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The specific problems of the disconnection of HVDC breakers need an analysis of performances at laboratory scale. In the study of hybrid circuit breakers with commutation, three steps are necessary: modeling, simulation and experimental tests. The paper presents a modeling procedure for a hybrid commutation breaker intended to operate using resonant circuits phenomenon. Using the Matlab platform,...
The paper presents a few issues generated in low voltage distribution grids at the end user's level, by power system harmonics. The introductory section presents shortly harmonics sources, their analysis, effects and measurement methods, appealing mainly to the limits depicted in the specific standards. The following section presents two case studies of power electronics equipment drawing high distorted...
Water resource availability is an important problem as water is basically used for everything we make. In a water distribution process the level and flow must be always controlled. Therefore, the parameters of the system must be known at any moment. This paper presents an automatic level control system which is analyzed in terms of reliability in order to present solutions to clarify how such systems...
Speaking about the commutation's equipment, it can be said that the best solution in increasing reliability and lowering the maintenance costs is a continuous monitoring of the equipment. However, if the price/quality ratio is considered, it is obvious that, for the moment, the diagnosis can be also an acceptable solution. Nowadays the predictive maintenance for equipment's diagnosis is currently...
The paper presents the assessment of electromagnetic compatibility of adjustable drives used in residential air conditioning systems (i.e. air handling units, systems that conserve a significant amount of energy, while maintaining indoor comfort) with a particular stress on brushless DC motors. In the introductory section, a recall of the new smart power modules, that drive centrifugal fans provided...
Several fixed frequency applications of multilevel converters require a very low level of distortion factor of the output voltage. Bringing the output voltage to a form as close as possible to a sine wave is usually done through linearization methods of the Newton-Raphson algebraic equations. The method proposed in section III uses for the waveforms optimization a genetic algorithm, having a positive...
This paper approaches the electromagnetic design and finite-element analysis of an axial-flux permanent-magnet (AFPM) synchronous generator for small-scale wind turbines. The study is conducted to find a good-performance and cost-effective electric generator topology for micro-wind power application. The proposed double-sided two-stators-one-rotor AFPM synchronous generator with non-overlapping concentrated...
Monitoring of electrical equipment is a direction of current development in the maintenance domain. The method aims to establish the operation state of the monitored equipment. Fault diagnosis existing on power circuit breakers is very important aspect in emergency situations, when it must be interrupted by high current circuit breakers. This paper presents a model of vibration monitoring using Wavelet-Morlet...
The paper presents a few aspects of power quality at the supply port of power electronic converters. The main point is that the lack of power quality, especially in the case of a large harmonic content, leads to conducted electromagnetic interference. The approach focuses mainly on the methods of assessing conduced electromagnetic interference. At the same time the methods of testing in laboratory...
The paper presents the monitoring of the power quality of an underground electric line fed by a high voltage transformer station 110/10 kV and a subsequent earthing fault situation followed by a short circuit. The monitoring process was performed using a power quality analyzer. The analysis of the evolution in time of the phenomena highlights the variations of the voltage in the medium voltage bus...
The paper presents the implementation of a software for the analysis of vibration generated by wind turbines components. This software application has been built in the LabVIEW programming environment. For the vibration analysis and fault detection have been used several techniques, like: wavelet analysis, envelope detection, FFT analysis, Cepstrum analysis, Vector RMS analysis. Vibration signal envelope...
This paper aims to evaluate capabilities of axial-flux and radial-flux permanent-magnet machines. The comparison is done exclusively from an electromagnetic point of view. The electromagnetic design comparison of conventional radial- flux and axial-flux topologies is carried out in view of traction drive applications.
EMI - Electro Magnetic Interference-filtering represents an anti-distortion measure used in the mitigation of the conducted interference, i.e. electromagnetic perturbations on the supply cord, data or signal lines. The paper reviews the design of the magnetic circuit of a three-phase EMI filter, neglecting the displacement current. The designed EMI filter is meant to mitigate harmonic components injected...
This paper presents a method for limiting short-circuit current for d.c. systems. Classic methods for limiting short-circuit current are described as well as solid state devices used directly on current path and by-pass solutions. Thyristor and resonant circuit breaker version proposed by authors relieves current flow for every step during operation. Matlab simulation for these steps is useful for...
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