Influence of the Selection of the Core Shape and Winding Arrangement on the Accuracy of Current Transformers with Through-Going Primary Cable

The current transformers with split-core are used for installation in places where it is impossible to install classic current transformers. Moreover, this design allows for any measurement location change, and even switching one current transformer into several different shapes of bars or cables. Power network operators, striving for more accurate current measurements, require producers to provide current transformers with a special accuracy class 0.2S. Therefore, manufacturers and designers try to meet the market requirements and, similarly to non-demountable current transformers, i.e., with a toroidal core, design current transformers with split-core class 0.2S. To meet the high metrological requirements, 3D analyses of electromagnetic fields were performed, taking into account physical phenomena and not approximate analytical models. Two types of cores and four different arrangements of the secondary windings of the measuring current transformers were considered. The magnetic field distributions, current error, and phase displacement diagrams of all current transformer models were analyzed, and the model of the transformer structure with the best accuracy was selected. Computations were conducted based on the finite element numerical method, and the results were compared with the real model tests.

METROLOGICAL REQUIREMENTS OF WEIGH-IN-MOTION SYSTEMS FOR VEHICLES

The article analyzes and proposes solutions for metrological support of weight information systems of road vehicles in motion, including the method of classification of WIM systems by purpose and accuracy classes, metrological requirements for them and control methods for testing and verification, as well as the main metrological risks for Weigh-in-motion systems for road vehicles and requirements for determining and calculating reliability.

Complex control of coordination and speed-power abilities in fire-applied sports

Background and Study Aim. To identify informative tests for complex control of coordination and speed-power abilities in fire-applied sports. Material and Methods. 38 experienced firefighter-athletes aged 15-17, who have been doing this sport for 5-6 years, took part in the research. The survey of Russian leading coaches allowed us to make up a bank of 20 tests. The Brave-Pearson correlation coefficient was used in the statistical processing of the results. The research results were processed using the Excel program. Results: Methods of controlling coordination and speed-power abilities with competitive result when overcoming a 100-meter obstacle course in fire-applied sports were experimentally substantiated. In accordance with the basic metrological requirements, close correlation relationship was found for 10 tests. Conclusion: Fire-applied sports is a complex technical type, to control the development of coordination and speed-power abilities it is necessary to rely not on one test, but on a bank of them. The identified informative tests can be recommended for complex monitoring of coordination and speed-power preparedness in fire-applied sports.

3D Electromagnetic Field Analysis Applied to Evaluate the Accuracy of a Voltage Transformer under Distorted Voltage

Voltage transformers (VTs) are an important element of the measuring system that allows measuring the energy flow in medium and high voltage networks. Additional problems with the accuracy of the measurement introduced by the appearance of sources and nonlinear receivers cause deformation of the voltage shape in the energy system. Due to the high metrological requirements, the design of voltage transformers requires high accuracy (for class 0.2 ΔU ≤ 0.2, phase displacement ≤10 min), which is not possible with the use of analytical methods using approximate models. Therefore, only the application of numerical modeling by the finite element method, taking into account real three-dimensional phenomena, allows achieving high modeling accuracy. The article concerns the phenomenon of the influence of voltage higher harmonics of supply voltage on the accuracy (up to the 100th harmonic) of the measuring inductive voltage transformer (IVT). The applied modeling method takes into account the phenomena in the transformer core and the circuit equations resulting from the winding arrangement, which allows for the study of the deformation voltage transformation. Experimental tests on a real model to evaluate the method used were necessary. The article presents simulations for a model transformer, and results have been confirmed by experimental tests.

Features of the technique of lateral hand blow at close range of highly qualified athletes specializing in hand-to-hand combat

In this article, on the basis of video filming and biomechanical video computer analysis using the "Qualisys" optoelectronic system, the features of the lateral hand strike technique at a short distance of highly qualified athletes specializing in hand-to-hand combat are determined. Our data made it possible to establish that the hand strike technique at close range is individual for highly qualified athletes. At the same time, the general dynamics of changes in individual indicators was found. So, after accepting the initial position, the movement of a highly qualified athlete begins with a rather active advancement of the right side of the pelvis, as well as the hip joint forward-down-right. At the same time, the opposite movement of the right shoulder joint is observed – back-down-left, which leads to a turn and tilt of the athlete's body back. Modern video recording systems allow obtaining objective quantitative characteristics of the athlete's body movement, fully satisfies the necessary metrological requirements for biomechanical analysis, synthesis and modeling.

Analysis of Metrological Requirements in Occupational Health and Safety Regulations Related to the Emerging Risk of Exposure to Vibrations

In occupational exposure to vibration, the risk assessment process is defined through a regulatory framework that presents some relevant metrological problems. This framework considers methods based on estimation and on measurements. Estimation methods could employ existing information that is provided for each manufacturer to each individual tool or application to carry out such estimation. The use of estimation methods has some problems, such as substantial uncertainty. When using measurement methods, some metrological aspects are not fully defined. Therefore, a new and emerging risk appears due to certain methodologic limitations. Consequently, the variation between the estimated and the actual values could overestimate the level of occupational exposure to vibrations. Thus, with this paper, a critical analysis of this emerging metrological problem is provided. For this, a critical analysis of the metrological requirements regarding European standards is developed. To this end, the estimation method and measure method are investigated, considering, in both cases, the main factors related to uncertainty, reliability, and traceability. With this structure, a set of metrological limitations have been identified, thus pointing towards future lines of research that allow the improvement of the process of assessing the level of occupational exposure to vibrations.

Metrological Activity At the Enterprise

When organizing metrological activity at an enterprise, the question arises of the need to organize verification (metrological confirmation) of measuring equipment that is not used in the field of legislatively regulated. In the international standards «Quality Management Systems» (ISO 9001, EN 9100, AQAP-2110), to ensure that the requirements of Section 7.1.5 «Resources for Monitoring and Measurement» are met, the requirement is established that all measuring equipment, as part of a measurement management system, must have metrological confirmation in accordance with the requirements of ISO 10012. Metrological confirmation provides for the calibration and verification of measuring equipment. Laboratory specialists who carry out metrological confirmation of measuring instruments, establish a relationship between the values of the values that provide the standards, and the result of measuring this quantity using measuring instruments (carry out calibration), based on this ratio establish the conformity / non-compliance of the measuring instruments with the established requirements (carry out verification) and draw up the corresponding supporting document. After comparing the concepts of metrological confirmation and verification of measuring instruments, we can conclude that metrological confirmation (calibration and verification) of measuring equipment is essentially nothing more than verification of measuring instruments. Metrological activities to ensure the uniformity of measurements in enterprises should comply with the requirements of ISO 10012: 2003. This standard establishes general requirements and contains recommendations for the management of measurement processes and metrological confirmation of the suitability of measuring equipment, which is used to maintain and demonstrate compliance with metrological requirements. Compliance with the requirements set forth in the ISO 10012 standard makes it possible to ensure compliance with the measurement requirements and the management of measurement processes established by the international standards «Quality Management Systems».

Quantitative analysis by Raman spectroscopy using potassium hexacyanoferrate (III) as an internal standard

In this article we proposed a method for quantitative determination of active substance in pharmaceuticals via Raman scattering using potassium ferricyanide as internal standard. We approved this method in ketoprophenum quantitative determination in drug for veterinary use “Ketojekt”. The calculation of metrological requirements of procedures are established proposed method of calibration. Either we demonstrated the focalisation factor of laser beam affects on the method reproducibility. The method provides a precise, rapid, convenient to quantitative analysis that is more effective than the standard HPLC assay.