This paper analyzes accuracy of algorithms commonly adopted in instrument devoted to the detection and the characterization of voltage dips (also called sags). This analysis is particularly interesting because the results of dip measurements are utilized for calculation of severity levels and the site index assessment that are parameters adopted in determination of quality level of power supply, but also in developing planning and design criteria of new electrical power grid or for selecting equipment with proper intrinsic immunity. Anyway there is a certain degree of freedom left to...
In this paper we present some algorithms for devices with limited energy resources that are forming ad hoc wireless sensor network. Proposed Challenge-Answer MiniProtocol (CAMP) is a clustering and gradient-based protocol with all-to-sink and sink-to-all transmission style, derived from directed diffusion idea. It deals with challenges such as variable quantity of working nodes which are constituting a network, hot-spot problem and power resource constraints. Tests of network using CAMP are presented and discussed.
In this paper an analysis of conducted harmonic emissions of different types of lamps is presented. The growing use of non-linear loads (pc, printers, electronic devices, etc.) connected to power supply systems and their variability with time, are responsible of a continuously changing harmonic content in the distribution system. Therefore, to analyze their real behaviour, the lamps were tested using the general power supply of an office building as the source voltage, so that the harmonic distortion of the test voltage changed depending on the time of day and on different weekdays....
The paper presents the implementation of accelerated impedance spectrum measurement method, oriented for technical objects modelled by a linear equivalent circuit, e.g anticorrosion coatings. The method is based on multisine signal stimulation of an object and response analysis by triangle window filter-banks. It has several advantages, as compared with conventional point-by-point spectrum measurement. The method was implemented in an experimental measurement system, based on a DAQ card. The achieved experimental results are discussed and compared with simulation results, in terms of...
Two acquisition techniques pointed out for the static and dynamic test of high resolution DAC by low resolution ADC are analyzed and compared. These two techniques differ on the basis of the specific approximated evaluation of the DAC output voltage. The interest to the comparative analysis is justified by the aim to separate the influence of the acquisition technique from that of the processing algorithm on the evaluation of the accuracy of the test. The comparing analysis is performed on the basis of the accuracy to reconstruct the output signal of the DAC. The error occurring in the...
The Accredited Laboratories at their Certificate have described its best measurement capabilities (BMCs)1 for the more or less routine calibrations. This BMCs were usually evaluated by interlaboratory comparisons (ILCs), the proficiency testing (PT) schemes as described by the ISO Guide 43. The NMIs traditionally organize the ILCs for the NABs providing the travelling standards, the reference(s) value(s) and at the end perform the statistical analysis of the laboratory results. The goal of this article is to discuss the existing approaches for ILCs evaluation in the calibration laboratories...
Cloud height, wind speed and direction at cloud height play an important role in air safety. This paper presents a low-cost system based on digital consumer cameras to estimate cloud base height. It is shown that both wind speed and direction at cloud level can also be obtained with this system. The method is based on triangulation and uses image registration to identify common cloud features in photographs taken from different positions. The wind speed and direction is obtained from two time-lapsed pictures taken from the same position.
An inductive dynamic drive is nowadays a commonly used servo-motor everywhere where a significant dynamics of the linear displacement is required. In industrial environment the dynamic drives are commonly used in ultra fast hybrid switches for opening the contacts. At the same time, choice of the parameters and type of power supply of the drive coil, which influence the generated power is very important due to possibility of occurrence of unfavorable vibration and even permanently deformation of the disk. The paper presents the results of an experimental research concerning the inductive...
The paper describes some problems connected to the reference data set generation for the validation of metrological software. The validation concerns the Gaussian procedures for solving the task of the approximation of geometric features.
The paper is to present the new DSP-based device shown in the wake of hitherto development of power quality instrumentation for power quality assessment in ship systems. The basic features of the new power quality estimator-analyser are described. Further, the design of its new commercial version is shown and discussed.