1,721,219 research outputs found
Predizione della affidabilità di un sistema per l’analisi della qualità dell’energia elettrica mediante l’Impiego del modello di Markov
No full textA Simple Classification Method for Evaluating Influence Factors Affecting Instrument Transformer Accuracy
No full textIndividual or Group Error Compensation: An Experimental Demonstration on the Frequency Response of Rogowski Coils
No full textInstrument transformers (ITs) play a crucial role as interface elements in power systems, enabling the acquisition of electrical quantities necessary for assessing system health. Consequently, they have been a focal point in research, with numerous studies aiming to enhance their performance in field applications. One critical issue affecting the accuracy of ITs is the differentiation between type and routine tests, which underscores the need for individual or group error compensation. This study investigates the limitations of group error compensation techniques for ITs, providing experimental evidence to demonstrate their potential drawbacks. Specifically, low-power current transformers, such as Rogowski coils, were evaluated to examine variability among individual devices. The study tested three series of six devices from three manufacturers under varying temperature conditions. The findings reveal significant variability among the tested devices, indicating that group error compensation often degrades the accuracy of ITs. These results highlight the importance of considering individual error characteristics to ensure optimal performance in practical applications
Analysis of the spectral degradation of LEDs’ emissions under temperature stress conditions
No full textConducted Emission and Power Line Filter Design of a Three-phase Grid-connected Battery Charger for Automotive Application
No full textThe growing diffusion of off-board battery chargers for electric vehicles leads to a severe increase in electromagnetic interference (EMI) in power grids, and in particular of conducted disturbances. The battery chargers must therefore be equipped with suitable power line filters to reduce conducted emission (CE). In order to efficiently design the threephase filter, the modal decomposition of the disturbance is exploited. In three-phase systems both the differential mode (DM) and common mode (CM) components of the specific phase disturbances generally contribute differently to the overall CE. This paper shows a simple methodology for the design of a threephase EMI filter using a setup capable of simultaneously measuring the conducted disturbances on each phase and directly calculating the modal components. The method is applied to a 25 kW three-phase off-board battery charger
Uncertainty sources analysis of a calibration system for the accuracy vs. temperature verification of voltage transformers
No full textThe paper deals with the investigation of accuracy vs. temperature variation of inductive instrument transformers. There is still a lack of literature on this specific and nowadays very important topic. In previous works, authors presented results on effects of temperature on voltage instrument transformers accuracy. In this paper the study continues with the uncertainty sources analysis which affects the calibration setup previously proposed. To this purpose, the metrological characterization along with the Monte Carlo method have been applied in order to highlight the main positive features of the calibration setup. Results of such procedures are presented
Effects of Mechanical Pressure on the Tangent Delta of MV Cable Joints
No full textMedium-voltage cable joints are one of the critical components of the distribution networks. They represent the first cause of faults and outages. Among the others, partial discharge, dielectric, and temperature measurements are the typical tests performed for investigating over the early aging of such critical components. In this paper, a new study has been completed correlating the cable joint tangent delta (Tanδ) value to the external pressure applied on the insulating material surrounding the joint. Results confirm the presumed correlation. In fact, an increase of pressure results in a Tanδ decrease, hence in an extension of the cable joint working life
Use of COMTRADE Fault Current Data to Test Inductive Current Transformers
No full textThis paper presents a study on the inductive current transformer behaviour when subjected to distorted actual waveforms. Typical tools adopted to deal with such a condition, as the well-known ratio error, phase error, frequency response, etc. not always provide satisfactory results in all the possible operating condition. In addition, Standards lack in detailing which actual distorted waveforms need to be used to test the transformers. To this purpose, the paper introduces both the use of particular actual fault current waveforms and a simple index for testing the performance of the transformer. Preliminary results show its helpfulness when applied to particular waveforms
A General Easy-to-use Expression for Uncertainty Evaluation in Residual Voltage Measurement
Full text linkThe 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
Comprehensive Forecasting of Electrical Quantities in an Educational Building via Artifical Intelligence-Driven Distributed Measurement System
Full text linkRecent environmental concerns have heightened attention toward new solutions
across all fields to mitigate human impact. The power system community is also deeply
committed to addressing this issue, with research increasingly focused on sustainable
practices. For instance, there is a growing trend in designing new buildings to be net-zero
emitters, while older structures are being retrofitted for energy efficiency to achieve similar
goals. To this purpose, the study aims to enhance the energy management capabilities of an
educational building by implementing a smart infrastructure. Equipped with photovoltaic
panels and a distributed measurement system, the building captures voltage and current
data and calculates power. These electrical quantities are then forecasted through an AI-
driven framework that manages the data. The paper details the AI model used, including
its experimental validation. The results show that the system provides reliable forecasts
of electrical parameters. The evaluation of the distributed measurement system and the
collected data offers valuable insights, which support more informed actions for optimizing
energy management and system performance. A key novelty of this study lies in the
exploration of model generalization across measurement nodes. This approach is supported
by the correlation analysis of data, which highlights the potential for accurate predictions
in case of data gaps. Moreover, the ease of deployment and the practical application of the
system were highlighted as key factors for scalability, allowing for potential adaptation in
similar infrastructures
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