Determining the static characteristic of a measuring current transformer at a reduced load of the metering unit

Authors

DOI:

https://doi.org/10.15587/1729-4061.2022.265068

Keywords:

current transformer, static characteristic, current error, reduced load, regression line

Abstract

The object of the research is a measuring current transformer of the electromagnetic type, which is used as part of the electricity metering unit. The current transformers functioning in the mode of reduced primary current is accompanied by significant errors. The existence of such a regime for a long time due to downtime of production equipment leads to a significant underestimation of electricity. This leads to unjustified financial losses for energy supply companies as electricity in many countries has become more expensive. The static characteristic of the measuring current transformer at a reduced load of the metering unit is described by a linear statistical model. The parameters of the model are estimated on the basis of empirical data using methods of covariance analysis. The adequacy of the model is confirmed by analysis of regression residuals. The obtained statistical model of the static characteristic, unlike the known ones, is characterized by universality, as it describes current transformers with an arbitrary transformation ratio within the studied accuracy class of 0.5S. The uncertainty of the current error is estimated using the prediction intervals for the transformers secondary currents as a function of the primary currents, calculated on the basis of the obtained model. The prediction intervals for sample values of the current error were obtained through the application of the proposed approach for uncertainty estimation of such an error at a reduced load of the metering unit. It was found that the current error can reach −20 %. Taking into account the indicated intervals for measuring current transformers at a reduced load of the metering unit during billing will allow energy supply companies to increase the accuracy of commercial electricity metering.

Author Biographies

Kateryna Vasylets, National Aviation University

Postgraduate Student

Department of Computerized Electrical Systems and Technologies

Volodymyr Kvasnikov, National Aviation University

Doctor of Technical Sciences, Professor, Head of Department, Merit Metrologist of Ukraine

Department of Computerized Electrical Systems and Technologies

Sviatoslav Vasylets, National University of Water and Environmental Engineering

Doctor of Technical Science, Professor

Department of Automation, Electrical Engineering and Computer-Integrated Technologies

References

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Determining the static characteristic of a measuring current transformer at a reduced load of the metering unit

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Published

2022-10-30

How to Cite

Vasylets, K., Kvasnikov, V., & Vasylets, S. (2022). Determining the static characteristic of a measuring current transformer at a reduced load of the metering unit . Eastern-European Journal of Enterprise Technologies, 5(8(119), 13–20. https://doi.org/10.15587/1729-4061.2022.265068

Issue

Vol. 5 No. 8(119) (2022): Energy-saving technologies and equipment

Section

Energy-saving technologies and equipment

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Copyright (c) 2022 Kateryna Vasylets, Volodymyr Kvasnikov, Sviatoslav Vasylets

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