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The article describes using of power semiconductor converters in the area of accumulation of electrical energy in the Technology Centre Ostrava (TCO). Further discloses design of the power semiconductor converters, its internal structure, utilization of energy and the main parameters and focuses on the issues of the capacitor bank — determine the power loss of capacitors, determine the lifetime, determination...
Because of the financial savings and with respect for the environment, several efforts are made to replace AC voltage long distance transmission lines for DC voltage transmission lines. This may lead to increases of charging of insulation materials. The main aim of this paper is to describe the space charge accumulation in insulation material and its effect on local overloading of insulation material...
Automated parking system (APS) is a mechanical system designed to minimize the area and/or volume required for parking cars. It is a solution for areas with a minimum place to parking, especially in city center. Sometimes there are some APS which are equipped with charge station for E-vehicle. Respecting power consumption of APS and possible charging stations there should be a problem with supply...
In this paper, the problem of optimal power flow (OPF) is solved in a system integrated with wind farms with the aim of reducing the cost of power production and the reduction of power grid loss by applying the Grey Wolf Optimization (GWO) Algorithm. The variable nature of wind farm output is modeled using two additional cost components corresponding to the states of under estimation and over estimation,...
The reduction of active power losses in transmission lines of modern power supply systems by solving the problem of reactive power compensation is an important task. The efficiency of the compensation depends on the choice of powers and placement of compensation units in nodes of a network. The task considered is the multi-objective and multi-factor optimization problem, and the time required to solve...
The paper discusses the impact of microgeneration on the energy quality in a low-voltage (LV) network. Expressions are formulated for obtaining voltage deviations and fluctuations caused by microgeneration sources. Simulations are carried out to predict the impact of microgeneration on voltage drops in nodes of low-voltage lines.
This paper aims to identify the critical line on the basis of power system cascading failure search. The proposed critical line identification strategy considers the factors of power flow and topology. Accordingly the electrical betweenness and transmission power are employed during analysis, of which the corresponding theoretical basis is deduced in simple systems. Next follow-up step is to apply...
This paper's purpose is to investigate the energy efficiency with the installation of the photovoltaic system in residences of social interest, seeking mainly to meet the demands of higher consumption of electric energy such as the showerhead. An estimatedproposal of the Energy Efficiency Program carried out by the Goiana Housing Agency in which it will install 1,199 photovoltaic systems in the housing...
This paper deals with estimates of capacity between rails of the traction tracks. The determination of capacity was performed using software for numerical processing of electromagnetic fields: QField, COMSOL, together with the ATP program. The model comprised a traction section with the track clearance of 10 cm above the ground. The result then provides the estimate of capacity changes between rails...
The paper focuses on the charging of LiFePO batteries with big output voltage. This voltage is necessary to feed a frequency inverter circuit with approx. output of 7.5 kW. This is a part of the solution applied during the Pre-seed project solved in the past at VSB — TUO Ostrava. Due to the unavailability of standard chargers, we provide a solution based on the Siemens 6RA80 controlled rectifier.
This paper deals the mathematical description of an asynchronous machine. Differential equations are then used to create a dynamic model of asynchronous machine. For the possibility of evaluation the quality of the created model are created at the conclusion the basic characteristics of representing the asynchronous machine. Graphs show almost identical measured and the simulated values. The model...
In this paper the switched reluctance generator (SRG) is explored considering the improvement of its efficiency. This machine generates a DC power that is directly related to input driving parameters. Simulation results are presented bringing a case study of parametric regression to track the best efficiency for any input parameters: excitation voltage and turn off angle. A method known as parametric...
Waste engineering wood in the form of chipboard and plywood is a potential source of renewable energy in boilers for biomass combustion. The conditions causing the silicate melt slagging during combustion were studied by proximate analysis, mineralogical analysis using X-ray diffraction, scanning electron microscope with energy dispersive analyser and thermogravimetry. Slags are formed by refractory...
Congestion management is one of the technical challenges in the power system. Privatization and market liberalization lead to stressed operating conditions in existing and future power systems. Additionally, the increasing complexity of the power system results in an increased need for information on the actual grid condition and intelligent control methods. Unfortunately, measurement data from each...
This paper presents a speed control for a DC motor. Despite the unknown parameters of the plant to be controlled, these parameters are found using a system identification method. The methodology implemented in this study is known as parametric regression and is based on an optimization technique. This optimization, through its fitness function, allows to find the system characteristics in order to...
Computational fluid dynamics (CFD) is appropriate method to analyse aerodynamic flow in wind turbine. This is why we choose this method to compare static torque characteristics of two vertical axis wind turbines (VAWT), one with straight blade and the other one with helical blade. Analyses are realized by use of Ansys CFX software. At first, three-dimensional (3D) simulations of straight blade turbine...
This article discusses application of photovoltaic panels thermal features into complex numerical model. Heating of the panels affects power output and efficiency. This process depends on weather conditions including fast variations of solar radiation. Typical models of PV systems do not speculate about these fast changes. Analysis and simulation of this transient phenomenon is result of this research...
This paper presents possibilities to increase the efficiency of three-phase squirrel cage induction motors. The necessary legislative requirements are stated in the first part of the paper, which are basically the main reason for efficiency increasing. After that a theoretical basis and explanation of the design for efficiency increasing follow. The final part presents the results of measurements...
This paper presents an induction motor drive using a method of direct torque and stator flux control. One disadvantage of the algorithm is a variable switching frequency of a voltage source inverter although it is used a constant period for the direct torque control processing in a digital signal controller. It is difficult to carry out a good filtration of the variable switching frequency; therefore...
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