Proceedings

Practical analysis of various techniques used in inrush blocking and restraining of differential relays for transformer protection

Rules induction-supported random forest for the non-intrusive electrical appliances identification

The paper presents the application of computational intelligence methods to the nonintrusive identification of electrical appliances in the household. The difficulty of the problem calls for implementation more than one algorithm. The presented two-staged methodology monitors the aggregated current level and includes the detection of the change in the state of appliances’ configuration with the subsequent identification of the device responsible for it. The latter uses the random forest as the main classifier and the rules induction algorithm as the supporting method to increase the...

Analysis of failure rates of AC and DC micro-grids

Nowadays dc distribution is gaining importance, as an increasing amount of loads is natively biased in dc. In addition, dc micro-grids are usually characterized by high efficiency and simple design. Moreover, they can better accommodate renewable generation and storage systems. These are the main benefits attributed to dc distribution grids. Reliability aspects, usually, are not sufficiently taken into account. This paper describes an initial methodological approach to compare (in both analytic and numerical way) ac and dc micro-grids. In particular, the analysis has been focused on the...

Analysis of the spectral degradation of LEDs emissions under temperature stress conditions

This paper presents the experimental results of an accelerated-life-test carried out on colored LEDs under temperature stress conditions. The main purpose of the work has been to investigate over the dependence of their reliability vs. their color. A deep analysis of the time variation of spectral components (RGB) under thermal stress has shown that the spectral components for each colored LED change in a different way over time. The main conclusion of this work is that the reliability of LEDs is strongly affected by the procedure and elements used for coloring the LED yielding to have...

Uncertainty-based combination of signal processing techniques for the identification of rotor imbalance

This paper describes a method for the uncertainty-based combination of signal processing techniques for the identification of rotor imbalance. The main idea of the proposed method is to compute the imbalance with different algorithms and to average their results. The method is based on the data fusion at feature level and uses the measurement uncertainty of the imbalance as a figure of merit for the weight computation. A static and a dynamic implementation are presented. In the static one, the weights are computed in a dedicated training phase, in which four algorithms (Fourier transform and...

Metrological Characterization of the Bunch Length System Measurement of the ELI - NP Electron Linac

Bunch length measurement in linac can be carried out using a Radio Frequency Deflector (RFD). A RFD provides a transverse kick to the beam introducing a correlation between the longitudinal coordinate of the bunch and the transverse coordinates, vertical or horizontal. So, through transverse beam size measurement on a screen, placed after the RFD, the bunch length can be obtained. In this paper, the metrological characterization of the bunch length measurement technique is proposed. The uncertainty and the systematic errors are estimated by means of a sensitivity analysis performed on the...

Measurement-uncertainty as an innovative management tool in modern engineering systems

In this work, a methodological approach based on the evaluation of the measurement uncertainty is used, in order to face the issues connected to the validation of measurements of distributed measuring systems, taking into account the requirements set by a scenario of high connectivity and big data. The methodology provided involves and follows from the rigorous methods applied in metrology discipline. It focuses on the measurement uncertainty evaluation, to be used as an innovative tool for better knowing the underlying systems/subsystems - from time to time analysed, towards...

Traceable Torque Calibration for Nacelle Test Benches in the MN·m Range

To verify all technical aspects of wind turbines, more and more nacelle test benches have come into operation. One crucial parameter is the initiated torque in the nacelles, which amounts to several MN·m. So far, no traceable calibration to national standards has been performed in such test benches. The paper will show calibration possibilities which already exist and also show future prospects.

A probabilistic method to assess uncertainty in vision based modal analysis techniques

This paper addresses the problem of estimating uncertainty when recovering the basic modal parameters of a given mechanical system using a generic vision based displacement measurement system. The particular nature of photogrammetry makes the calculation of uncertainty a challenging task because of the complex phenomena that occur during image formation (motion blur, optical aberration, etc.). To overcome this problem, a Monte Carlo simulation of the whole measurement process (including structure dynamics and its impact on image formation) is proposed. In this way, it is possible to retrieve...

Metrological self-check as a perspective trend of technical diagnostics

The need for changing a traditional procedure of metrological maintenance of measuring instruments (MIs) and multichannel measuring systems (MMSs) within an operation process, is growing quickly. It is practically impossible to realize the Internet of Things without the wide use of facilities that can provide increase in measurement results reliability and decrease of maintenance costs. The general features and opportunities of automatic diagnostics of MI and MMS health, are considered. Such diagnostics is called a metrological diagnostic check. It is noted that the standardization is a...