Transformation of Transient Overvoltages by Inductive Voltage Transformers

Kaczmarek, M.; Brodecki, D.

doi:10.3390/s21124167

Cited by 12 publications

(4 citation statements)

References 22 publications

(38 reference statements)

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“…The transformation accuracy of higher harmonics by the inductive VTs is limited by the resonance phenomenon. Its frequency mainly depends on the size (number of turns and layers) of the primary winding resulting from the required RMS value of their rated primary voltage [3,36]. Thus, while 15 kV inductive VTs may ensure wide frequency operation up to 5 kHz, an increase in the RMS value of the primary voltage may result in a decrease in the resonance frequency to only 250 Hz for HV units such as 420 [3,19,20,37,40].…”

Section: Summary Of the Results Of The Inductive It's Transformation ...mentioning

confidence: 99%

“…According to the analysis presented in papers [3,36], the parasitic capacitance and leakage inductance of the primary winding of the inductive VT are divided into parts to properly reproduce its multi-resonance properties. The conductive path to ground of each layer of the primary winding is formed by the partial equivalent capacitance of the primary winding to ground, which results from the parasitic capacitance between each layer of the winding.…”

Section: Inductive Vt's Resonance For Higher Harmonics Of the Distort...mentioning

confidence: 99%

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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: Summary Of the Results Of The Inductive It's Transformation ...mentioning

confidence: 99%

Section: Inductive Vt's Resonance For Higher Harmonics Of the Distort...mentioning

confidence: 99%

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

Kaczmarek

Stano

2023

Energies

Self Cite

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“…Table 2 proposes a simplified possible test range of harmonic and interharmonic components to assess the ITs' performance according to indications found in the review of in force standards and scientific literature [17], [18], [19], [20].…”

Section: Table 2 Possible Test Range Of Harmonic and Interharmonic Co...mentioning

confidence: 99%

Evaluation of Voltage Transformers’ Accuracy in Harmonic and Interharmonic Measurement

Crotti

D’Avanzo

Landi

et al. 2022

IEEE Open J. Instrum. Meas.

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The measurement of Power Quality (PQ), generally performed at Low Voltage (LV) level, is gaining more and more importance also at the Medium Voltage (MV) level, due to the increasing presence of switching power converters (both loads or generators) directly connected to MV grids. In this case, the use of Voltage Transformers (VTs) is unavoidable to scale voltage down to amplitudes compatible with the input ranges of PQ instruments. However, the current absence of an international standard dealing with VTs used for PQ measurements leaves the manufacturers and the users in a situation of complete uncertainty, since different products can have performance specifications tested and stated in completely different ways. This paper aims at defining an integrated approach for the evaluation of VTs accuracy used for PQ measurements, focusing on harmonics and interharmonics. The paper provides experimental results of the tests performed on a MV inductive VT according to the proposed procedure. As a result, it is demonstrated that VT accuracy in the measurement of a specific phenomenon should be evaluated with complex waveforms including the contemporary presence of different PQ phenomena.INDEX TERMS Instrument transformers, voltage transformers, harmonics, interharmonics, power system measurements, power quality, accuracy.

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“…The papers [ 5 , 6 ] investigate the error contributions of VTs and CTs in the measurement of first harmonics. The paper [ 7 ] deals with the study of inductive VT performance in the measurement of transient overvoltage. However, a comprehensive analysis of IT performance in the presence of all the PQ phenomena is still lacking, as well as a proposal of a related measurement procedure.…”

Section: Introductionmentioning

confidence: 99%

How Instrument Transformers Influence Power Quality Measurements: A Proposal of Accuracy Verification Tests

Crotti

Chen

Çaycı

et al. 2022

Sensors

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The integration of renewable energy sources on a large scale in the electrical energy distribution systems, as well as the widespread of non-linear loads, has led to a significant increase in power quality (PQ) disturbances. For this reason, PQ monitoring is also becoming a key task in medium voltage (MV) grids. The measurement of PQ at MV levels can only be performed using instrument transformers (ITs) to scale down the level of voltage and current to levels suitable for the input stage of PQ instruments. However, no international standards currently require the verification of the errors introduced by ITs in the measurement of PQ phenomena. Moreover, this issue is only partially addressed in the scientific literature, where papers dealing with specific and limited aspects of the problem can be found. For this reason, this paper aims to comprehensively assess the issue, proposing IT accuracy verification tests for different PQ parameters. First, a set of PQ phenomena relevant for IT testing is chosen, as well as the associated ranges of variation, based on a review of the enforced standards and the scientific literature. For each selected PQ phenomenon, possible performance indices and test waveforms are proposed. Finally, the proposed procedure is validated by applying it to the characterization of two different types of commercial voltage transformers.

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Transformation of Transient Overvoltages by Inductive Voltage Transformers

Cited by 12 publications

References 22 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

Evaluation of Voltage Transformers’ Accuracy in Harmonic and Interharmonic Measurement

How Instrument Transformers Influence Power Quality Measurements: A Proposal of Accuracy Verification Tests

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