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This paper describes partial discharge signal analysis and transform methods used for this analysis. It focuses especially on Fourier and Wavelet transform and points out the suitability, advantages and differences between these transforms.
The paper offers an analysis of the distribution of the values of SAIDI and SAIFI indices in nineteen Polish companies dealing with electricity distribution. The data presented concern the assessment of the reliability of electricity supply to over 10.5 million consumers. The paper analyses the influence of the number of remotely controlled switches installed within a MV network on the values of SAIDI...
Composite insulation systems are inseparable part of most electrical installations. Strongly inhomogeneous structure of these systems is the main problem which may lead to defect during operation life. Main aim of this paper is to introduce novel composite material designed for insulating system of high voltage equipment. This material is composed of epoxy resin matrix with dispersed magnesium oxide...
This paper presents a method how to simulate overhead DC network transmission losses that are estimated by a variable location of an electric vehicle regarding to an invariable location of a traction substation. Electric public transport infrastructure is one of the major electrical energy consumers. Electrical energy amount which is acquired due to overhead line voltage drop and current flowing through...
This paper presents a dual-mode CMOS integrated DC-DC buck converter for portable application. The proposed dual-mode buck converter is designed to be controlled by PFM (pulse frequency modulation) and PWM (pulse width modulation) modes. The converter for the application of wide current range and high power efficiency is used to generate the voltage of 0.5–3.0 V with the battery source of 3.3–5.0...
The paper presents a method for detecting non-linear high resistance earth faults in compensated medium voltage networks, based on the criterion of reactive power of higher harmonics of zero sequence current and voltage. Harmonics content of currents and voltages as the function of network parameters and nonlinear fault resistance was estimated. The model of earth fault protection using that criterion...
Night charging and fast charging are currently the two most common systems for charging electric buses. Despite the fact that numerous trial installations were started, neither of these two systems has obtained unqualified approval of the users. The alternative is to charge vehicles in motion (the so-called In Motion Charging), which combines the advantages of trolleybus transport and of electric...
This paper describes the design and prototyping process of outer rotor permanent magnet generator meant for the use in small scale wind turbines. The initial design of the machine is presented. Main issues and phenomena, affecting the generator design, such as cogging torque and its reduction possibilities, selection and demagnetization risk assessment of permanent magnets, machine losses and thermal...
In this paper is discussed and evaluated the using of various concept of traction drives in Czech Republic and in the World. The article is focused on application of innovative solutions especially high speed traction drives with permanent magnet synchronous machines. In the research is evaluated the impact of high speed application and assessed the advantages and disadvantages of the new concept...
This paper presents the analytical thermal analysis of a permanent magnet generator stator coil. The analytical analysis consists of a lump parameter thermal network (LPTN) to predict the steady state and transient temperature of the coil module. In the steady state part the average temperature of different parts of the network are estimated by using the matrix inversion and an iterative loop. In...
Paper deals with the analyses of electrical power network reliability parameters connected to maintenance. Knowledge of the component reliability parameters in power networks is necessary for the reliability computation and also for reliability-centered maintenance system. Component reliability parameters are possible to retrieve only with accurate databases of distribution companies. Such a database...
The paper deals with utilization of a photovoltaic power plant, installed on the roof of buildings within the Technological Centre in Ostrava (TCO) for production of hydrogen through electrolysis of water. The hydrogen produced will be stored in pressure vessels and used as fuel in fuel cells. The whole system of electrolysers for hydrogen production, pressure vessels for its storage and fuel cells...
In this work a study is carried out to improve the water pumping system, to be used to improve the electrical efficiency of photovoltaic panels by reducing the operating temperature of the modules. The methodology used modifications in the geometric height of the system and different types of pumping systems, with constant speed and variable speed using a frequency inverter. Through these changes...
Electric drainage is used to protect devices which are buried underground (such as piping) from the negative effects of DC electric traction induced stray currents. In places where stray currents leave the underground device and return into rails, they contribute to the corrosion of buried devices. Electric drainage is one of the possibilities to minimise these negative effects. Electric drainage...
This paper aim to analyze the action of the wind on photovoltaic panels installed on the roof of the building through computational simulation, considering different intensity of wind subjected to the installation. The intensity and direction of the flow combined with the photovoltaic panel inclination are strong factors for the occurrence of pressures that could cause accidents and damage that require...
The paper is focused on the possibilities of Mat-power toolkit within the phenomenon of delayed current zero occurrence. The analysis of delayed current zero and its effects are introduced along with the most important parameters playing the key role in the topic. Paper contains the Z-bus matrix evaluation within the Matpower toolkit and joints it with the DC components' generation and the danger...
Choice of materials is one of the most important steps during the development and design of electrical switching devices. Sufficient electrical and thermal conductivity, mechanical strength and environmental stability are the most important material properties for current conducting path. Contact area is the most critical part of the entire current-path. Nowadays, DC switching devices are more and...
The effective protection of each type of sensible electronic piece of equipment against any type of over voltage (including direct or indirect lightning applied on power supply) is a big issue for power system specialists. Some of the most reliable electronic devices used in order to protect against overvoltages are all voltage metal oxide varistor based surge-arresters. These varistors are produced...
This paper describes the Failure Mode and Effects Analysis (FMEA) focusing on tertiary side of (E)HV/HV/MV transformers and MV self-consumption subsystem of the Czech transmission power system. The goal of this FMEA is a) to identify all possible failure modes, which can occur in the examined system; b) to determine the impact of each failure mode on upstream (E)HV/HV system (referred to as FMEA I...
In connection with the development of infrastructure for electric vehicles (EVs) is in this article presented complex mathematical analysis of operation fast charging station (FChS) with integrated battery and by promoting of photovoltaic (PV) system. The goal of presented simulation of operating conditions was to demonstrate possibilities (advantages and disadvantages) of integrated batteries during...
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