Accuracy Class Research Articles

Economic damages from low-quality electric energy

The problems of maintaining the quality indicators of electrical energy and, in particular, voltage dips as well as the consequences of voltage dips in electrical networks of industrial enterprises are considered. A classification of electrical consumers according to their sensitivity to voltage dips in critical areas is given. The main measures to prevent technical consequences of voltage dips are described. In order to ensure predictable operation of protection systems, it is necessary to analyse and prepare measures to improve power quality. To this end, high accuracy class recorders can be successfully used and measurements should be made at characteristic points of the network, power centres and at the common connection points of consumers. The consequences of voltage dips have been allocated to economic damage at companies. Without a general account of the damage caused by poor power quality, it is not possible to correctly calculate the economic effect of improving the reliability of technical systems, both in design and in operation. Therefore, it is proposed to use contextual factors of energy efficiency. Hence, an approach to the selection of surge protection measures is derived which requires consideration of the cost-benefit test of the technical measures. Thus, in order to select any of the surge protection measures, it is first necessary to analyse the statistical data, to understand the cause of the equipment outage and then to make a technically and economically sound decision to improve the reliability of the electricity supply. It is possible that the simplest and most effective solution for surge protection may not be in the electrical part but in the process or instrumentation system.

Automated metering and power quality systems in power supply systems

The article shows that the data of the collected by the automated commercial electricity metering systems are an ensemble of daily realizations of random processes of power consumption of the power supply system. The main purpose of using automated systems of commercial and technical electricity metering is to reduce power consumption. But it is noted that the efficiency of using data of the automated commercial electricity metering system, efficiency and proper management of energy consumption depends on the operators of automated workstations. Considering the rapid improvement of both technical means and mathematical methods that can be applied to address energy efficiency issues, there is a need to transform remote data collection systems from electricity meters, taking into account quality, into a measuring and information structure capable of not only collecting data from meters, electrical energy, but also analyse them. The main method for detecting undercounts is given - the balance method. On the basis of the balance method, it is proposed to automatically calculate the unbalance for each section of the 6, 10 or 110 kV line of the main step-down substations and distribution points, taking into account the number and accuracy classes of commercial metering and technical metering devices. It is proposed to balance the load on the results of calculations performed by automated commercial electricity metering system in order to reduce energy losses and reduce payment for electricity. It is proposed in the work that the automated commercial electricity metering system should calculate the coefficients of form, maximum, load, as well as other morphometric characteristics of the graphs of electrical loads. The work drew attention to a number of problems arising in the calculation of these parameters: electronic meters measure the data necessary for calculations but not with the specified discreteness and, most importantly, their measurement of these parameters of the quality of electrical energy is not metrologically certified, therefore, such data can only be relied on as background information.

Mapping of crop types and crop sequences with combined time series of Sentinel-1, Sentinel-2 and Landsat 8 data for Germany

Monitoring agricultural systems becomes increasingly important in the context of global challenges like climate change, biodiversity loss, population growth, and the rising demand for agricultural products. High-resolution, national-scale maps of agricultural land are needed to develop strategies for future sustainable agriculture. However, the characterization of agricultural land cover over large areas and for multiple years remains challenging due to the locally diverse and temporally variable characteristics of cultivated land. We here propose a workflow for generating national agricultural land cover maps on a yearly basis that accounts for varying environmental conditions. We tested the approach by mapping 24 agricultural land cover classes in Germany for the three years 2017, 2018, and 2019, in which the meteorological conditions strongly differed. We used a random forest classifier and dense time series data from Sentinel-2 and Landsat 8 in combination with monthly Sentinel-1 composites and environmental data and evaluated the relative importance of optical, radar, and environmental data.Our results show high overall accuracy and plausible class accuracies for the most dominant crop types across different years despite the strong inter-annual meteorological variability and the presence of drought and non-drought years. The maps show high spatial consistency and good delineation of field parcels. Combining optical, SAR, and environmental data increased overall accuracies by 6% to 10% compared to single sensor approaches, in which optical data outperformed SAR. Overall accuracy ranged between 78% and 80%, and the mapped areas aligned well with agricultural statistics at the regional and national level. Based on the multi-year dataset we mapped major crop sequences of cereals and leaf crops. Most crop sequences were dominated by winter cereals followed by summer cereals. Monocultures of summer cereals were mainly revealed in the Northwest of Germany. We showcased that high spatial and thematic detail in combination with annual mapping will stimulate research on crop cycles and studies to assess the impact of environmental policies on management decisions. Our results demonstrate the capabilities of integrated optical time series and SAR data in combination with variables describing local and seasonal environmental conditions for annual large-area crop type mapping.

Експериментальне визначення стану текстильних матеріалів десантної парашутної системи Д-5 серії 2 після тривалого зберігання. Повідомлення 2. Статистичні характеристики результатів вимірювання показників строп основного парашуту

The subject of the article is the analysis of the array of experimental data of loading and elongation at break of the slings of the main parachute landing parachute systems D-5 series 2 1973 and 1974 years of manufacture after long-term storage with zero (inexhaustible) resource. The current article attempts to determine the ratio of external factors related to the natural factors of aging of polymers, and internal, due to errors in the measurement process, based on statistical analysis of measurement results. Objective: to determine the degree of influence of internal and external factors on the process and result of measuring indicators. The following methods and equipment were used. An improved method of spot sampling of the samples under study of landing parachute systems D-5 series 2 for laboratory studies to determine the load at break and elongation at break of the slings of the main parachute. Measurements were performed on a machine of bursting brand ИР 5047-50M2C, accuracy class - 0.5 for the measurement range from 0.5 kN to 5 kN. The volume of the party was 25 parachute systems, only 250 elementary tests. The array of empirical data was processed by mathematical and statistical methods of the software package Descriptive statistics on the add-on of MS EXCEL Analysis Package. The following results were obtained. The relative error of the results of load measurement when breaking the slings of the domes of parachutes of 1973 production was ± 5.0%, for parachutes of 1974 production - ± 3.8%. The relative error of the results of measuring the elongation at the break of the slings of the domes of parachutes of 1973 manufacture was ± 2.9%, for parachutes of 1974 manufacture ± 3.3%. Given that the measuring instrument has an error of ± 0.29% in the passport, which can be considered systematic, the overall level of uncertainty is acceptable for conventional measurements in engineering. Conclusions. The main factors of accidental errors in the process of measuring the load at break and elongation at break of the slings of the main parachute are external factors due to the state of the cord structure and changes in the internal structure of the polymer.

Dimensional Accuracy and Surface Quality of AZ91D Magnesium Alloy Components after Precision Milling.

This study investigates a precision milling process conducted with the use of conventional end mills and a standard CNC (Computer Numerical Control) machine tool. Milling tests were performed on samples of AZ91D magnesium alloy using TiB2- and TiAlN-coated three-edge end mills measuring 16 mm in diameter. The following technological parameters were made variable: cutting speed, feed per tooth and axial depth of cut. The effects of precision milling were evaluated by analysing the scatter of dimension values obtained in successive tool passes. In addition to that, deviations from the assumed nominal depth as well as obtained ranges of dimension varation were analysed. The study also examined surface quality obtained in the precision milling process, based on the basic surface roughness parameters: Ra, Rz and RSm. Results have confirmed that the use of conventional cutting tools and a standard CNC machine tool makes it possible to manufacture components characterized by relatively small scatter of dimension values and high accuracy classes. Additionally, the results have shown that the type of tool coating and variations of individual technological parameters exert impact on the dimensional accuracy and surface quality obtained.

The use of machine learning for inverse uncertainty quantification in TRACE code based on Marviken experiment

Inverse Uncertainty Quantification (IUQ) methods are gaining recognition in the application of Best Estimate Plus Uncertainty methodologies. Typically, the code input parameters constituted the sources of uncertainties that cannot be estimated other than by user expertise. The IUQ methods aim at providing a more robust and scientific estimation of the distributions of those parameters. In this paper, an approach has been proposed to use machine learning to quantify the uncertainty of critical flow parameters available in the TRACE code.Serving as the means to the ultimate goal of IUQ, the machine learning algorithm has also been utilized in the qualitative assessment of discrepancies between the experiment and calculations. First, a set of Monte Carlo calculations were performed for selected Marviken Critical Flow Tests with permutated values of input parameters of TRACE code. Then, utilizing a supervised machine learning model and a set of features describing the mass flow progression, a Random Forest classifier was used to assign the results to one of the defined classes of prediction accuracy. This analysis has been done using two different training datasets to present the influence of the training data selection on the classification.The machine learning classification resulted in creating a class for which the results with the best fit to the experiment were collected. Derivation of this class created an opportunity to propose ranges and probability distribution functions for CHM12 and CHM22 TRACE internal variables, which is a goal for IUQ methods. Lognormal distribution has been proposed for CHM12 with a mode equal to 0.87, while normal distribution was proposed for CHM22 with a mean equal to 0.9. Variables C1RC2 and C2RC2 proved to be uninfluential on the results. The PDFs for CHM12 and CHM22 have been verified on all 26 Marviken tests. The article proposes a method that can be used in best-estimate analyses to obtain reliable distributions of input variables.

Algorithm for determining the unbalances of continuous mixers rotors

The paper presents a design model of a continuous mixer, which employs working shafts with kneading and scraping blades as the equivalent rotors. The rotors are represented in the orthogonal system x, y, z. An algorithm for reducing a three-dimensional system to flat ones using three-dimensional simulation is proposed to simplify further calculations. The inertia and the mass moments of the rotors’ structural elements were determined for the specific parameters of the parts obtained by blanks casting taking into account the accuracy classes. The conducted research allowed developing recommendations for choosing rational methods for manufacturing parts of continuous mixers and optimal parameters for the operation of the mixer.

Using a balanced scorecard to identify opportunities to improve code review effectiveness: an industrial experience report

Peer code review is a widely adopted software engineering practice to ensure code quality and ensure software reliability in both the commercial and open-source software projects. Due to the large effort overhead associated with practicing code reviews, project managers often wonder, if their code reviews are effective and if there are improvement opportunities in that respect. Since project managers at Samsung Research Bangladesh (SRBD) were also intrigued by these questions, this research developed, deployed, and evaluated a production-ready solution using the Balanced SCorecard (BSC) strategy that SRBD managers can use in their day-to-day management to monitor individual developer’s, a particular project’s or the entire organization’s code review effectiveness. Following the four-step framework of the BSC strategy, we– 1) defined the operation goals of this research, 2) defined a set of metrics to measure the effectiveness of code reviews, 3) developed an automated mechanism to measure those metrics, and 4) developed and evaluated a monitoring application to inform the key stakeholders. Our automated model to identify useful code reviews achieves 7.88% and 14.39% improvement in terms of accuracy and minority class F1 score respectively over the models proposed in prior studies. It also outperforms human evaluators from SRBD, that the model replaces, by a margin of 25.32% and 23.84% respectively in terms of accuracy and minority class F1 score. In our post-deployment survey, SRBD developers and managers indicated that they found our solution as useful and it provided them with important insights to help their decision makings.

Post-Market Surveillance of a Blood Glucose Test Strip Demonstrates No Evidence of Interference on Clinical Accuracy in a Large Cohort of People with Type 1 or Type 2 Diabetes.

Regulations and industry guidance relating to testing for interference in blood glucose monitoring (BGM) systems continue to focus on in vitro laboratory bench tests. Post-market surveillance (PMS) in a clinical setting allows for BGM accuracy assessments to evaluate the impact of real-world exposure to polypharmacy in people with diabetes. This study evaluated the OneTouch Select Plus® BGM test-strip accuracy with respect to polypharmacy using a clinical registry dataset. Medication profiles were analysed for 1023 subjects (425 with type 1 (T1D) and 598 with type 2 diabetes (T2D)) attending 3 UK hospitals. Blood samples were analysed to determine clinical accuracy of the BGM test-strip against a laboratory comparator. 538 different medications (48 diabetes and 490 non-diabetes) were recorded across the 1023 subjects. Patients took on average 6.9 (n = 1-36) individual medications and 4.1 (n = 1-13) unique medication classes. Clinical accuracy to EN ISO 15197:2015 criteria were met irrespective of increasing average number of individual medications, categorized from 1-3, 4-6, 7-9, 10-12 and >12 taken per subject (97.7%, 97.7%, 97.8%, 97.8%, and 98.4%, respectively). Clinical accuracy criteria were met across 15 classes of medication using the combined dataset (97.9%; 29784/30433). Surveillance Error Grid (SEG) analysis showed 98.7% (29959/30368) of readings presented no clinical risk. No individual class or combination of medication classes impacted clinical accuracy of the BGM test-strip. Clinical performance for the test strip under assessment demonstrated no evidence of interference from over 500 prescription medications, with clinical accuracy maintained across a range of polypharmacy conditions in people with diabetes.

Джерело живлення вимірювальних датчиків при виконанні експериментальних досліджень електротепломеханічної системи

The main part of scientific research is the results of the experiment, because they make it possible to establish the existing dependencies of the course of processes on a real object, confirm theoretical calculations and a mathematical model of an electrothermal-mechanical system. The work is devoted to the issue of experimental research of power supplies for measuring and recording equipment. According to the purpose, a technique was proposed by which experimental studies of the presence of pulses, noise and fluctuations in the output voltage of pulse and transformer power supplies were carried out. The influence of the deviation of the output voltage on the fluctuations of the voltage readings on the measuring and recording equipment has been investigated. Based on the results of experimental studies of power supplies, the proposed technique can be taken as a basis for selecting power supplies in accordance with the requirements for the required accuracy of reading indicators from the measuring equipment in accordance with their accuracy class, within the total error permissible for this type of experiment. A power source for measuring and recording equipment was selected for experimental studies of an electrothermal-mechanical system to intensify the process of methane formation in a biogas reactor in order to determine as accurately as possible the energy costs for biogas production, due to the fact that the process of producing biogas is long, therefore, a large error in determining energy costs affects an increase in actual energy costs in production in relation to the calculated and experimental data. The practical value of the work lies in the fact that the use of power supplies with a lower ripple of the output voltage in experiments will reduce the processing time of the obtained data arrays, increase the efficiency of the experiment and the accuracy of the revealed dependencies. The methodology presented in the work also makes it possible to more efficiently use financial resources for the purchase of devices in the preparation and conduct of scientific and experimental research. Keywords: power supply, voltage pulse, accuracy, scientific research, experiment, PeakTech

Use of High Performance Liquid Chromatography in the Analysis of a New Substance VMA-10-18

Introduction. Quinazoline derivatives have a wide range of pharmacological properties, which makes this group quite unique among other classes of heterocyclic compounds. Substance VMA-10-18, which has cerebrovasodilating, antidepressant, anxiolytic and nootropic properties, may become a promising new drug. In this regard, an urgent task is to develop methods for standardizing this substance.Aim. Development of a method for the quantitation of related impurities of a new biologically active substance VMA-10-18 (Quinazophene) by HPLC with subsequent statistical processing of the results.Materials and methods. To develop the conditions for chromatographic analysis, was used a highly purified substance 3-[2-(4-methoxyphenylamino)-2-oxoethyl]-quinazolin-4(3H)-one, as well as its related impurities: impurity I (unsubstituted quinazolin-4(3H)-one) and impurity II (4-methoxychloroacetanilide). Test solutions were prepared using volumetric glassware of accuracy class 1. Ethyl alcohol 95 % was used as a solvent. Chromatography was performed using a Dionex UltiMate 3000 system (Dionex, United States) with a spectrophotometric detector. The analysis was carried out at a wavelength of 231 nm. Data collection and processing was carried out using the Chromeleon v.7 system. A mixture of acetonitrile and orthophosphoric acid was used as a mobile phase. The analysis was performed in an isocratic mode. The validation of the developed method was carried out taking into account the requirements of the State Pharmacopeia of Russian Federation XIV edition and the recommendations of the ICH.Results and discussion. The optimal conditions for chromatography of the VMA-10-18 substance and its impurities have been developed. It was found that for a clear separation of the peaks of the substance and impurities among themselves, the mobile phase should contain acetonitrile and orthophosphoric acid in a ratio of 80 : 20. The specificity of the method was determined by chromatography of ethyl alcohol in order to exclude its influence on the analysis results. The linearity and correctness of the method were determined at 7 levels of concentration of impurities of the substance. The correlation coefficient has exceeded 0.99. Also, the free term of the linear dependence equation (a) for both impurities was less than its confidence interval (Δа), which proves the absence of a systematic error of the method. When determining the "Convergence" indicator, the calculated relative standard deviation did not exceed 2 %. When determining the intralaboratory precision, Student's t-test and Fisher's F-test were calculated. Both indicators met the stated requirements.Conclusion. A method for the quantitative determination of impurities in the VMA-10-18 substance by HPLC has been developed and validated.

Mechatronic Control Devices for a Modern Ship’s Magnetic Compass

One of the disadvantages of existing main magnetic compasses (МС) is the presence in their readings of an error from pitching due to the influence of centripetal and tangential accelerations when the MC is placed at a certain distance from the center rocking of the ship. This error can be unacceptably large, especially when using the compass in high latitude environments. This effect can be compensated by using a gyroscopic angular rate sensor (ARS), which measures the angular yaw rate of the ship. The work is devoted to the results of research and simulation of two correction system, which is introduced into the measuring circuit of the MC. Each of the correction systems presented in this work can be considered as mechatronic control device for a modern MC, one of them is positional, and the other is according to the angular yaw rate of the ship. The paper shows the advantages and disadvantages each of systems. So, a feature of the positional correction system is the need to use ARS of a tactical accuracy class (for example, a fiber-optic gyroscope). At the same time, the yaw rate correction system makes it possible to use a cheap micromechanical gyroscope (MMG). Despite the use ARS of various accuracy classes, both proposed correction systems allow achieving similar results, which leads to an obvious conclusion about the advisability of using the correction system with MMG, which allows to significantly reduce the cost of the MC, as well as to reduce its weight and dimensions.

Path Loss Measurement Validation Using Naïve Bayes Classification for High-Speed Rail

This work proposes path loss measurement validation for high-speed rail wireless communication using Naïve Bayes Classification Method. Path loss propagation model is a major component in wireless network planning in order to meet expected service level requirements and optimized cell towers distribution. However, path loss in high-speed rail propagates rapidly because of unexpected environmental shifts, high mobility, and unique channel modelling. All these unique characteristics lead to inaccuracies and uncertainties in the path loss measurement. Naïve Bayes Classification with Gaussian Classifier offers a better solution in validating path loss measurement than the conventional method for typical wireless communication, which provides statistical descriptions of site-specific environments. The measurement dataset has been taken as continuous values and it is assumed to be distributed according to normal distribution. The dataset has been collected from a running high-speed train. Data discretization has been used as a pre-processing step of transforming continuous data attribute values into a finite set of intervals consisting of path loss in maximum and minimum speed for accuracy or inaccuracy class. The satisfying result of the best performance has been obtained in Accuracy Value (0.9114), Precision Value (0.9147), Recall Value (0.8772), F1-score (0.8956), and Area Under Curve score (0.83). The results have shown that the Naive Bayes method can potentially replace the conventional method in validating path loss measurement, especially for high-speed rail.

Typical Errors, Accuracy Classes and Currently Expected Accuracy of Inertial Measurement Units

Inertial measurement units can nowadays be found in a wide range of applications, from consumer electronics to precision surveying systems requiring high accuracy. IMUs are also widely used in aviation, especially for UAVs. The gyroscopes and accelerometers in IMUs have specific operating modes that would result in specific errors typical of such instruments. This paper reviews the typical errors of IMUs and the accuracy that can be achieved with these instruments today in each application area.

Why Should We Test the Wideband Transformation Accuracy of Medium Voltage Inductive Voltage Transformers?

In this paper the results of the tests of the wideband transformation accuracy of medium voltage (MV) inductive voltage transformers (VTs) in the frequencies range from 50 Hz up to 5 kHz are presented. The values of voltage error and phase displacement for transformation of the harmonics of distorted primary voltages are determined. In the case of a typical 50 Hz-type inductive VT with a rated primary voltage equal to (15/√3) kV and (20/√3) kV manufactured by an international company the limiting values of the accuracy classes extension for quality metering required by the standard IEC 61869-6 for the Low Power Instrument Transformers (LPIT) were not exceeded. While, in the same test other MV inductive VTs show poor accuracy and even resonance at multiple frequencies. Unfortunately, this problem also arises from nonlinearity of the magnetization characteristic of their magnetic core. Therefore, for transformation of the sinusoidal voltage in the secondary voltage significant but not easily detectable values of the low order higher harmonics are present. Moreover, for transformation of harmonics of distorted primary voltage the influence of connected capacitance on the obtained values of voltage error and phase displacement was tested.

DETERMINATION OF THE COMPRESSIVE STRESS OF A RAIL USING THE EFFECT OF ACOUSTOELASTICITY AND STRAIN GAUGE

A method for monitoring the compression stress in a rail and a sample made of steel 20 using the effect of acoustoelasticity and strain gauge has been developed. Wire load cells were pasted to the opposite sides of the rail and the sample. Measurements, recording and processing of strain gauge information was carried out by a certified microprocessor strain gauge system MMTS-64.01 with accuracy class 0.2. To control the compression stress, the developed microprocessor-based ultrasonic system “Akusto-1” was used, which operates on the basis of the acoustoelasticity effect. The angle of input of ultrasonic vibrations, equal to 18°. This allowed to excite longitudinal, transverse and transformed waves in the object. Compressive stresses in the rail and steel sample were carried out by 250-ton loading machine “PSY-250”. Longitudinal and transformed ultrasonic waves were used to control compressive stresses. A comparative analysis of the experimental and calculated dependences of compressive stresses on the load obtained by acoustic, tensometric and computational methods is performed. The reliability of the experimental and calculated results was controlled by a certified microprocessor strain gauge system MMTS-64.01.

Penerapan Data Mining Untuk Memprediksi Daya Serap Lulusan Siswa Menggunakan Algoritma Native Bayes

The importance of predicting the absorption of Vocational High School (SMK) graduates in the world of work, especially SMK Negeri 9 Muaro Jambi which is not yet known about the prediction of the world of work that accepts SMK graduates so that the purpose of this study is to analyze the prediction of the accuracy of the absorption of graduates of SMK Negeri 9 Muaro Jambi as material. a reference to see whether the graduates of SMK Negeri 9 Muaro Jambi have achieved the expected goals or not so that this analysis can be used as input for schools to improve the competence of SMK students. This implementation is assisted by using the Rapidminer and WEKA applications with 100 alumni work data input. The attributes used in this analysis process are Department, Waiting Time and Field of Work and Class of Work Field Accuracy. The process in this analysis is carried out with data that has been provided with the Naïve Bayes Classification Method to predict the absorption of graduates. The results of this study the highest accuracy value in the Rapidminer application is at 100% and WEKA is at 100%.

New design of the evolvent worm mill with carbide turning rack

For high-speed cutting of teeth of cylindrical wheels made of structural and difficult-to-machine steels and alloys, cast iron, non-ferrous metals and various non-metallic materials with increased abrasive ability in conditions of mass and large-scale production, carbide hob cutters are used. A promising direction for hob cutters is the use of rotary racks as cutting elements. However, when they are rotated by 180°, errors in the tool profile are transferred to the workpiece. Therefore, the existing designs of such cutters are used only for roughing or semi-finishing, reaching accuracy classes B, C and D according to GOST 9324-2015. In order to improve their accuracy, the article proposes a new design of the assembled hob cutter with carbide rails, which allows maintaining the required tooth profile after turning the cutting elements. Milling cutters with flat front surfaces and back surfaces are adopted, the generatrix of which is perpendicular to the cutting edge. From the point of view of the working conditions of the cutting tool, studies of the kinematic angles were carried out. The calculation was carried out according to the formulas derived according to the scheme for the general option of cutting the wheel with a worm cutter. In this case, the working angles were calculated at points on the tooth profile at different moments of rotation of the cutter and along the entire length of the cutter. The analysis of the influence of the main parameters of the cutter on the cutting angles is presented. The possibility of using the design of a prefabricated worm cutter with flat front surfaces and back surfaces, the generatrix of which is perpendicular to the cutting edge, has been confirmed. Recommendations for achieving optimal working angles in the process of gear hobbing for milling cutters of the adopted design are proposed.

Relationship between the characteristics of machine parts and parameters of technological equipment

The aspects of the substantion of the selection of parametera of CNC metal-cutting machines are considered on the basis of their relationship with the technical characteristics of the manufactured machine parts that make up the regional data bank. A new approach to grouping parts using cluster analysis is proposed. For the processing of eight groups of parts in the form of bodies of revolution, the parameters of machine tools are substantiated (the number and composition of shape forming coordinates, the size of the working space, the structure of technological operations, the accuracy class according to GOST 8-82E, as well as the accuracy and roughness of the processed surfaces obtained depending on workpiece material. Keywords: machine tool, numerical control, part, shape forming coordinate, workspace. v.epifanov73@mail.ru

The principle of creating a "smart" electricity meter in electric traction networks with stochastic electromagnetic processes

Voltage and current are sharply variable random (stochastic) processes in traction networks of DC electric transport systems. As a result, electronic and hybrid electricity meters used in electric systems measure electric power with a large relative error that significantly exceeds that of their accuracy class. In this paper the principle of developing smart meters for accounting the electricity transmitted from traction substations to electric rolling stock through a traction network is proposed. Proposed ideas are developed on the basis of the random processes correlation theory. The meter operates in real time and monitors not a set of realizations of random voltage and current processes, but their deterministic characteristics, that is, time functions of mathematical expectations and variances which make up the background of its operating principle. The experimental implementation of the proposed principle has been conducted in the feeder zone of an A-B section of the GisDnieper Railway of Ukraine, where registration and processing of realizations of stochastic voltage and current processes obtained in real operation mode has been done. The ratios obtained for active and reactive power can be applied not only for traction power grids, but also for electric networks of external power supply of DC electric traction systems as the basis for the “smart meter” design.