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This paper aims to presents an overview of electrical contact resistance. The electrical contacts are important elements which can be found on all of the electrical installations from the power source to the consumer. The presence of an electrical contact on a current path always introduces an additional electrical resistance, named contact resistance. After an overview of the role of the contacts...
The purpose of this paper is to present the modeling results consists in the computation of the electric potential in 3D applications involving moving interfaces using mesh free methods. The eXtended Finite Element Method (XFEM) is used to numerically approximate the electric field problem while the Signed Distance (SD) function is used to determine the position of the moving interface inside the...
The paper develops a spectrum localization method for the symmetrical components of a three-phase, unbalanced systems, in non-sinusoidal regime. Spectral density of symmetrical components is determined in relation to the spectral density of the analytical signals associated to voltage and current signals of the three-phase systems. The method allows determining the direct and inverse sequence of components...
This article describes the results of the European Project Empower. This project is about the creation of a trading platform for local energy exchange in local markets. To do so, a system architecture is proposed, based on the Smart Grid Architecture Model (SGAM). The implementation of the developed platform has been tested in the Prosumer Lab environment. The Prosumer Lab is an installation at the...
The capabilities related to active filtering of the Stationary Wavelet Transform — SWT were evaluated considering 3 Daubechy wavelet mothers. Firstly a study on errors was performed on synthetic waveforms. The waveforms were obtained from sinusoids polluted by single harmonics with orders from the range 3…40 and magnitudes, respectively phase differences varied in a systematic manner. The differences...
Today, the stability of the power distribution system is influenced by the significant number of photovoltaic power plants connected to the electric distribution network. This paper aims to present the results obtained after about three years of operation of a photovoltaic plant of 2.8 MW in terms of voltage variation in the common point of connection, power quality. Also, will present results of...
The controlled switch became a technical solution for reducing the switching stress. The controlled switching can be applied to any type of commutations. There are now dedicated controllers which are used more often for the switching of the transport and distribution lines, of the small inductive loads, of the capacitors batteries, or for energizing the no load power transformers. The paper deals...
The present study proposes an artificial upper limb prosthesis simulation that combines elements of electric engineering (sensors, data acquisition / transfer, servo-motors) and virtual instruments programming technique (LabVIEW). Since we are in the process of working on a prototype of the prosthesis, the paper presents a model that enables the movement of a single phalanx, operated by a LabVIEW...
Experiments were conducted to illustrate the performance of a flywheel energy storage system (FESS) for electrical engineering technology students. The flywheel was coupled to a permanent magnet synchronous machine (PMSM), which can motor to accelerate the flywheel, and which can regenerate electrical power by extracting energy from the flywheel. The PMSM was connected to a battery bank and DC motors...
Urban Energy Management approach of Cluj-Napoca city municipality is presented in close connection with the public utilities companies, energy action plans and mainly the impact on energy use on public building in an original approach between the City Municipality — Technical University and an NGO founded by the private energy companies.
Implementing the spiral inductors in the radiofrequency micrometric integrated circuits is complicated, therefore some prior studies in order to determine their optimum configurations for the circuit in which they will be implemented are necessary. This study is a step forward in the study of spiral inductors, aiming at comparing the monolayer to the multilayer spiral inductors in order to determine...
The article describes the requirements for medium-voltage switchgears. It shows the main advantages and drawbacks of the conventional air-insulated switchgears and the relevance of the switchgears with solid insulation and solid shielded insulation. The use of this insulation system allows to reduce significantly the size of switchgear and to improve considerably the safety of its operation. The analysis...
With the evolution of IEC 61850-9-2 based Process Bus & IEC 61850-8-1 based station bus and the possibility of various architectures, it is important that the protection system be assessed or evaluated for its performance on real time fault conditions. Current differential protection stands out as it works across multiple substations and multiple line ends, with the variants mentioned below: a)...
This paper proposes the ferrite magnet-assisted synchronous reluctance (FMASR) machine topology for use as direct-driven generator in low-speed micro-wind power applications. The FMASR generator consists of a stator core hosting three-phase distributed winding, and a transversally-laminated rotor having multilayer flux-barriers with embedded FMs in flux-concentration arrangement. Analytical model...
There are presented the results of the research of the efficiency of multi-agent management of voltage mode in electric grids, diagrams of power delivery of power stations. In the structure of devices for voltage regulation in a controllable area, there was considered the use of the normalizer of AC voltage, in particular as the means of emergency control, controlling the stability of motoring load...
The design process of a rectangular waveguide pyramidal horn antenna is carried out. A mathematical design algorithm is developed and implemented in Matlab. The antenna model is built afterwards, accounting for the same computed parameters, with two different dedicated antenna design and simulation software packages: CST Microwave Studio and ANSYS HFSS. Both are based on the Finite Element Method...
The paper performs a load analysis in a Romanian substation. To respond to the increasing energy demand, consumption relocation and to reduce internal losses the substation has been recently retrofitted replacing old IO type circuit breakers with new gas insulated SF6 switchgear. The paper performs numerical analysis of the internal substation power flow and power losses for different working scenarios.
The traction current is returning to the supply source crossing the return circuit to the 25 kV single-phase AC power source. The return circuit consists of the running rails, which are connected by conductors to the joint coils terminals, and the return feeder to the traction substation. The connecting conductors (connection ropes) are subjected to thermal stresses due to the intense currents which...
The authors have been developed a number of solutions in heliothermic actuators and motors area made on the basis of solid heating medium. The paper presents the authors contributions on the development of solar actuators with bimetallic band. In the end of the paper are presented the main conclusions about testing and practical implementation.
This paper presents how to implement the finite element method (FEM) to determine the magnetically coupled coils parameters. The method is applied for computing the parameters of the two resonators used in wireless power transfer (WPT). To compute the parameters corresponding to the resistance, self inductance, capacity and mutual inductance (R, L, C and M), we used CEDRAT Flux 2D software. The results...
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