Papers by Roberto Tinarelli
Институт проблем экологии и недропользования Академии наук Республики Татарстан (обособленное подразделение Государственного научного бюджетного учреждения «Академия наук Республики Татарстан»), 2020
Sensors, 2022
The distribution network is experiencing a massive deployment of intelligent electronic devices (... more The distribution network is experiencing a massive deployment of intelligent electronic devices (IEDs) such as energy meters, protective devices, and phasor measurement units (PMUs). This phenomenon resulted, on the one hand, in (i) the availability of distributed measurement systems capable of monitoring and collecting measurements from the distribution network, and (ii) increasing awareness of the system operator about the status of the network. On the other hand, such a significant number of devices require to be characterized, over the years, and assessed in both sinusoidal and distorted conditions. However, the characterization process may require a huge investment of money and time considering the low availability of reference instruments and accredited laboratories. To this purpose, this paper presents a simple and fast test procedure, performed with cheap and low-voltage instrumentation, to characterize two off-the-shelf low-power medium-voltage sensors in the power quality ...
Sensors, 2022
Low-Power Instrument Transformers (LPITs) are becoming the first choice for distributed measureme... more Low-Power Instrument Transformers (LPITs) are becoming the first choice for distributed measurement systems for medium voltage networks. However, there are still a lot of challenges related to their operation. Such challenges include their accuracy variation when several influence quantities are acting on them. Among the most significant influence quantities are temperature, electromagnetic field, humidity, etc. Another aspect that increases the importance of studying the LPITs’ accuracy behavior is that, once installed, they cannot be calibrated for several years; hence, one cannot compensate for in-field conditions. Hence, this work aims at introducing a simple type test for a specific LPIT, the Rogowski coil. First, an experimental setup to assess the effect of temperature, humidity, and positioning on the power quality accuracy performance of the Rogowski coil is described. Second, from the results and the experience of the authors it has been possible to design a specific type ...
2018 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 2018
Energies, 2021
Stray capacitances (SCs) are a serious issue in high-voltage (HV) applications. Their presence ca... more Stray capacitances (SCs) are a serious issue in high-voltage (HV) applications. Their presence can alter the circuit or the operation of a device, resulting in wrong or even disastrous consequences. To this purpose, in this work, we describe the modeling of SCs in HV capacitive dividers. Such modeling does not rely on finite element analysis or complicated geometries; instead, it starts from an equivalent circuit of a conventional measurement setup described by the standard IEC 61869-11. Once the equivalent model including the SCs is found, closed expressions of the SCs are derived starting from the ratio error definition. Afterwards, they are validated in a simulation environment by implementing various circuit configurations. The results demonstrate the expressions applicability and effectiveness; hence, thanks to their simplicity, they can be implemented by system operators, researchers, and manufacturers avoiding the use of complicated methods and technologies.
Energies, 2021
The need for accurate measurements and for estimating the uncertainties associated with measures ... more The need for accurate measurements and for estimating the uncertainties associated with measures are two pillars for researchers and metrologists. This is particularly true in distribution networks due to a mass deployment of new intelligent electronic devices. Among such devices, phasor measurement units are key enablers for obtaining the full observability of the grid. The phasor measurement unit performance is mostly evaluated by means of the total vector error, which combines the error on amplitude, phase, and time. However, the total vector error is typically provided merely as a number, that could vary within an unknown interval. This may result into the phasor measurement unit incompliance with the final user expectancies. To this purpose, and with the aim of answering practical needs from the industrial world, this paper presents a closed-form expression that allows us to quantify, in a simple way, the confidence interval associated with the total vector error. The input req...
2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 2020
This paper presents an experimental study on inductive current transformers. Their modelling is s... more This paper presents an experimental study on inductive current transformers. Their modelling is still a key topic among their literature and the related studies are quite vivid. To this purpose, the paper contributes to the improvement of the transformers’ behaviour knowledge under typical operating conditions. In particular, a procedure is proposed to predict ratio error and phase displacement of the current transformer by starting from a fixed loading current and ambient temperature. Moreover, a decomposition procedure is performed to analyse the filtering behaviour and the contribute of the current transformer shunt parameters. Results show the effectiveness of the presented procedure and how the shunt parameters affect the overall ratio error and phase displacement.
Energies, 2021
The digitalization of a medium voltage network requires huge efforts from distributed system oper... more The digitalization of a medium voltage network requires huge efforts from distributed system operators and electric utilities. The main reason is attributed to the costs associated with the replacement or introduction of new intelligent electronic devices capable of collecting and digitalizing current and voltage measurements. To this purpose, this paper introduces a new idea of a stand-alone merging unit (SAMU), which features real-time and hardware-in-the-loop technology, completed with accurate voltage and current sensors. Furthermore, the characterization procedure that allows an evaluation of the metrological performance of a complex device, such as a SAMU, is fully described. From the results, it is highlighted that (i) the developed SAMU is capable of performing highly accurate voltage, current, and power measurements; (ii) the characterization procedure is simple and exploitable for all kinds of SAMUs and other synchronized measurement devices.
2019 IEEE 10th International Workshop on Applied Measurements for Power Systems (AMPS), 2019
The use of Low-Power Instrument Transformers is spreading among the network and Standards are pro... more The use of Low-Power Instrument Transformers is spreading among the network and Standards are providing all the necessary information for their usage. However, practical applications adopt such definition with a certain delay (which could be years) with respect to their publication. To this purpose, the paper presents a simple Rogowski modelling procedure, for nonexperts, to predict the Rogowski output when used under nonstandard conditions. In addition, the procedure allows to have a clear knowledge of each device for further testing. Provided measurement results confirm the effectiveness of the proposed procedure.
Sensors, 2021
The use of capacitive dividers (CDs) in medium-voltage (MV) networks started as simple voltage de... more The use of capacitive dividers (CDs) in medium-voltage (MV) networks started as simple voltage detectors and as rough voltage measurement instruments for protective purposes. Now, with the spread of intelligent electronic devices and renewable energy sources at the distribution level, capacitive dividers are designed and installed to perform accurate voltage measurements. Such a requirement is mandatory when the power quality has to be assessed. Therefore, CDs are currently being used either for power frequency or for high-frequency (supraharmonic- or partial-discharge-level) measurements. In this paper, typical off-the-shelf CDs are studied and modeled to understand how they behave in a wide range of frequencies and when the temperature varies. To this purpose, specific setups and tests have been developed and performed. From the results, it is clear that with proper modeling of CDs, it is possible to exploit them for measuring phenomena in a wide range of frequencies, including th...
Theproblem ofdetermining thelocation offaults in distribution systems canbefacedwithseveral techn... more Theproblem ofdetermining thelocation offaults in distribution systems canbefacedwithseveral techniques. Inthis paper, anapproach based ontheuseofadistributed measurement system isimproved, thenitsperformance isevaluated under different realistic operating conditions ofthenetwork bymeansof simulations. Theresults showthevalidity andtherobustness of proposed method. . ~~~~~~11_.- instant I
In this paper authors present the result of a study oriented to assess the metrological character... more In this paper authors present the result of a study oriented to assess the metrological characteristics of measuring systems used for verifying the variation of the ratio errors and phase displacements of inductive voltage transformers vs. temperature. Experimental results show that the designed equipment as well as the set up realized can be considered as a benchmark for the verification of the variations of ratio errors and phase displacements of up to 0.1-accuracy class voltage transformers vs. temperature. In addition, the sources that more contribute to the uncertainties on the ratio and phase errors have been investigated and discussed in the paper along with suggestions on where to act to further improve the accuracy of the presented set up.
Sensors, 2021
In recent years, the introduction of real-time simulators (RTS) has changed the way of researchin... more In recent years, the introduction of real-time simulators (RTS) has changed the way of researching the power network. In particular, researchers and system operators (SOs) are now capable of simulating the complete network and of making it interact with the real world thanks to the hardware-in-the-loop (HIL) and digital twin (DT) concepts. Such tools create infinite scenarios in which the network can be tested and virtually monitored to, for example, predict and avoid faults or energy shortages. Furthermore, the real-time monitoring of the network allows estimating the status of the electrical assets and consequently undertake their predictive maintenance. The success of the HIL and DT application relies on the fact that the simulated network elements (cables, generation, accessories, converters, etc.) are correctly modeled and characterized. This is particularly true if the RTS acquisition capabilities are used to enable the HIL and the DT. To this purpose, this work aims at emphas...
2019 II Workshop on Metrology for Industry 4.0 and IoT (MetroInd4.0&IoT), 2019
With the purpose of understanding more and more the causes of fault for MV cable-joints this pape... more With the purpose of understanding more and more the causes of fault for MV cable-joints this paper deals the interfacial pressure vs. temperature issue. By starting from results obtained by the authors in the field of cable-joints, firstly a test bed for pressure measurements is developed and characterized. Afterwards temperature test cycles have been defined to measure how temperature affects the interfacial pressure (XLPE/Silicon rubber) inside the cable-joints. Presented results confirm the accuracy of the developed setup and the pressure vs. temperature behaviour of two different cable-joints.
Energies, 2021
Distribution networks are currently subject to a huge revolution in terms of assets being install... more Distribution networks are currently subject to a huge revolution in terms of assets being installed. In particular, the massive spread of renewable energy sources has drastically changed the way of approaching the grid. For example, renewables affected (i) the production of the legacy power plants, (ii) the quality of the supplied energy, decreasing it, (iii) the fault detection and location, etc. To mitigate the significant drawbacks of the renewables’ presence, several intelligent electronic devices have been (and are being) developed and installed among the grid. The aim is to increase grid monitoring and knowledge of its status. However, considering the significant number of nodes of the distribution network, compared to the transmission one, the process of installing new equipment is not effortless and is also quite expensive. This work aims at emphasizing a new concept of distributed monitoring systems, based on the phasor measurement unit’s current measurements, and a control...
Electricity, 2021
Low-power instrument transformers (LPITs) are spreading among the distribution network thanks to ... more Low-power instrument transformers (LPITs) are spreading among the distribution network thanks to their features (e.g., compactness, lightness, enhanced bandwidth, etc.). It is then a fundamental to guide users and manufacturers to a correct usage and manufacturing of the LPITs. Technical committees, which are in charge of writing dedicated standards, often tackle such a task. Focusing on the current type of LPITs, the low-power current transformers (LPCTs), the associated standard is the IEC 61869-10, which is going to be improved in 2021. To this purpose, the work aims at providing new inputs for the future version of such a standard. In particular, the focus is pointed towards the effects of the conductor positioning on the window-type LPCT accuracy. Literature and gained experience in the field are the two pillars that have been used to refine the outcomes of the work, which are provided in terms of suggestions for each technical aspect, as discussed in the standard, related to L...
Sensors, 2020
The accuracy evaluation of instrument transformers is always a key task when proper control and m... more The accuracy evaluation of instrument transformers is always a key task when proper control and management of the power network is required. In particular, accuracy becomes a critical aspect when the grid or the instrumentation itself is operating at conditions different from the rated ones. However, before focusing on the above non-rated conditions, it is important to fully understand the instrument transformer behavior at rated conditions. To this end, this work analyzed the accuracy behavior of legacy, inductive, and low-power voltage transformers over long periods of time. The aim was to find patterns and correlations that may be of help during the modelling or the output prediction of voltage transformers. From the results, the main differences between low-power and inductive voltage transformers were pointed out and described in detail.
Sensors, 2020
The instrument transformers scenario is moving towards the adoption of a new generation of low-po... more The instrument transformers scenario is moving towards the adoption of a new generation of low-power instrument transformers. This disruptive change also requires that the modeling, characterization, and testing of those devices must be improved. Therefore, this study focuses on a smart approach developed by the authors in a previous study to estimate the output of low-power voltage transformers (LPVT). The approach—which is based on a sort of modeling in the frequency domain (the so-called sinc-response)—allows obtaining the behavior of the LPVT at rated and distorted conditions. Experimental tests performed on off-the-shelf devices confirm the applicability and effectiveness of the proposed approach when estimating the output response of LPVTs.
Sensors, 2020
The scenario of instrument transformers has radically changed from the introduction of the Low-Po... more The scenario of instrument transformers has radically changed from the introduction of the Low-Power version, both passive and active. The latter type, typically referred to as Electronic Instrument Transformers (EITs), has no dedicated standard within the IEC 61869 series yet. To this purpose, in the authors’ opinion, it is worth understanding how the limits of typical disturbances affecting EITs should be standardized. In particular, after a brief review of the standards, the work presented a mathematical approach to determine the sources of signal disturbances influence, which affect the rms value, on the ratio error. From the results, we discussed that the emergence of disturbances generated within the EIT is a critical aspect to be studied with data of typical off-the-shelf devices. Therefore, to guarantee a correct operation of the devices, a proper standardization of the sources of disturbance should be provided.
IEEE Transactions on Instrumentation and Measurement, 2020
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Papers by Roberto Tinarelli