Behavior of voltage transformers under distorted conditions

Lei, Ting; Cristaldi, L.; Faifer, Marco; Ottoboni, R.; Toscani, Sergio; Cherbaucich, C.; Mazza, Paolo

doi:10.1109/i2mtc.2016.7520344

Cited by 11 publications

(8 citation statements)

References 4 publications

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“…Support to the authors' choice is given by the current literature which is facing the same issue of providing actual or more realistic waveforms to the devices under test. For example, [24][25][26] was done on current transformers, while in [27,28] for the voltage ones.…”

Section: Introductionmentioning

confidence: 99%

Testing of Electrical Energy Meters Subject to Realistic Distorted Voltages and Currents

et al. 2020

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This paper presents a study on revenue active electrical energy meters. The huge installation along the distribution network of these devices made them a key element for energy billing, but also for monitoring the grid status. Hence, it is evident that the relevance of guaranteeing a trusty metering performance, and consequently a proper standardization, is needed. The operation of the meters is regulated by standards harmonized with the European Directive 2014/32/EU (known as MID). Still, and not infrequently, compliance to some legacy standards is declared on the device specifications. Thus, a brief comparison between the latest standards is presented. In particular, the focus was set on evaluating the potential impact of the harmonic disturbances on the energy meter accuracy, since they are omnipresent in the modern power networks. The evaluation has been carried out on three off-the-shelf class B meters by means of a new test procedure that considers realistic and quasi-realistic harmonic disturbances. Such tests showed that realistic harmonic disturbances affect significantly only some energy meters. Therefore, the standards should not neglect this kind of scenario.

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Section: Introductionmentioning

confidence: 99%

Testing of Electrical Energy Meters Subject to Realistic Distorted Voltages and Currents

et al. 2020

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“…Since this requires an adequate experimental setup, including a proper source allowing to apply such complex waveforms, [9] also states that it is allowed to perform accuracy tests by applying only one single harmonic frequency. When looking at the scientific literature, only few works dealing with the potential effects of nonlinearity on the accuracy of voltage instrument transformers can be found [10], [11]. Papers [12], [13] propose the employment of the Best Linear Approximation theory [14] for the metrological characterization of voltage instrument transformers devoted to harmonic measurements.…”

Section: Introductionmentioning

confidence: 99%

Overcoming Frequency Response Measurements of Voltage Transformers: An Approach Based on Quasi-Sinusoidal Volterra Models

Faifer

Laurano

Ottoboni

et al. 2019

IEEE Trans. Instrum. Meas.

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The most recent IEC standards about voltage transformers warn about nonlinearity, which may have significantly impact on the harmonic measurement performance. However, there is a lack of scientific literature about this topic: usually their characterization consists of frequency response measurements, which are clearly not able to capture the nonlinear behavior.In this paper, an innovative approach based on simplified frequency domain polynomial models developed by the authors is proposed. The method is applied to two different medium voltage inductive transformers. Models are identified and validated with a large set of realistic primary waveforms injected by a proper setup. Experimental results confirm the remarkable accuracy of the proposed models especially for low-order harmonics, which are the most affected by nonlinearity.

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“…Many papers report frequency response measurements [13]- [16], but [12] warns to pay special attention on the employed method, since it may significantly affect the results because of nonlinear phenomena. Only few works [17], [18] mention the potential impact of such nonlinearities.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Voltage Instrument Transformers Under Nonsinusoidal Conditions Based on the Best Linear Approximation

Faifer

Laurano

Ottoboni

et al. 2018

IEEE Trans. Instrum. Meas.

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Voltage instrument transformers are usually tested at the rated frequency. In order to assess their performance in measuring harmonic components, typically, the frequency response function (FRF) is evaluated. Therefore, this conventional characterization does not consider nonlinear effects that may have a nonnegligible impact on the accuracy, especially when the transducer under test is represented by an inductive voltage transformer (VT). In this paper, a simple procedure for the characterization of voltage instrument transformers is presented. The method is based on the concept of best linear approximation of a nonlinear system. It requires applying a class of excitation signals that resembles the typical voltage waveforms found in power systems. Results consist of the FRF that permits the best linear compensation of the transducer response, and sample variances that allow quantifying the impact of noise and nonlinearities on the accuracy. The method is presented and explained by means of numerical simulations. After that, it has been applied to the characterization of a conventional inductive VT. Experimental results show how the accuracy of the transducer under test is heavily degraded by nonlinear phenomena when low-order voltage harmonics are considered.

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Behavior of voltage transformers under distorted conditions

Cited by 11 publications

References 4 publications

Testing of Electrical Energy Meters Subject to Realistic Distorted Voltages and Currents

Testing of Electrical Energy Meters Subject to Realistic Distorted Voltages and Currents

Overcoming Frequency Response Measurements of Voltage Transformers: An Approach Based on Quasi-Sinusoidal Volterra Models

Characterization of Voltage Instrument Transformers Under Nonsinusoidal Conditions Based on the Best Linear Approximation

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