scholarly journals Virtual Indicative Broadband over Power Lines Topologies for Respective Subclasses by Adjusting Channel Attenuation Statistical Distribution Parameters of Statistical Hybrid Models (Class Maps) – Part 2: Numerical Results for the Overhead and Underground Medium-Voltage Power Grids

2019 ◽  
Vol 5 (3) ◽  
pp. 258-281
Author(s):  
Athanasios Lazaropoulos
Keyword(s):  
Hybrid Models ◽  
Numerical Results ◽  
Statistical Distribution ◽  
Power Grids ◽  
Power Lines ◽  
Medium Voltage ◽  
Distribution Parameters

scholarly journals Investigation of the Effects of the Arc Fault Resistance and Transient Resistance on the Overcurrent Ground Relay Protection Setting in Medium Voltage Electrical Power Lines

2020 ◽  
Vol 4 (1) ◽  
pp. 67-72
Author(s):  
Plamen Antonov Stanchev ◽  
Mediha Enver Mehmed-Hamza
Keyword(s):  
Power Transformer ◽  
Electrical Power ◽  
Relay Protection ◽  
Power Grids ◽  
Power Lines ◽  
Medium Voltage ◽  
Fault Resistance ◽  
Ground Fault ◽  
Determining Factors ◽  
Transient Voltages

In the medium voltage electrical power lines, the most common fault is the phase to ground fault. The determining factors for selection of the neutral grounding mode of the medium voltage electrical power lines are the selectivity of the relay protection, the transient voltages during phase to ground fault, the magnitude of the fault currents, etc. The paper studies the influence of the transient resistance of phase to ground fault on the selectivity and sensitivity of the earth fault protection when the neutral of the power transformer is grounded through active resistance in medium voltage power grids.

scholarly journals Modeling Airtanker Flight Distance between Concurrent Fires: The Development and Use of Statistical Distribution Parameters

2008 ◽  
Vol 54 (1) ◽  
pp. 47-57
Author(s):  
Francis E. Greulich
Keyword(s):  
System Design ◽  
Analytical Methods ◽  
Statistical Distribution ◽  
Flight Distance ◽  
Design Parameters ◽  
Initial Attack ◽  
System Planning ◽  
Protection Zone ◽  
Transfer Activity ◽  
Distribution Parameters

Abstract Airtankers, while actively engaging in initial attack, are sometimes reassigned and flown directly to another randomly occurring initial attack fire. Airtanker system planning that means to incorporate this fire-to-fire transfer activity needs information about the flight distance between these randomly located fires. Moments of the distance distribution, derived in this article, can be used to characterize and evaluate fire-to-fire airtanker dispatch within and between protection areas. A hypothetical example illustrates how a proposed change in an airtanker protection zone can affect not only airbase-to-fire flight distance but also fire-to-fire flight distance. In this example, the expected airbase-to-fire distance and the expected total transfer-flight distance are both significantly reduced, but at the same time, somewhat unexpectedly, the average fire-to-fire flight distance actually increases. The discovery and quantification of such unanticipated results can potentially influence airtanker system design. These key system design parameters can now be obtained through the exceedingly fast and accurate analytical methods presented here.

scholarly journals A Lightweight Scheme to Authenticate and Secure the Communication in Smart Grids

2018 ◽  
Vol 8 (9) ◽  
pp. 1508 ◽  
Author(s):  
Israa Aziz ◽  
Hai Jin ◽  
Ihsan Abdulqadder ◽  
Zaid Hussien ◽  
Zaid Abduljabbar ◽  
...  
Keyword(s):  
Smart Grids ◽  
Electrical Power ◽  
Distribution Networks ◽  
Power Grids ◽  
Control Center ◽  
Medium Voltage ◽  
Authentication Mechanism ◽  
Computational Overhead ◽  
Automation Equipment ◽  
Lightweight Authentication

Self-reconfiguration in electrical power grids is a significant tool for their planning and operation during both normal and abnormal conditions. The increasing in employment of Intelligent Electronic Devices (IEDs), as well as the rapid growth of the new communication technologies have increased the application of Feeder Automation (FA) in Distribution Networks (DNs). In a Smart Grid (SG), automation equipment, such as a Smart Breaker (SB), is used. Using either a wired or a wireless network or even a combination of both, communication between the Control Center (CC) and SBs can be made. Nowadays, wireless technology is widely used in the communication of DNs. This may cause several security vulnerabilities in the power system, such as remote attacks, with the goal of cutting off the electrical power provided to significant consumers. Therefore, to preserve the cybersecurity of the system, there is a need for a secure scheme. The available literature investments proposed a heavyweight level in security schemes, while the overhead was not considered. To overcome this drawback, this paper presents an efficient lightweight authentication mechanism with the necessary steps to ensure real-time automatic reconfiguration during a fault. As a first stage, authentication will be made between CC and SB, SB then sends the information about its status. To ensure the integrity of the authentication exchange, a hash function is used, while the symmetric algorithm is used to ensure privacy. The applicability of the suggested scheme has been proved by conducting security performance and analysis. The proposed scheme will be injected on ABB medium voltage breaker with the REF 542plus controller. Therefore, the probable benefit of the suggested scheme is the contribution to provide more flexibility for electrical utilities in terms of reducing the overall computational overhead and withstanding to various types of attacks, while also opening new prospects in FA of SGs.

scholarly journals Bird mortality on medium-voltage power lines in the Czech Republic

2019 ◽  
Vol 13 (1) ◽  
pp. 27-44
Author(s):  
Vlasta Škorpíková ◽  
Václav Hlaváč ◽  
Milan Křápek
Keyword(s):  
Czech Republic ◽  
Point Of View ◽  
The Other ◽  
Power Lines ◽  
Mitigation Measures ◽  
Birds Of Prey ◽  
The Czech Republic ◽  
Medium Voltage ◽  
Bird Mortality ◽  
Straight Lines

Abstract In 2015–2016, 6,429 km medium-voltage power lines with 76,430 pylons were checked for bird mortality in the Czech Republic. 1,326 bird victims of power lines were found, 156 of which died after collisions, and 1,170 birds were electrocuted. They belonged to 60 species from 12 orders, and birds of prey made up almost half of all victims. Steel pylons bearing several cross-arms including upper and crosswise jumpers were identified as most dangerous from the electrocution point of view. On the other hand, pylons in straight lines with Pařát cross-arms (triangular arrangement of conductors without any horizontal bar) were among the least dangerous, and when they had a simple perch fitted below the cross-arm, no mortality was recorded. But these pylons are new in practice and despite becoming widely used recently, they form less than one tenth of all pylons in the Czech Republic. On other pylons various types of mitigation measures have been installed. Commonly used plastic covers and plastic strips have proved to be especially effective, but only in cases when they are undamaged and correctly installed.

scholarly journals Broadband over Power Lines Systems Convergence: Multiple-Input Multiple-Output Communications Analysis of Overhead and Underground Low-Voltage and Medium-Voltage BPL Networks

2013 ◽  
Vol 2013 ◽  
pp. 1-30 ◽  
Author(s):  
Athanasios G. Lazaropoulos
Keyword(s):  
Modal Analysis ◽  
Review Paper ◽  
Low Voltage ◽  
Multiple Input Multiple Output ◽  
Power Lines ◽  
Mimo Channels ◽  
Medium Voltage ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Value Decomposition

This review paper reveals the broadband potential of overhead and underground low-voltage (LV) and medium-voltage (MV) broadband over power lines (BPL) networks associated with multiple-input multiple-output (MIMO) technology. The contribution of this review paper is fourfold. First, the unified value decomposition (UVD) modal analysis is introduced. UVD modal analysis is a new technique that unifies eigenvalue decomposition (EVD) and singular value decomposition (SVD) modal analyses achieving the common handling of traditional SISO/BPL and upcoming MIMO/BPL systems. The validity of UVD modal analysis is examined by comparing its simulation results with those of other exact analytical models. Second, based on the proposed UVD modal analysis, the MIMO channels of overhead and underground LV and MV BPL networks (distribution BPL networks) are investigated with regard to their inherent characteristics. Towards that direction, an extended collection of well-validated metrics from the communications literature, such as channel attenuation, average channel gain (ACG), root-mean-square delay spread (RMS-DS), coherence bandwidth (CB), cumulative capacity, capacity complementary cumulative distribution function (CCDF), and capacity gain (GC), is first applied in overhead and underground MIMO/LV and MIMO/MV BPL channels and systems. It is found that the results of the aforementioned metrics portfolio depend drastically on the frequency, the power grid type (either overhead or underground, either LV or MV), the MIMO scheme configuration properties, the MTL configuration, the physical properties of the cables used, the end-to-end distance, and the number, the electrical length, and the terminations of the branches encountered along the end-to-end BPL signal propagation. Third, three interesting findings concerning the statistical properties of MIMO channels of distribution BPL networks are demonstrated, namely, (i) the ACG, RMS-DS, and cumulative capacity lognormal distributions; (ii) the correlation between RMS-DS and ACG; and (iii) the correlation between RMS-DS and CB. By fitting the numerical results, unified regression distributions appropriate for MIMO/BPL channels and systems are proposed. These three fundamental properties can play significant role in the evaluation of recently proposed statistical channel models for various BPL systems. Fourth, the potential of transformation of overhead and underground LV/BPL and MV/BPL distribution grids to an alternative solution to fiber-to-the-building (FTTB) technology is first revealed. By examining the capacity characteristics of various MIMO scheme configurations and by comparing these capacity results against SISO ones, a new promising urban backbone network seems to be born in a smart grid (SG) environment.

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