Low power voltage transformer accuracy class effects on the residual voltage measurement

Tinarelli

2020

Sensors

Self Cite

With the spread of new Low-Power Instrument Transformers (LPITs), it is fundamental to provide models and characterization procedures to estimate and even predict the LPITs’ behavior. In fact, distribution system operators and designers of network models are looking for all forms of information which may help the management and the control of power networks. For this purpose, the paper wants to contribute to the scientific community presenting a smart characterization procedure which easily provides sufficient information to predict the output signal of a Low-Power Current Transformer (LPCT), the Rogowski coil. The presented procedure is based on a synthetized signal applied to the Rogowski coil. Afterwards, the validity of the procedure is assessed within the Matlab environment and then by applying it on three off-the-shelf Rogowski coils. Simulations and experimental tests and results involving a variety of distorted signals in the power quality frequency range and by adopting a quite simple measurement setup demonstrated the effectiveness and the capability of the procedure to correctly estimate the output of the tested device.

Section: Introductionmentioning

confidence: 99%

Smart Characterization of Rogowski Coils by Using a Synthetized Signal

Tinarelli

2020

Sensors

Self Cite

“…The second is the fact that the measurements performed by the LPITs are collected and sent to intelligent electronic devices, phasor measurement units, etc. [38,39], which run algorithms [40][41][42][43][44] developed and implemented to manage the distribution networks, including control of the protective devices. Therefore, if the accuracy and the measurements obtained with the LPITs are worsened/corrupted by external factors, then all the data processing that follows is affected by the propagation of uncertainty and, in most cases, they become useless or no longer reliable.…”

Section: Introductionmentioning

confidence: 99%

Calibration Procedure to Test the Effects of Multiple Influence Quantities on Low-Power Voltage Transformers

Tinarelli

2020

Sensors

Self Cite

The article presents a study on low-power voltage transformers (LPVTs). Considering their increasing spread among Smart Grids, it is fundamental to assess their accuracy behavior in as realistic conditions as possible. Therefore, this article presents a detailed calibration procedure to test LPVTs’ accuracy when various external influence quantities are simultaneously acting on them. In the calibration procedure, the considered quantities are frequency, air temperature, and external electric field. Afterwards, the designed procedure is applied on three different off-the-shelf LPVTs using a measurement setup developed in a laboratory environment. The presented results (i) confirm the easy applicability of the designed calibration procedure; (ii) highlight the various effects of the influence quantities on the accuracy of different types of LPVTs; (iii) confirm the need to include more realistic tests, like the type-tests presented, into the standards to appreciate a wider set of possible in-field behaviors.

“…The paper is aimed to present a novel study developed from the results of the related paper [11] to correlate the uncertainty affecting the measurement of the residual voltage with the accuracy class of the LPVTs.…”

Section: Introductionmentioning

confidence: 99%

A General Easy-to-Use Expression for Uncertainty Evaluation in Residual Voltage Measurement

Baldi

IEEE Trans. Instrum. Meas.

et al. 2020

Self Cite

The paper addresses one of the new and most important issues arising when Low Power Voltage Transformers (LPVTs) are used in power network substations for evaluating, among others, the residual voltage measurement. Conversely to open-triangle inductive instrument transformers, the use of phase voltage transformers for measuring the residual voltage gets challenging due to the very high accuracy required for the three LPVTs. In the paper, a general expression to estimate the residual voltage measurement uncertainty, starting from the LPVTs accuracy, is presented. The effectiveness of the proposed approach is then confirmed with both Monte Carlo simulations and actual measurements on a general three-phase system.