1,720,962 research outputs found
Performance of Practical Receiver Schemes for Impulsive UWB Modulation on a Real MV Power Line Network
No full textComparison of Narrow-Band OFDM PLC Solutions and I-UWB Modulation over Distribution Grids
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Frequency Dielectric Spectroscopy and Dissipation Factor Measurements during Thermal Cycles on Different Types of MV Cable Joints
Full text linkResults of periodic measurements of Dissipation Factor (DF) and Frequency Dielectric Spectroscopy (FDS) on Medium Voltage (MV) cables during thermal cycles, are reported and discussed in this paper. Twelve cables equipped with different types of joints were connected together to form a ring in short-circuit. The ring was energized at rated voltage and current. Temperature cycles with a period of one day (11 hours of heating) were applied by controlling the current. Periodically, each cable was tested separately using both DF and FDS techniques to monitor the ageing progression. This paper focuses on the experimental results obtained testing six new cables provided by different types of new joints while the other six coming from the field, are not considered here. Results obtained testing the six new cables indicate that FDS evaluation is a reliable tool to distinguish the aging progression of the insulation from the seasonal and reversible changes while DF values recorded at different voltage levels show a non-regular behavior particularly in XLPE cables. These results clearly suggest that the systematic use of FDS in condition assessment of underground cables can provide more information on the ageing progression than the traditional DF measurements
Statistical Analysis of Broadband Underground Medium Voltage Channels for PLC Applications
No full textThis work presents a statistical analysis performed on a set of channels that were measured in real-life underground medium voltage power line communication (PLC) networks. The aim is to improve the knowledge of the medium from experimental basis, providing usable and closed-form expressions of the main metrics in order to foster the design of PLC technologies tailored to such challenging scenario. The work targets the 2-40 MHz band, and focuses on the average channel gain (ACG), the root-mean-square delay spread (RMS-DS) and the coherence bandwidth. Furthermore, the work presents the relation between the ACG, the RMS-DS and the network topology, and it infers the capacity as a function of the transmission bandwidth under power spectral density or total power constraints. Some results about the line impedance are also show
Evoluzione della rete di distribuzione, smart grid e tecnologie innovative per il miglioramento della power quality.
No full textFunctional principal component analysis as a versatile technique to understand and predict the electric consumption patterns
Full text linkUnderstanding and predicting the electric consumption patterns in the short-, mid- and long-term, at the distribution and transmission level, is a fundamental asset for smart grids infrastructure planning, dynamic network reconfiguration, dynamic energy pricing and savings, and thus energy efficiency. This work introduces the Functional Principal Component Analysis (FPCA) as a versatile method to both investigate and predict, at different level of spatial aggregation, the consumption patterns. The method was applied to a unique and sensitive dataset that includes electric consumption and contractual information of Milan metropolitan area. The decomposition of the load patterns into principal functions was found to be a powerful method to identify the physical and behavioral causes underlying the daily consumptions, given knowledge of exogenous variables such as calendar and meteorological data. The effectiveness of long-term predictions based on principal functions was proved on Milan's metropolitan area data and assessed on a publicly-available dataset
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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