Search results for "transformer"
showing 10 items of 96 documents
A portable instrument for the location and identification of defects generating PD
2011
A portable instrument based on an antenna probe and suitable for partial discharge detection, have been characterized through both laboratory and on-site experiments carried out on coils and stator windings of ac rotating machines. The antenna probe allows the capture of electromagnetic waves in a bandwidth of 0.1–100 MHz. Pulse signals and ac supply voltage reference are obtained by means of high-pass and low-pass filters, respectively, so avoiding the need of a direct connection with the objects under test. By this way, real-time phase resolved partial discharge patterns can be derived. Results of a comparison of the diagnostic information provided by PD patterns due to conducted and irra…
On the use of narrow band power line as communication technology for medium and low voltage smart grids
2012
The aim of this work is to perform a feasibility study on the power line communication for the development of a new generation of interface devices (IDs) for smart grid applications. More in detail, this paper deals with one of the most important issues on this topic which is the communication system. Among the existing communication technologies, the study is focused on power line communications (PLCs). After a analysis of the state of the art in the field, the main aspects are analyzed, concerning the open issues on the use of PLCs, especially for medium voltage (MV) and low voltage (LV) systems. In this work the use of PLC in MV-LV networks is investigated, by means of simulations and ex…
The analysis and selection of the spinning disk system parameters for the measurement of static electrification of insulation oils
2007
The paper presents results the aim of which was determining the most favorable conditions of ECT (electrostatic charge tendency) measurement taking of insulation oils in the spinning disk system. The work proved that a proper selection of the size and roughness of the disk surface makes the measured volume density of charge qw independent of the hydrodynamic conditions in the measuring system on the solid and liquid phase border. Charge qw density meets then the criterion of a material coefficient and can be used for comparing the results obtained from the systems varying in dimensions and hydrodynamic conditions. The changes suggested also ensure a high repeatability and reproducibility of…
The impact of fixed and moving scatterers on the statistics of MIMO vehicle-to-vehicle channels
2021
©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Article also available from publisher: http://dx.doi.org/10.1109/VETECS.2009.5073879 In this paper, we study the impact of fixed and moving clusters of scatterers on the statistics of multiple- input multiple-output (MIMO) vehicle-to-vehicle (V2V) channels. Double-bounce scattering is assumed for fixed scatterers, while single-bounce scattering is considered fo…
PMSM Drives Sensorless Position Control with Signal Injection and Neural Filtering
2009
Vector Field Oriented Control (FOC) is one of the best control methods for high-dynamic electrical drives. To avoid the adoption of the speed/position sensor (resolver/encoder), a sensorless technique should be used. Among the various sensorless methods in literature, those based on machine saliency detection by signal injection seem to be most useful for thier giving the possibility of closing the position control loop. This paper proposes a method for enhancing both rotating and pulsating voltage carrier injection methods by a neural adaptive band filter. Results show the goodness of the proposed solution.
Medium Voltage Smart Grid: Experimental Analysis of Secondary Substation Narrow Band Power Line Communication
2013
This paper is focused on the possibility of employing narrow band power line communication (PLC) in medium voltage (MV) distribution networks. The topic is investigated by means of both simulations and experimental tests, which were carried out in the distribution network of Ustica Island. In detail, a two-way MV communication was tested between two secondary substations connected by an MV cable power line. Each substation has a by-pass connection at MV bus-bars and an MV/LV oil filled power transformer. In this paper, the MV and the PLC systems under test are described and the experimental tests are presented, which were carried out to evaluate the parameters of the simulation model. The a…
Parameterizing non-linear magnetic cores for PSpice Simulation
2005
Abstract. In this paper the main Jiles & Atherton parameters of a magnetic material, according to their particular working condition (mainly frequency, temperature and waveform) are calculated by means of a systematic procedure that use PSpice and MathCad. The modelled magnetic material is used for power electronics circuit simulation, which uses magnetic materials, working at frequencies in the region of kH, to construct transformers and inductors. Magnetic materials are the most critical components in electronics simulators due to their nonlinear behaviour and the accuracy in the simulation can only be obtained through a proper magnetic material modelling. This paper examines the modellin…
Obtaining the electrical model of a power transformer by means of finite element software
2005
Abstract. The behaviour of transformers and inductors working at high-frequencies and high power density can dramatically differ from the ideal or low-frequency operation. Their performance is very dependent on the magnetic material, operating frequency and physical construction. In this paper, finite element analysis (FEA) is used to obtain an accurate characterization of the electromagnetic behaviour of these magnetic components.
A back to back method for the temperature rise test of prefabricated substations: A case study
2015
In this work a back to back method is presented which allows to develop heating tests of prefabricated secondary substations with a limited number of supplying equipment (an induction regulator and a capacitor bank). The proposed method makes use of the transformer tap changers to create a voltage difference on the medium voltage side. In this way, only an adjunctive low voltage supply is needed. With the proposed test system, the heating tests are developed on a 1000 kVA prefabricated substation. Thanks to the experimental tests, the class of enclosure of the substation and the operating temperature and resistance of the power transformers are determined, according to the recommendations o…
Characterisation of electric alloys for electric drives
1996
Knowledge of the magnetic and loss charactenstics of electric alloys is necessary for the computation and design of electrical machines. Over a long period of time, and more recently, many devices have been proposed for this characterisation. They test ferromagnetic sheets under conditions of unidirectional magnetic flux density. Other methods are derived from some of these devices, but they use conditions of rotating flux density. In the paper the authors show with the use of numerical computation that, in all these testing systems, the distribution of the magnetic flux density through the thickness of the sheet is uniform and does not take into account the edge effect which exists in rota…