scholarly journals Metrological characterisation of current transformers calibration unit for accurate measurement

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 6
Author(s):  
Valentyn Isaiev ◽  
Oleh Velychko
Keyword(s):  
Measurement Uncertainty ◽  
Current Phase ◽  
Measuring Instruments ◽  
Current Transformers ◽  
Sources Of Uncertainty ◽  
Ratio Error ◽  
Phase Displacement ◽  
Measurement Results ◽  
The Difference ◽  
Detailed Presentation

<p class="Abstract"><span lang="EN-US">The manuscript presents a method for the metrological characterisation of the commercial AC comparators used to calibrate current transformers. The theoretical basis for simulating the difference between two almost identical currents has been outlined, as well as the mathematical models for both a ratio error and a phase displacement has been derived. The measurement setup, consisting of conventional measuring instruments, has been described with a detailed presentation of its parameters. The sources of uncertainty have been distinguished and analysed with determining the current phase shift which led to a significant increase of relative measurement uncertainty. The simulation of measurement results was yielded in two ways: physically using a method presented and virtually using a Monte Carlo method. The second method confirmed that evaluating the measurement uncertainty through derived sensitivity coefficients is correct enough. The simulation results in the range from 1 to 1200 parts per million for both ratio error and phase displacement motivated the use of a comparator characterised through the proposed method for accurate measurement, especially for very low errors.</span></p>

Measurement of Ratio Error and Phase Displacement of DC Tolerant Current Transformers

2007 ◽  
Vol 5 (1) ◽  
pp. 289-292 ◽  
Author(s):  
Pavel Mlejnek ◽  
Petr Kašpar ◽  
Karel Draxler
Keyword(s):  
Current Transformers ◽  
Ratio Error ◽  
Phase Displacement

scholarly journals Measuring the Voltage Dependence of Current Transformers

2020 ◽  
Author(s):  
Helko van den Brom ◽  
Ronald van Leeuwen ◽  
Gert Rietveld ◽  
Dennis Hoogenboom
Keyword(s):  
Leakage Current ◽  
High Voltage ◽  
Voltage Dependence ◽  
Current Transformers ◽  
Ratio Error ◽  
Phase Displacement ◽  
Hv Cable

A setup has been developed to determine the voltage dependence of the ratio error and phase displacement of current transformers (CTs) used for medium- or high-voltage (HV) applications. A shielded HV cable is used to protect the reference CT for the voltage applied to the CT under test. As a first step, a method was developed to determine and correct for the effect of the leakage current through this cable on the ratio error and phase displacement of the reference CT for voltages up to 24 kV.

Comparison between bottom-up and top-down approaches in the estimation of measurement uncertainty

2015 ◽  
Vol 53 (7) ◽  
Author(s):  
Jun Hyung Lee ◽  
Jee-Hye Choi ◽  
Jae Saeng Youn ◽  
Young Joo Cha ◽  
Woonheung Song ◽  
...  
Keyword(s):  
Measurement Uncertainty ◽  
Uncertainty Budget ◽  
Internal Quality ◽  
Systematic Bias ◽  
Top Down ◽  
Bottom Up ◽  
Sources Of Uncertainty ◽  
Clinical Laboratories ◽  
Measurement Results ◽  
Low Glucose

AbstractMeasurement uncertainty is a metrological concept to quantify the variability of measurement results. There are two approaches to estimate measurement uncertainty. In this study, we sought to provide practical and detailed examples of the two approaches and compare the bottom-up and top-down approaches to estimating measurement uncertainty.We estimated measurement uncertainty of the concentration of glucose according to CLSI EP29-A guideline. Two different approaches were used. First, we performed a bottom-up approach. We identified the sources of uncertainty and made an uncertainty budget and assessed the measurement functions. We determined the uncertainties of each element and combined them. Second, we performed a top-down approach using internal quality control (IQC) data for 6 months. Then, we estimated and corrected systematic bias using certified reference material of glucose (NIST SRM 965b).The expanded uncertainties at the low glucose concentration (5.57 mmol/L) by the bottom-up approach and top-down approaches were ±0.18 mmol/L and ±0.17 mmol/L, respectively (allWe presented practical and detailed examples for estimating measurement uncertainty by the two approaches. The uncertainties by the bottom-up approach were quite similar to those by the top-down approach. Thus, we demonstrated that the two approaches were approximately equivalent and interchangeable and concluded that clinical laboratories could determine measurement uncertainty by the simpler top-down approach.

scholarly journals Evaluation of measurement uncertainty of impact resistance of ceramic brick

2020 ◽  
Vol 185 ◽  
pp. 04040
Author(s):  
Chen Weizhe
Keyword(s):  
Measurement Uncertainty ◽  
Ceramic Tile ◽  
Impact Resistance ◽  
Final Conclusion ◽  
Test Results ◽  
Ceramic Brick ◽  
Sources Of Uncertainty ◽  
Related Data ◽  
Measurement Results

As the economy continues to grow rapidly, people's requirements for product quality are increasing year by year, including ceramic tile products, which, as a typical building material product, are widely used in various large and small buildings. The quality of ceramic tile products is mainly evaluated through inspection and testing. As an important part of the test results, measurement uncertainty is an important parameter that characterizes the reliability of the measurement results. This article analyzes the sources of uncertainty in the measurement of ceramic tile impact resistance, uses the measurement results and related data, and draws the final conclusion.

Uncertainty Analysis for Fiber Permeability Measurement

2005 ◽  
Vol 127 (4) ◽  
pp. 907-911 ◽  
Author(s):  
Chensong Dong
Keyword(s):  
Measurement Uncertainty ◽  
Uncertainty Propagation ◽  
Permeability Measurement ◽  
Parameter Uncertainties ◽  
Factors Affecting ◽  
Sources Of Uncertainty ◽  
Measurement Results ◽  
Simulation Results ◽  
Instrument Accuracy ◽  
Significant Factors

An uncertainty study for fiber permeability measurement is presented in this paper. The sources of uncertainty were identified. This paper focuses on the instrument and environmental uncertainties. The parameter uncertainties of both unsaturated and saturated measurements were estimated based on instrument accuracy limitations and environmental influences. Their influences on the permeability uncertainty were investigated by uncertainty propagation and Monte Carlo simulation. The significant factors affecting the permeability measurement uncertainty were identified. The results show that (1) unsaturated measurement has a higher accuracy than saturated measurement; (2) the significant factors affecting measurement results are pressure and viscosity. Based on the simulation results, the approaches to reduce measurement uncertainty were proposed.

scholarly journals Measuring the Voltage Dependence of Current Transformers

2020 ◽  
Author(s):  
Helko van den Brom ◽  
Ronald van Leeuwen ◽  
Gert Rietveld ◽  
Dennis Hoogenboom
Keyword(s):  
Leakage Current ◽  
High Voltage ◽  
Voltage Dependence ◽  
Current Transformers ◽  
Ratio Error ◽  
Phase Displacement ◽  
Hv Cable

A setup has been developed to determine the voltage dependence of the ratio error and phase displacement of current transformers (CTs) used for medium- or high-voltage (HV) applications. A shielded HV cable is used to protect the reference CT for the voltage applied to the CT under test. As a first step, a method was developed to determine and correct for the effect of the leakage current through this cable on the ratio error and phase displacement of the reference CT for voltages up to 24 kV.

scholarly journals Investigations on the Optical Properties of InGaN/GaN Multiple Quantum Wells with Varying GaN Cap Layer Thickness

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Xiaowei Wang ◽  
Feng Liang ◽  
Degang Zhao ◽  
Zongshun Liu ◽  
Jianjun Zhu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Layer Thickness ◽  
Stark Effect ◽  
Chemical Vapor ◽  
Multiple Quantum ◽  
Three Samples ◽  
Measurement Results ◽  
Cap Layer ◽  
The Difference

Abstract Three InGaN/GaN MQWs samples with varying GaN cap layer thickness were grown by metalorganic chemical vapor deposition (MOCVD) to investigate the optical properties. We found that a thicker cap layer is more effective in preventing the evaporation of the In composition in the InGaN quantum well layer. Furthermore, the quantum-confined Stark effect (QCSE) is enhanced with increasing the thickness of GaN cap layer. In addition, compared with the electroluminescence measurement results, we focus on the difference of localization states and defects in three samples induced by various cap thickness to explain the anomalies in room temperature photoluminescence measurements. We found that too thin GaN cap layer will exacerbates the inhomogeneity of localization states in InGaN QW layer, and too thick GaN cap layer will generate more defects in GaN cap layer.

scholarly journals Optimised calibration programmes for comparators for instrument transformers

2021 ◽  
Vol 88 (2) ◽  
pp. 122-131
Author(s):  
Christian Mester
Keyword(s):  
Experimental Study ◽  
Operating Principle ◽  
Device Under Test ◽  
Operating Range ◽  
Ratio Error ◽  
Phase Displacement ◽  
Instrument Transformers ◽  
Instrument Transformer ◽  
Method Of Measurement

Abstract Traditionally, instrument transformers are calibrated using bridges. By definition, bridges use the null method of measurement. The traditional calibration programme for instrument transformer bridges characterise namely this null measurement. Many new commercial comparators for instrument transformer use a very different method. They sample the secondary signals of reference and device under test (dut) transformer independently. Based on the samples, magnitude and phase of both signals are determined. Ratio error and phase displacement are calculated. Consequently, the significance of their calibration using the traditional calibration programme is limited. Moreover, the operating range of modern comparators is much larger than that of bridges. The additional versatility cannot be used without an adapted calibration programme. This article analyses the calibration programmes for both technologies. An experimental study confirms both the suitability of the new calibration programme and the need to chose the calibration programme depending on the technology of the device to be calibrated. The conclusion is very general and applies to all measurement problems where an operating principle is replaced by another – when changing the operating principle, it is important to check the calibration programme and adapt it if necessary.

scholarly journals MODELING OF THE SPREAD OF MOTOR TRANSPORT NOISE IN ŠIAULIAI CITY / AUTOTRANSPORTO TRIUKŠMO SKLAIDOS ŠIAULIUOSE MODELIAVIMAS / МОДЕЛИРОВАНИЕ РАССЕЯНИЯ ТРАНСПОРТНОГО ШУМА В ГОРОДЕ ШЯУЛЯЙ

2011 ◽  
Vol 19 (1) ◽  
pp. 62-70 ◽  
Author(s):  
Leonas Paulauskas ◽  
Robertas Klimas
Keyword(s):  
Personal Computer ◽  
Noise Level ◽  
Negative Impact ◽  
Noise Measurement ◽  
Motor Transport ◽  
City Environment ◽  
Measurement Results ◽  
The Difference ◽  
Environment Noise ◽  
Level Detector

Rapidly growing urbanization causes the increase of noise level of various sources, that have a negative impact upon people's health. The contribution of noise caused by motor transport in city environment composes up to 80% of general impact of all the sources. The article presents the results of modeling of the spread of motor transport noise of Šiauliai city, maps of motor transport noise, recommendations for management of environment noise. MapNoise programme module, adapted to work in the ArcGIS Desktop 9.1 environment, was used for modeling motor transport noise. Noise measurement researches have been carried out using digital noise isolator Nor121, completed with digital level detector. NorXfar software was used to send the data to personal computer. Having evaluated the validity of modeling results it has been determined that the difference between the night noise modeling and measurement results does not exceed 2.2%, and varies from 0.5dB(A) to 1.1 dB(A). The obtained results indicate that 7.2% of the apartments of all city residents are influenced by the LDEN noise that exceeds the permitted noise level (LDEN >65 dB(A)) and 31.2% of the apartments of the residents are influenced by night noise that exceeds the permitted noise level (LN > 55 dB(A)). Santrauka Sparčiai vykstant urbanizacijos procesui, kinta įvairių šaltinių keliamo triukšmo lygis, didėja neigiama įtaka žmonių sveikatai. Miestų aplinkoje iki 80 % visuminio visų triukšmo šaltinių poveikio tenka autotransporto keliamam triukšmui.Straipsnyje pateikta autotransporto triukšmo sklaidos Šiauliuose modeliavimo rezultatai, autotransporto triukšmo žemėlapiai, aplinkos triukšmo valdymo rekomendacijos. Autotransporto triukšmui modeliuoti naudotas MapNoise programinismodulis, pritaikytas darbui ArcGIS Desktop 9.1 aplinkoje. Iš rezultatų matyti, kad 7,2% visų miesto gyventojų būstų yra veikiami paros triukšmo, viršijančio leidžiamąjį triukšmo lygį (LDVN > 65 dB(A)), ir 31,2% gyventojų būstų veikiami nakties triukšmo, viršijančio leidžiamąjį triukšmo lygį (LN > 55 dB(A)). Įvertinus modeliavimo rezultatų patikimumą nustatyta, kad paros ir nakties triukšmo modeliavimo ir matavimo rezultatų neatitiktis neviršija 2,2 % ir svyruoja nuo 0,5dB(A) iki 1,1dB(A). Резюме При быстром росте урбанизации увеличивается уровень шума, создаваемого разными источниками и отрицательно влияющего на здоровье населения. Шум от автотранспорта в городах составляет около 80% от всех источников шума. В статье представлены результаты моделирования рассеяния шума от автотранспорта в городеШяуляй, карты автотранспортного шума, рекомендации по управлению шумом в окружающей среде. Приизмерении шума был использован числовой анализатор шума № 121, укомплектованный с числовым детекторомуровня RMS. Для передачи данных в персональный компьютер использована программа NorXfer. Для моделирования автотранспортного шума использован программный модуль MapNoise, приспособленный дляработы в среде ArcGIS desktop 9.1. При анализе достоверности результатов моделирования было установлено, чтоих отличие от результатов измерения шума в течение суток и ночное время не превышает 2,2% и колеблется от0,5дБ(A) до 1,1дБ(A). Результаты исследования свидетельствуют о том, что 7,2% жилых помещений городаподвергаются суточному шуму, уровень которого превышает допустимый (LDVN > 65 дБ(A)) и 31,2% жилыхпомещенийгородаподвергаютсяшумувночноевремя,уровень которогопревышаетдопустимый (LN > 55дБ(A)).

Sign in / Sign up

Export Citation Format

Share Document