Indexes to evaluate risk based metrological performance in companies in the energy sector

The metrological performance evaluation is a tool that allows feedback in the management of measurements and the monitoring of the results achieved by the organizations that apply it. In many companies this type of evaluation does not show relevant results, mainly due to limitations in the procedures and indicators used to carry it out. The objective of this work was to develop metrological risk indices for the evaluation of metrological performance in companies in the energy sector. For the development of the research, three organizations belonging to said sector are selected. From the use in the organizations of the risk approach and interviews, document review, brainstorming and mathematical statistical methods, the metrological risk index and the risk index in metrological management are defined for companies in the aforementioned sector. The results achieved showed that it is possible to create this prototype tool, as well as its usefulness to provide feedback on the management of measurements, in addition to guiding the management decision-making process in metrological matters.

Unsteady force measurements on propeller model in cavitation tunnels

Object and purpose of research. This paper discusses longitudinal unsteady force dynamometer for cavitation tunnel tests. The purpose of the study is to improve metrological performance of the dynamometer and extend the scope of its application. Materials and methods. The study is based on metrological parameters of dynamometers and model test data available with KSRC Large Cavitation Tunnel (LCT). Main results. Development, manufacturing, certification and commissioning of longitudinal unsteady force dynamometer based on piezoceramic load cell with improved metrological performance making it applicable for model testing of not only propellers but also other types of marine propulsors. Conclusion. Dynamometer with piezoceramic load cell offers more accurate measurement of unsteady forces, wider band of measurement frequencies, as well as wider spectrum of possible applications and lower susceptibility to interference.

Numerical study using finite element method for the thermal response of fiber specklegram sensors with changes in the length of the sensing zone

The response of fiber specklegram sensors (FSSs) is given as function of variations in the intensity distribution of the modal interference pattern or speckle pattern induced by external disturbances. In the present work, the behavior of a FSS sensing scheme under thermal perturbations is studied by means of computational simulations of the speckle patterns. These simulations are generated by applying the finite element method (FEM) to the modal interference in optical fibers as a function of the thermal disturbance and the length of the sensing zone. A correlation analysis is performed on the images generated in the simulations to evaluate the dependence between the changes in the speckle pattern grains and the intensity of the applied disturbance. The numerical simulation shows how the building characteristic of the length of sensing zone, combined with image processing, can be manipulated to control the metrological performance of the sensors.

Characterization Procedure for Stand-Alone Merging Units Based on Hardware-in-the-Loop Technology

The digitalization of a medium voltage network requires huge efforts from distributed system operators and electric utilities. The main reason is attributed to the costs associated with the replacement or introduction of new intelligent electronic devices capable of collecting and digitalizing current and voltage measurements. To this purpose, this paper introduces a new idea of a stand-alone merging unit (SAMU), which features real-time and hardware-in-the-loop technology, completed with accurate voltage and current sensors. Furthermore, the characterization procedure that allows an evaluation of the metrological performance of a complex device, such as a SAMU, is fully described. From the results, it is highlighted that (i) the developed SAMU is capable of performing highly accurate voltage, current, and power measurements; (ii) the characterization procedure is simple and exploitable for all kinds of SAMUs and other synchronized measurement devices.

Evaluation of the Metrological Performance of a Handheld 3D Laser Scanner Using a Pseudo-3D Ball-Lattice Artifact

This paper proposes the use of a pseudo-3D ball-lattice artifact to characterize a handheld laser scanner from a metrological standpoint. The artifact allows the computation of local and global errors in measurement by using the reference-frame-independent parameters of size, form, and distance within the measuring volume of the scanner, and in a single point cloud, without the need for registration. A set of tests was performed using the whole measuring volume, and three acquisition parameters, namely the orientation of the sweeps during the scans, the exposure time, and the distance to the scanner were analyzed for their effects on the accuracy of the scan data. A composite error including the errors in measuring size, form, and distance was used as a single figure of merit to characterize the performance of the scanner in relation to the data-acquisition parameters. The orientation of sweeps did not have a considerable effect on the errors. The accuracy of the scan data was strongly affected by exposure time and its interaction with the distance at which the artifact was scanned. The errors followed a quadratic trend with respect to the distance of the artifact to the scanner. The tested scanner performed best at its manufacturer’s recommended stand-off distance.

A fuzzy evaluation method of road vehicle automatic weighing instrument in dynamic force metrological performance

The measurement performance of road vehicle automatic weighing instrument installed on highways is directly related to the safety of roads and bridges. The fuzzy number indicates that the uncertain quantization problem has obvious advantages. By analyzing the factors affecting the metrological performance of the road vehicle automatic weighing instrument, combined with the fuzzy mathematics theory, the weight evaluation model of the dynamic performance evaluation of the road vehicle automatic weighing instrument is proposed. The factors of measurement performance are summarized and calculated, and the comprehensive evaluation standard of the metering performance of the weighing equipment is obtained, so as to realize the quantifiable analysis and evaluation of the metering performance of the dynamic road vehicle automatic weighing instrument in use, and provide data reference for adopting a more scientific measurement supervision method.

Design and Characterization of a Stand-Alone Merging Unit

<p class="Abstract">Merging Units (MUs) play a key role in enhancing the levels of security and the reliability of power systems, allowing for advanced remote diagnostics. Some of the benefits are a more efficient transmission of electricity and a better integration with renewable energy systems. In this article, an implementation of a Stand-Alone Merging Unit (SAMU), compliant with the IEC 61850-9-2 standard and based on a low-cost ARM microcontroller, is described. It acquires two signals, one voltage and one current, and it sends the samples over the ethernet connection. A high-resolution Analogue-to-Digital Converter (ADC), synchronised to the Universal Time Coordinated (UTC) through a Global Positioning System (GPS) disciplined oscillator, is used. The opportune insulation and conditioning stage have been designed. Several tests have been performed, varying amplitude, frequency, and phase of the input signals, in order to evaluate the metrological performance of the proposed SAMU and they are here discussed.</p>