scholarly journals Comparison of Measurement Methods of LV Grid Access Impedance in the Frequency Range Assigned to Nb‑Plc Technologies

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1155 ◽  
Author(s):  
Igor Fernández ◽  
David de la Vega ◽  
Dominique Roggo ◽  
Robert Stiegler ◽  
Lino Capponi ◽  
...  
Keyword(s):  
Distribution System ◽  
Low Voltage ◽  
Collaborative Work ◽  
Frequency Range ◽  
Electrical Grid ◽  
Power Line Communications ◽  
Theoretical Approaches ◽  
High Degree ◽  
Impedance Characterization

The paper presents and evaluates three advanced methods for the characterization of the low-voltage (LV) grid access impedance for the frequency range assigned to Narrow Band-Power Line Communications (NB-PLC): 9 kHz to 500 kHz. This study responds to the recent demand from both regulatory bodies and Distribution System Operators about the need for accurate and validated methods for this frequency band, due to the limited knowledge of the impedance values in the electrical grid and their influence on NB-PLC transmission channels. In this paper, the results of a collaborative work to develop different proposals to overcome the challenges for the proper characterization of the frequency and time-varying grid impedance, from different theoretical approaches, are presented. The methods are compared in a controlled and isolated scenario: the impedance characterization of passive filters. Then, the results are validated two-fold: first, against theoretical simulations, based on the schematics provided by the manufacturer, and second, against the measurement results of a precision impedance meter, used as a reference of accuracy. The results demonstrate a high degree of precision of the three proposals to characterize the access impedance of the LV grid.

scholarly journals Field Trials for the Characterization of Non-Intentional Emissions at Low-Voltage Grid in the Frequency Range Assigned to NB-PLC Technologies

Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 1044 ◽  
Author(s):  
Igor Fernández ◽  
David de la Vega ◽  
Amaia Arrinda ◽  
Itziar Angulo ◽  
Noelia Uribe-Pérez ◽  
...  
Keyword(s):  
Smart Grid ◽  
Error Detection ◽  
Low Voltage ◽  
Field Trials ◽  
Grid Services ◽  
Frequency Range ◽  
Industrial Facilities ◽  
Electrical Grid ◽  
Error Detection And Correction

The paper describes the results of a measurement campaign to characterize the non-intentional emissions (NIE) that are present in the low voltage section of the electrical grid, within the frequency range assigned to narrowband power line communications (NB-PLC), from 20 kHz to 500 kHz. These NIE may severely degrade the quality of the communications and, in some cases, even isolate the transmission devices. For this reason, the identification and characterization of these perturbations are important aspects for the proper performance of the smart grid services based on PLC. The proper characterization of NIE in this frequency range is a key aspect for the selection of efficient configurations to find the best trade-off between data throughput and robustness, or even for the definition of new improved error detection and correction methods. The huge number of types of NIE, together with the wide variety of grid topologies and loads distribution (density and location of homes and industrial facilities) are great challenges that complicate the thorough characterization of NIE. This work contributes with results from field trials in different scenarios, the identification of different types of NIE and the characterization both in time and frequency domains of all the registered disturbances. This contribution will be helpful for a better knowledge of the electrical grid as a transmission medium for PLC and, therefore, for evaluating the appropriateness of different robustness techniques to be applied in the next generation of smart grid services.

CHARACTERIZATION OF THE RESISTIVE AND INDUCTIVE LOADS OF AN ENERGY DISTRIBUTION SYSTEM WITH JULIA FRACTAL SETS

Fractals ◽  
2020 ◽  
Vol 28 (05) ◽  
pp. 2050082
Author(s):  
HÉCTOR A. TABARES-OSPINA ◽  
MAURICIO OSORIO
Keyword(s):  
Energy Distribution ◽  
Distribution System ◽  
Fractal Geometry ◽  
Electrical Load ◽  
Fractal Sets ◽  
Electric Distribution System ◽  
Theoretical Approaches ◽  
Fractal Space ◽  
Graphic Pattern

The present paper characterizes the resistive and inductive loads of an electric distribution system by Julia fractal sets, in order to discover other observations enabling the elevation of new theoretical approaches. The result shows that indeed the electrical load reflects a clear graphic pattern in the fractal space of the Julia sets. This result, then, is a new contribution that extends the universal knowledge about fractal geometry.

scholarly journals A comparative study on AC/DC analysis of an operational low voltage distribution system

2021 ◽  
Vol 10 (3) ◽  
pp. 193
Author(s):  
Cihan Katar ◽  
Cengiz Polat Uzunoglu
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Low Voltage ◽  
Solar Panels ◽  
Power Losses ◽  
Voltage Distribution ◽  
Electrical Grid ◽  
Safety Regulations ◽  
Voltage Drops ◽  
Novel Approach

In the near future, the digitalizing world will continue to improve and the need for DC based devices will be increased beyond doubt. Today’s electrical grid is strictly dependent on AC-DC rectifiers. Each conversion process means additional power losses and signal quality deteriorations for the network. In addition, networks which are fed by batteries and renewable sources such as solar panels, and wind turbines are suffering from conversion-based power losses. In this respect, the idea of switching to DC on the low voltage side of the networks has become an intriguing subject. In this study, the applicability and efficiency of the low voltage direct current (LVDC) concept for low voltage distribution systems is discussed and a sample LVDC distribution system is analyzed. In this operational residential application electrical transient analyzer program (ETAP) is employed for comparison of different voltage levels such as 110 V<sub>DC</sub>, 250 V<sub>DC</sub>, 320 V<sub>DC</sub> and conventional 220/380 V<sub>AC</sub>. As a novel approach different DC voltage levels are compared with typical AC system in detail. Comparative analysis is conducted for safety regulations, voltage drops, current carrying capacities, power consumption and harmonic calculation of the proposed system. In this respect applicability, possible drawbacks and future aspects of LVDC systems are interpreted.

scholarly journals Adaptive Volt-Var Control Algorithm to Grid Strength and PV Inverter Characteristics

2021 ◽  
Vol 13 (8) ◽  
pp. 4459
Author(s):  
Toni Cantero Gubert ◽  
Alba Colet ◽  
Lluc Canals Casals ◽  
Cristina Corchero ◽  
José Luís Domínguez-García ◽  
...  
Keyword(s):  
Distribution System ◽  
Control Algorithm ◽  
Low Voltage ◽  
Control Function ◽  
Accurate Information ◽  
Voltage Sensitivity ◽  
Sensitivity Matrix ◽  
Electrical Grid ◽  
Pv Inverter ◽  
Voltage Deviation

The high-penetration of Distributed Energy Resources (DER) in low voltage distribution grids, mainly photovoltaics (PV), might lead to overvoltage in the point of common coupling, thus, limiting the entrance of renewable sources to fulfill the requirements from the network operator. Volt-var is a common control function for DER power converters that is used to enhance the stability and reliability of the voltage in the distribution system. In this study, a centralized algorithm provides local volt-var control parameters to each PV inverter, which are based on the electrical grid characteristics. Because accurate information of grid characteristics is typically not available, the parametrization of the electrical grid is done using a local power meter data and a voltage sensitivity matrix. The algorithm has different optimization modes that take into account the minimization of voltage deviation and line current. To validate the effectiveness of the algorithm and its deployment in a real infrastructure, the solution has been tested in an experimental setup with PV emulators under laboratory conditions. The volt-var control algorithm successfully adapted its parameters based on grid topology and PV inverter characteristics, achieving a voltage reduction of up to 25% of the allowed voltage deviation.

Induced polarization and transient electromagnetic surveys for the characterization of a graphite ore

2020 ◽  
Author(s):  
Adrian Flores Orozco ◽  
Lukas Aigner ◽  
Timea Katona ◽  
Matthias Bücker ◽  
Philipp Zehetgruber ◽  
...  
Keyword(s):  
Low Voltage ◽  
Numerical Models ◽  
Induced Polarization ◽  
Data Sets ◽  
Imaging Data ◽  
Frequency Range ◽  
Field Surveys ◽  
Transient Electromagnetic ◽  
Imaging Results

&lt;p&gt;The prospection of electrical conductors and semi-conductors has been one of the classical applications of the induced polarization (IP) method, with recent laboratory studies permitting to gain a deeper insight into the parameters controlling the polarization response. However, the application of electrochemical models developed for laboratory measurements has been rarely taken into field-scale imaging data sets. To fill this gap, here we discuss IP imaging results collected in Zettlitz (Austria), a former quarry operated between 1855 and 1967 for the extraction of graphite, an electrical conductor. The general goal of the geophysical survey is to characterize the geometry and volume of the residual graphite at the site. To this end, frequency-domain IP imaging measurements were collected along 10 main transects using different geometries, with selected data sets collected in the frequency range between 0.25 and 1 Hz to gain information about the frequency-dependence of the electrical properties. As expected, initial measurements revealed a high IP response in the graphite-rich areas. Nevertheless, the high electrical conductivity of the materials resulted in low voltage readings and an important decrease in the signal-to-noise ratio for deep measurements; thus, significantly reducing the depth of investigation. To overcome this limitation, we conducted measurements at areas of interest using transient electromagnetic (TEM) soundings, which are favored by the high conductivity of the targeted graphite and permit a better delineation of the contact to the calcareous host-rock. Initial analysis of the TEM data revealed a poor consistency with the electrical models retrieved from the IP surveys. However, taking into account the IP effect within the inversion of the TEM data significantly improved the consistency in the subsurface models resolved by the different methods. In order to resolve for adequate parameters for the modeling of TEM signatures, IP measurements were also collected at relevant positions in the frequency-range between 0.01 and 10000 Hz, with a high accuracy electrical impedance spectrometer. Further IP measurements were also collected in rock samples in the laboratory to aid in the interpretation of the field surveys and to permit the numerical modeling of the electrical signatures using a recently proposed electrochemical model. Our results demonstrate that the combination of IP and TEM surveys provide an improved modeling of the field signatures and, thus, a better characterization of the site. Additionally, we discuss the applicability of existing empirical and numerical models for the quantitative interpretation of field surveys.&lt;/p&gt;

scholarly journals Adaptive Volt-VAr Control Algorithm to Grid Strength and PV Inverter Characteristics

2021 ◽  
Author(s):  
Toni Cantero Gubert ◽  
Alba Colet ◽  
Lluc Canals Casals ◽  
Cristina Corchero ◽  
Jose Luís Domínguez-García ◽  
...  
Keyword(s):  
Distribution System ◽  
Control Algorithm ◽  
Low Voltage ◽  
Accurate Information ◽  
Voltage Sensitivity ◽  
Sensitivity Matrix ◽  
Electrical Grid ◽  
Pv Inverter ◽  
Control Functions ◽  
Voltage Deviation

High-penetration of Distributed Energy Resources (DER) in low voltage distribution grids, mainly photovoltaics (PV), might lead to overvoltage in the point of common coupling. Volt-VAr is one of the common control functions for DER power converters used to enhance the stability and the reliability of the voltage in the distribution system and, thus, fulfilling the network operator requirements. In this study, a centralized algorithm will provide local Volt-VAr control parameters to each PV inverter, based on the electrical grid characteristics where each equipment is installed. Since accurate information of grid characteristics is typically not available, the parametrization of the electrical grid is done using power meter data in DER location and a voltage sensitivity matrix. The algorithm has different optimization modes to both minimize voltage deviation and line current. In order to validate the effectiveness of the algorithm and its deployment in real infrastructure, it has been tested in an experimental setup with PV emulators in a set of 5-day tests. Volt-VAr control algorithm successfully adapted its parameters based on grid topology and PV inverter characteristics, achieving a voltage reduction up to 25% of the allowed voltage deviation.

Characterization of RF Sputtered ZnO Piezoelectric Films Using Transmission Electron Microscope

1975 ◽  
Vol 33 ◽  
pp. 86-87
Author(s):  
Kemining W. Yeh ◽  
Richard S. Muller ◽  
Wei-Kuo Wu ◽  
Jack Washburn
Keyword(s):  
Integrated Circuit ◽  
Acoustic Waves ◽  
New Technology ◽  
Surface Acoustic Waves ◽  
Electromechanical Properties ◽  
Leading Role ◽  
Saw Devices ◽  
Transmission Electron ◽  
High Degree

Considerable and continuing interest has been shown in the thin film transducer fabrication for surface acoustic waves (SAW) in the past few years. Due to the high degree of miniaturization, compatibility with silicon integrated circuit technology, simplicity and ease of design, this new technology has played an important role in the design of new devices for communications and signal processing. Among the commonly used piezoelectric thin films, ZnO generally yields superior electromechanical properties and is expected to play a leading role in the development of SAW devices.

Development and Evaluation of a Fast Voltage Calculation Method for Low-Voltage Distribution System

2013 ◽  
Vol 133 (4) ◽  
pp. 343-349
Author(s):  
Shunsuke Kawano ◽  
Yasuhiro Hayashi ◽  
Nobuhiko Itaya ◽  
Tomihiro Takano ◽  
Tetsufumi Ono
Keyword(s):  
Calculation Method ◽  
Distribution System ◽  
Low Voltage ◽  
Voltage Distribution
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