Error compensation method for current transformer

Wath, Manish Ganesh; Raut, Pankaj; Ballal, Makarand Sudhakar

doi:10.1109/icpeices.2016.7853244

Cited by 15 publications

(6 citation statements)

References 12 publications

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“…Many of the papers present solutions to correct the values of current or voltage errors and phase displacements of inductive CTs and VTs during their operation in distorted conditions [33,34,[44][45][46]. The majority of them concentrate on inductive voltage transformers (VTs), where the impact of the magnetic core's non-linear characteristics is less significant, resulting in a relatively low level of self-generated low-order higher harmonics in the secondary voltage.…”

Section: Error Correction Methodsmentioning

confidence: 99%

Challenges of Accurate Measurement of Distorted Current and Voltage in the Power Grid by Conventional Instrument Transformers

Kaczmarek

Stano

2023

Energies

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Power grids are a combined system where the electrical energy produced by the power plants is transmitted to consumers. This forms a specific interdependence where the recipients have a significant impact on the power quality. Therefore, the nonlinear loads connected by households and industrial customers cause current and voltage distortion in the power networks. This creates the need for accurate measurement of nonsinusoidal voltage and current composed not only from the fundamental component but also containing higher harmonics, interharmonics, and subharmonics. In order to ensure high transformation accuracy of distorted current and voltage, the inductive instrument transformers have to be tested in these conditions. Many papers describe their behavior during the transformation of sinusoidal current or voltage. Nowadays, the scientific field in this scope is focused on the evaluation of their exploitation properties for distorted signals. The common problem of inductive instrument transformers is the self-generation of low-order higher harmonics to the secondary current or voltage. In the case of the inductive VTs, an additional problem results from the resonance caused by the parasitic capacitance of the primary winding. The proposed solutions to compensate for the values of current or voltage errors and phase displacement of inductive instrument transformers are also analyzed.

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Section: Error Correction Methodsmentioning

confidence: 99%

Challenges of Accurate Measurement of Distorted Current and Voltage in the Power Grid by Conventional Instrument Transformers

Kaczmarek

Stano

2023

Energies

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“…Not only is the power factor of the load impedance unequal to one, but also the excitation reactance is not much larger than the excitation resistance. Thus, the phase displacement between İmN 1 and İ0 is not π/2 and is definitely not zero [15], and (8) is more reasonable than (9). Either (8) or (9) can be used to estimate the current error of CTs whose k N is equal to k C .…”

Section: Turns Ratio Equal To Current Ratio Causes Negative Current E...mentioning

confidence: 99%

Difficulties in producing CT caused by the current ratio regulation in IEC standard and suggestions of modification

Gan,

You,

Duan

et al. 2024

Meas. Sci. Technol.

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The integer current ratio requirements by standard IEC 61869-2 and users result in the numbers of current transformer (CT) winding turns being decimal, such as 5.94, 9.9, and 14.85. This makes the manufacturing of CTs complex, causing socioeconomic waste. It is pointed out in this paper that if the integer current ratio requirements can be changed to decimals, the number of CT winding turns may be made an integer, which makes it easy to produce low-error CTs. The error refers to the difference between the actual current ratio and the required current ratio for CTs. Additionally, if this change is made, iron core materials do not need to have high permeability. Furthermore, it is better to allow the manufacturers to mark freely the current ratio within a certain range on CT rating plates. The measure of changing the current ratio requirements or changing the way of marking the ratio on rating plates can significantly reduce the manufacturing difficulties and costs of CTs.

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“…There is also a proposal to use correction factors [14]. In addition, the control signal can provide compensation for the constant component of the measured current [15].…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

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

Vasylets

Kvasnikov

Vasylets

2022

EEJET

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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.

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Error compensation method for current transformer

Cited by 15 publications

References 12 publications

Challenges of Accurate Measurement of Distorted Current and Voltage in the Power Grid by Conventional Instrument Transformers

Challenges of Accurate Measurement of Distorted Current and Voltage in the Power Grid by Conventional Instrument Transformers

Difficulties in producing CT caused by the current ratio regulation in IEC standard and suggestions of modification

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

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