scholarly journals Use of statistical analysis methods in processing population survey data

2021 ◽  
pp. 58-60
Author(s):  
Vasilij Kalinchik ◽  
Vitaliy Pobigaylo ◽  
Vitaliy Kalinchyk ◽  
Daniil Filjanin
Keyword(s):  
Total Error ◽  
Current Transformer ◽  
Measuring Channel ◽  
Measuring Circuit ◽  
Metrological Characteristics ◽  
Measuring Instruments ◽  
Voltage Transformer ◽  
Current Transformers ◽  
Collection Device ◽  
Communication Lines

The article analyzes the structures of the measuring channels of electricity metering systems. It is shown that such a structure is determined by the types of measuring instruments used and the scheme of their connection, in particular, by the types of electricity meters installed at the metering points. Moreover, the counters can have a pulse or interface information output. It is shown that the path for measuring and metering electricity includes a measuring circuit consisting of measuring current and voltage transformers, an electricity meter, communication lines, a metering device and a data collection device. The applied method is based on the standardization of the metrological characteristics of individual elements of the measuring path and their synthesis based on the metrological characteristics of the entire electricity metering system. To calculate the total error of the measuring channel, a formula is used that takes into account only the errors of the measuring circuit. It is shown that in recent years there has been a tendency when measuring current transformers and, accordingly, electricity meters operate in the mode of low current loads. In this case, the errors of the elements of the measuring path are poorly studied. The graphs of errors of current transformers depending on load currents are given. It is shown that the values of the errors of current transformers vary with the magnitude of the load current and are in the region of negative values. Therefore, the wrong choice of current transformers can lead to a significant underestimation of electricity. The errors of voltage transformers depend mainly on the load on the secondary winding and do not significantly affect the total error. The resulting error of the measuring path current transformer - voltage transformer - electricity meter in the area of low loads is given. A change in errors in the area of low loads leads to serious metrological losses (underpayment of electricity). In the automation of electricity metering, graphs of changes in errors in the area of low loads are presented, which can serve as a basis for correcting the error of the measuring paths.

scholarly journals Research on lightning stroke model and characteristics of electronic transformer

2018 ◽  
Vol 160 ◽  
pp. 02007
Author(s):  
Mu Li ◽  
Lian Lian Li ◽  
Shu Bo Fang ◽  
Jing Jing Wang
Keyword(s):  
Current Transformer ◽  
Circuit Model ◽  
Transmission Characteristics ◽  
Voltage Transformer ◽  
Lightning Stroke ◽  
Current Transformers ◽  
Electronic Transformer ◽  
The Difference ◽  
Analysis Models ◽  
The Mathematical Model

In order to improve the reliability of power supply, a large number of electronic voltage and current transformers are used in digital substations. In this paper, the mathematical model of the electronic transformer is analyzed firstly, and its circuit model is given. According to the difference of working characteristics between voltage transformer and current transformer, the circuit model of voltage type electronic transformer and current type electronic transformer is given respectively. By analyzing their broadband transmission characteristics, the accuracy of the model is verified, and their lightning analysis models are obtained.

scholarly journals Reach and Operating Time Correction of Digital Distance Relay

2017 ◽  
Vol 7 (1) ◽  
pp. 58
Author(s):  
A N Sarwade ◽  
P K Katti ◽  
J G Ghodekar
Keyword(s):  
Low Voltage ◽  
Electrical Power ◽  
Operating Time ◽  
Current Transformer ◽  
Iron Core ◽  
Electrical Power System ◽  
Voltage Transformer ◽  
Distance Relay ◽  
Correct Operation ◽  
Secondary Current

Current and voltage signals recieved from conventional iron core Current Transformer (CT) and Voltage Transformer plays very important role for correct operation of Distance Distance Relay (DDR). Increase in secondary burden connected to CT causes it to saturate at earlier stage. The saturated CT produces distorted secondary current, causing DDR to under reach and to operate by certain time delay. Rogowski Coils (RCs) are attaining increased acceptance and use in electrical power system due to their inherent linearity, greater accuracy and wide operating current range. This paper presents use of RC as an advanced measurement device suitable for DDR. Case study for validation of use of RC is carried out on low voltage system. The simulation results of Distance protection scheme used for protection of part of 220kV AC system shows excellent performance of RC over CT under abnormal conditions.

Design and Analysis of PCB Rogowski Coil Current Transformer

2014 ◽  
Vol 672-674 ◽  
pp. 984-988
Author(s):  
Biao Su ◽  
Li Xue Li ◽  
Yi Hui Zheng ◽  
Xin Wang ◽  
Yan Liu ◽  
...  
Keyword(s):  
Power System ◽  
High Sensitivity ◽  
Current Transformer ◽  
Rogowski Coil ◽  
Electromagnetic Current ◽  
Current Transformers ◽  
Coil Current ◽  
Electronic Current ◽  
Rogowski Coils ◽  
Electronic Current Transformers

Electronic current transformers are more suitable for the development of power system compared with traditional electromagnetic current transformers. Rogowski coil current transformer is one of three electric current transformers. According to the measurement principle of Rogowski coils, the equivalent circuit of PCB Rogowski coils is analyzed. By using four PCB Rogowski coils combined, a PCB Rogowski coil current transformer is designed and tested. The results show that the designed PCB Rogowski coil transformer has good linearity and high sensitivity and measurement accuracy and it can meet the requirement of power system.

Determination of changes of metrological characteristics of measuring instruments with time

1978 ◽  
Vol 21 (2) ◽  
pp. 158-163
Author(s):  
I. V. Abuladze ◽  
A. I. Belyaevskii ◽  
A. A. Dzhevdet
Keyword(s):  
Metrological Characteristics ◽  
Measuring Instruments

Determination of precision conditions for measuring relative values in mechanical tests of various materials

2021 ◽  
pp. 9-17
Author(s):  
Svetlana Yu. Lohanina ◽  
Olga V. Baranova ◽  
Larisa V. Trubacheva
Keyword(s):  
Wear Resistance ◽  
Mechanical Testing ◽  
Mechanical Tests ◽  
Metrological Characteristics ◽  
Measuring Instruments ◽  
Quantitative Chemical Analysis ◽  
Uniformity Of Measurements ◽  
Multi Stage ◽  
Abrasive Disk ◽  
Accuracy Of Measurements

The problem of insufficient detail of the requirements for the developed and certified measurement methods used in mechanical testing of various materials is considered. The compatibility of the requirements of metrological support for the results of quantitative chemical analysis and indirect results of mechanical tests for the wear resistance of materials when rubbing against a fixed abrasive is relevant. To ensure the accuracy of measurements, it is proposed to use the grain size of the abrasive material and the rotation speed of the abrasive disk as variable factors. In order to establish the requirements for the metrological characteristics of materials during mechanical tests, in particular, when determining the relative wear resistance, the conditions for precision measurements are justified. The results of a multi-stage experiment-testing of materials for wear resistance with the use of various research and consumables, measuring instruments and testing equipment are presented. The conditions for the organization of the experiment in the case of determining other relative mechanical characteristics of the materials under study for establishing precision indicators in the development of methods of mechanical tests for abrasive wear are proposed and justified. The application of the obtained results will allow developers of mechanical testing methods to establish metrological characteristics of materials in compliance with all the requirements of the State System for Ensuring the Uniformity of Measurements of the Russian Federation.

Simulation Model for Assessing Operational Performance of Current Transformers

2007 ◽  
Vol 18-19 ◽  
pp. 71-77
Author(s):  
I. Sule
Keyword(s):  
Simulation Model ◽  
Current Transformer ◽  
Operational Performance ◽  
Current Transformers ◽  
Correct Operation ◽  
Operational Conditions ◽  
Secondary Current ◽  
Protection Scheme ◽  
The Core ◽  
Instrument Transformers

In determining the correct operation of relays of a protection scheme, proper representation of instrument transformers and their behavior in conditions where there can be saturation, is very critical. The main objective of this paper is to develop simulation model for assessing the operational performance of Current Transformer (CT). In order to test the validity of the developed model, three cases of CT operational conditions were considered, with data collected from Gombe, 330/132/33kV PHCN substation. The simulation results revealed various configuration performance responses that could affect relay protective schemes to different degrees. The CT responses revealed that the secondary current and voltage were distorted when the core flux linkages exceeded the set 9.2 pu saturation limit. It is concluded that the model developed for the CT of interest yield satisfactory results.

Estimate of total error of measuring instruments

1977 ◽  
Vol 20 (2) ◽  
pp. 182-183
Author(s):  
V. P. Petrov ◽  
Yu. V. Ryasnyi
Keyword(s):  
Total Error ◽  
Measuring Instruments

Error Calculating and Compensating Method of All-Optical Fiber Current Transformer in ± 10 kV DC Distribution Network

2019 ◽  
Vol 14 (11) ◽  
pp. 1606-1615
Author(s):  
Jicheng Yu ◽  
Changxi Yue ◽  
Jun Li ◽  
Dengyun Li ◽  
He Li
Keyword(s):  
Optical Fiber ◽  
Distribution Network ◽  
Current Transformer ◽  
Electromagnetic Current ◽  
Current Transformers ◽  
Wave Plate ◽  
Remote Transmission ◽  
Dc Distribution ◽  
All Optical ◽  
Database Technology

Current transformer is one of the main equipment in ±10 kV DC distribution network. Traditional electromagnetic current transformer has poor anti-jamming capacity and poor insulation, so it cannot realize transient protection. The emergence of all-optical fiber current transformer brings solutions to these problems, which has attracted more and more attention. In this study, aiming at the problem of error and compensation of λ/4 waveform of all-fiber current transformer, the fabrication method of λ/4 waveform is studied, the mathematical model of the waveform is established, the influence of the waveform error on the scale factor is analyzed, and a calculating device of angle difference and ratio difference to compare the error is designed. The device adopts the principle of traceability of quantities to collect the state data of the wave plate. At the same time, in order to collect data for errors, database technology and network technology are used to realize remote transmission of monitoring data. The error of the λ/4 wave plate is compensated, the bidirectional principle generated by the birefringence in the fiber ring is analyzed, and the data logic description of the transformer sensitive ring is performed. The phase delay and the angle of the shaft are selected as the main factors causing the error. Compensation is performed by means of peak segmentation and variable cancellation. In the experimental process, compared with the error sampling of the traditional transformer, the error calculated by the current amplitude and phase angle parameters obtained by the all-fiber current transformer is more accurate, and the compensation scheme can suppress the size of the birefringence and improve sensing accuracy of fiber optic current transformers. This study provides a powerful reference for the error analysis of all-fiber current transformer λ/4 wave plates, which is beneficial to promote the better application of such current transformers.

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