means of thermovision

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This paper analyses problems of thermovision diagnostics measurement. It examines basic principles and application of non-contact temperature measurement. Knowledge of problems of measurement in the infrared radiation allows us to use the thermovision diagnostic methods more effectively and to localise the disturbance which determines the quality of electric equipments in the inside distribution of electric energy. Abstract. Przedstawiono zasady diagnostyki termowizyjnej. Znajomość problemów pomiaru promieniowania podczerwonego pozwala na stosowanie termoizji w sposób bardziej efektywny I bardziej dokładnie lokalizować wady. (Diagnostyka urządzeń elektrycznych przy wykorzystaniu termowizji) Keywords: thermovision, emissivity, radiation, temperature, diagnostics, calculation Słowa kluczowe: termowizja, promieniowanie podcvzerwone. Introduction Fundamental for a non-destructive diagnostics of electrical equipments using thermovision, is the ability to record and to work infrared radiation (heating) to the form of real thermal images of objects, and on the basis of overheating of certain surround, for a detection of a failure (defect). With non-contact measurement it is able to detect the temperature distribution on the surface of objects using sensitivity measuring of a few Kelvin (or °C) decimal. Fig.1. [1] Infrared radiation is generated as a result of physical processes that take place in the object of radiation; moving atoms, molecules, vibration in crystal lattice, and transition of electrons from one energy level to another. The basic source of infrared radiation is elevated temperature of the source of radiation. Fig.1 Thermogram of electric wiring breaker Radiation of hot sources acts like (in respect of surrounding conditions), like visible light. To display temperature fields we can use visualization techniques used in optics. The only differences are materials used for elements of visualization systems, size of values[...]

Mathematical analysis of transformer insulation state by means of composite indicator

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The paper is presenting mathematical model - composite indicator (CI), which was utilized on insulating state of distribution transformer to analyze and sensibility of individual measurements methods mutual comparison. We can uniquely determine importance of these measurements methods with this mathematical apparatus in these measurements methods in insulating state of transformers. Streszczenie. W artykule zaprezentowano matematyczny model wskaźnika syntetycznego, który został wykorzystany do oceny stanu izolacji transformatorów mocy. Opracowany model został zweryfikowany poprzez porównanie z innymi metodami. Wykazano zastosowanie statystycznych metod wieloatrybutowej analizy porównawczej dla oceny stanu izolacji transformatorów. (Matematyczny model wskaźnika do oceny stanu izolacji transformatorów mocy) Keywords: transformers, insulation, composite indicator, dendogram, cluster Słowa kluczowe: transformator, izolacja, wskaźnik syntetyczny, dendogram, cluster Introduction With regard to the development of world and national economics, also control, maintenance and their analysis by mathematic calculations becomes an important sphere. This sphere also includes power transformers, where their proper function has a positive impact on the trouble-free supply of electricity and heat for industries and households. The importance of diagnostics at the premises of strategic significance, results not only from an economic viewpoint, but also because of safety and faultless operation, i.e. reliability of technical equipment in the power industry. It is therefore necessary, in the absence of scientific and research potential in a distribution organizations (e.g. power plants, heating plants), to achieve the objectives of the proposed activities, i.e. in-depth analysis of undesirable impacts on the state of devices, design of measurements and their verification, and design of new diagnostic procedures for improving reliability of power trans[...]

Analysis of power transformers reliability with regard to the influences of short-circuit currents effects and overcurrents

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Abstract. This article deals with a description of methods of an experimental analysis (SFRA method, monitoring, thermovision) concerning the actual reliability of windings and magnetic circuit of the transformer, which is required in power transmission and power distribution companies all over the world. Streszczenie. Artykuł opisuje metodę eksperymentalnej analizy termowizyjnej niezawodności uzwojeń i obwodu magnetycznego transformatora. Analiza taka niezbędna jest do oceny jakości transformatorów rozdzielczych. (Analiza niezawodności transformatorów mocy z uwzględnieniem przetężeń i pradów zwarciowych) Keywords: Transformer, diagnostics, SFRA method, monitoring, thermovision. Słowa kluczowe: transformatory, termowizja, analiza niezawodności. Introduction Reliability of a techni[...]

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