Medium-voltage/broadband Over Power Lines Research Articles

Smart Energy and Spectral Efficiency (SE) of Distribution Broadband over Power Lines (BPL) Networks – Part 2: L1PMA, L2WPMA and L2CXCV for SE against Measurement Differences in Overhead Medium-Voltage BPL Networks

This second paper assesses the performance of piecewise monotonic data approximations, such as L1PMA, L2WPMA and L2CXCV, against the measurement differences during the spectral efficiency (SE) calculations in overhead medium-voltage broadband over power lines (OV MV BPL) networks. In this case study paper, the performance of the aforementioned three already known piecewise monotonic data approximations, which are considered as countermeasure techniques against measurement differences, is here extended during the SE computations. The indicative BPL topologies of the first paper are again considered while the 3-30 MHz frequency band of the BPL operation is assumed. Citation: Lazaropoulos, A. G. (2018). Smart Energy and Spectral Efficiency (SE) of Distribution Broadband over Power Lines (BPL) Networks – Part 2: L1PMA, L2WPMA and L2CXCV for SE against Measurement Differences in Overhead Medium-Voltage BPL Networks. Trends in Renewable Energy, 4, 185-212. DOI: 10.17737/tre.2018.4.2.0077

Main Line Fault Localization Methodology in Smart Grid – Part 1: Extended TM2 Method for the Overhead Medium-Voltage Broadband over Power Lines Networks Case

These three papers cover the overall methodology for the identification and localization of faults that occur in main transmission and distribution lines when broadband over power lines (BPL) networks are deployed across the transmission and distribution power grids, respectively. In fact, this fault case is the only one that cannot be handled by the combined operation of Topology Identification Methodology (TIM) and Instability Identification Methodology (FIIM). After the phase of identification of main distribution line faults, which is presented in this paper, the main line fault localization methodology (MLFLM) is applied in order to localize the faults in overhead medium-voltage BPL (OV MV BPL) networks. The main contribution of this paper, which is focused on the identification of the main distribution line faults, is the presentation of TM2 method extension through the adoption of coupling reflection coefficients. Extended TM2 method is analyzed in order to identify a main distribution line fault regardless of its nature (i.e., short- or open-circuit termination). The behavior of the extended TM2 method is assessed in terms of the main line fault nature and, then, its results are compared against the respective ones during the normal operation, which are given by the original TM2 method, when different main distribution line fault scenarios occur. Extended TM2 method acts as the introductory phase (fault identification) of MLFLM.

Designing Broadband over Power Lines Networks Using the Techno-Economic Pedagogical (TEP) Method – Part II: Overhead Low-Voltage and Medium-Voltage Channels and Their Modal Transmission Characteristics

Based on the techno-economic pedagogical (TEP) method proposed in [1] that is suitable for designing Broadband over Power Lines (BPL) networks in transmission and distribution power grids, this paper examines the broadband potential of overhead low-voltage/broadband over power lines (LV/BPL) and medium-voltage/broadband over power lines (MV/BPL) networks. In this paper, on the basis of the set of linear simplifications and techno-economic metrics already presented in [1], TEP method demonstrates to undergraduate electrical and computer engineering (ECE) students the behavior of overhead LV/BPL and MV/BPL networks in terms of their modal transmission characteristics when different overhead LV/BPL and MV/BPL topologies occur. The contribution of this paper is four-fold. First, the factors influencing modal transmission characteristics of overhead LV/BPL and MV/BPL networks are investigated with regard to their spectral behavior and end-to-end channel attenuation. Second, the impact of the multiplicity of branches at the same junction is first examined. In the light of cascaded two-way power dividers, TEP method is extended so as to cope with more complex BPL topologies offering a new simplified and accurate circuital approximation. Third, apart from the broadband transmission characteristics of the entire overhead distribution power grid, a consequence of the application of TEP method is that it helps towards the intraoperability/interoperability of overhead LV/BPL and MV/BPL systems under a common PHY framework in the concept of a unified distribution smart grid (SG) power network. Fourth, TEP method can be demonstrated to undergraduate ECE students as case study in order to stimulate their interest for Microwave Engineering and Circuit/System Engineering courses. Citation: Lazaropoulos, A. (2015). Designing Broadband over Power Lines Networks Using the Techno-Economic Pedagogical (TEP) Method – Part II: Overhead Low-Voltage and Medium-Voltage Channels and Their Modal Transmission Characteristics. Trends In Renewable Energy, 1 (2), 59-86. doi: 10.17737/tre.2015.1.2.006

Underground distribution BPL connections with (N + 1)-hop repeater systems: A novel capacity mitigation technique

This review paper considers the broadband potential of underground low-voltage/broadband over power lines (LV/BPL) and medium-voltage/broadband over power lines (MV/BPL) connections when N repeaters are additively deployed between their existing transmitting and receiving ends (underground LV/BPL and MV/BPL connections with (N+1)-hop repeater system).The contribution of this paper is threefold. First, the broadband performance of a great number of underground LV/BPL and MV/BPL connections with (N+1)-hop repeater system has been studied with regard to capacity and the proposed metric of capacity outage probability (COP). The analysis and relevant simulations validate the significant capacity improvement in comparison with existing underground LV/BPL and MV/BPL systems when multiple repeaters are installed across them. Second, it is found that the underground BPL network capacity performance depends drastically on factors such as the electromagnetic interference (EMI) limits and the deployment of multiple-input multiple-output (MIMO) systems across the underground BPL connections. Adopting (N+1)-hop repeater systems, capacity losses due to: (i) existing strict EMI limits; and (ii) avoidance of MIMO/LV/BPL and MIMO/MV/BPL systems deployment; can be reduced. Third, the numerical simulations reveal the importance of considering as a suitable countermeasure technique against potential capacity discrepancies the installation of (N+1)-hop repeater system across the existing underground BPL connections. This capacity mitigation technique can significantly improve the capacity performance of existing LV/BPL and MV/BPL installations when strict EMI limits or disregard of MIMO system installations inhibit imminent BPL network expansion.

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

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.

Review and Progress towards the Capacity Boost of Overhead and Underground Medium-Voltage and Low-Voltage Broadband over Power Lines Networks: Cooperative Communications through Two- and Three-Hop Repeater Systems

This paper reviews and analyzes the broadband capacity and the coexistence potential of overhead and underground medium-voltage/broadband over power lines (MV/BPL) and low-voltage/broadband over power lines (LV/BPL) topologies when one and two repeaters are additively deployed between their existing transmitting and receiving ends (overhead and underground MV/BPL and LV/BPL topologies with two- and three-hop repeater system, respectively). The contribution of this paper is four fold. First, the factors that influence the broadband capacity performance of overhead and underground MV/BPL and LV/BPL topologies with multihop repeater systems are identified, namely the number of repeaters, the distribution power grid type—either overhead or underground, either MV or LV, the initial distribution BPL topology, the multiconductor transmission line configuration, and coupling scheme applied. Second, the well-validated applicability of two-hop repeater systems is now extended in overhead and underground LV/BPL and MV/BPL networks. The significant mitigating role of two-hop repeater systems against capacity losses due to aggravated topologies or different coupling schemes is verified. Third, the deployment upgrade of two- to three-hop repeater systems in distribution BPL topologies is first examined in terms of broadband capacity performance. To study the occurred capacity improvement, suitable capacity contour plots are first proposed. Fourth, multi-hop repeater systems are identified as valuable technology solution so that the required intraoperability between overhead and underground MV/BPL and LV/BPL networks, which is a prerequisite condition before BPL systems symbiosis with other broadband technologies (interoperability), is promoted.

Green overhead and underground multiple-input multiple-output medium voltage broadband over power lines networks: energy-efficient power control

The broadband potential of overhead and underground medium-voltage/broadband over power lines (MV/BPL) systems associated with multiple-input multiple-output (MIMO) transmission technology and energy efficient (EE) or green policies is examined analytically. The contribution of this paper is threefold. First, various overhead and underground MIMO/MV/BPL topologies have been studied with regard to appropriate transmission measures and spectral efficient (SE)/EE metrics such as channel attenuation, subchannel efficiency, EE subchannel efficiency, capacity, EE capacity, and power consumption. It is found that the above metrics depend drastically on the frequency, power constraints imposed to suppress electromagnetic interference (EMI) to other services, EE policies adopted to regulate power consumption, power grid type (either overhead or underground), MIMO scheme properties, MTL configuration, the physical properties of the cables used, and other topological characteristics. Second, further insights regarding the transmission and SE/EE capacity properties of various MIMO/MV/BPL systems reveal the similar behavior among single-input multiple-output, multiple-input single-output, and single-input single-output MV/BPL systems due to specific MIMO/MV/BPL channel characteristics. Third, using suitable SE/EE metrics, significant trade-off curves between capacity performance and power consumption described through dynamic quasiconcave curves are disclosed. The definition of proper injected power spectral density mask limits combined with the use of continuous/adaptive EE policies provide both EMI protection and EE-oriented high-bitrate MIMO/MV/BPL system design aiding towards sustainable BPL technology satisfying both Quality of Service requirements and ecological awareness (green technology initiatives).

Towards Modal Integration of Overhead and Underground Low-Voltage and Medium-Voltage Power Line Communication Channels in the Smart Grid Landscape: Model Expansion, Broadband Signal Transmission Characteristics, and Statistical Performance Metrics (Invited Paper)

The established statistical analysis, already used to treat overhead transmission power grid networks, is now implemented to examine the factors influencing modal transmission characteristics and modal statistical performance metrics of overhead and underground low-voltage/broadband over power lines (LV/BPL) and medium-voltage/broadband over power lines (MV/BPL) channels associated with power distribution in smart grid (SG) networks. The novelty of this paper is threefold. First, a refined multidimensional chain scattering matrix (TM2) method suitable for overhead and underground LV/BPL and MV/BPL modal channels is evaluated against other relative theoretical and experimental proven models. Second, applying TM2 method, the end-to-end modal channel attenuation of various LV/BPL and MV/BPL multiconductor transmission line (MTL) configurations is determined. The LV/BPL and MV/BPL transmission channels are investigated with regard to their spectral behavior and their end-to-end modal channel attenuation. It is found that the above features depend drastically on the frequency, the type of power grid, the mode considered, 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, the statistical properties of various overhead and underground LV/BPL and MV/BPL modal channels are investigated revealing the correlation between end-to-end modal channel attenuation and modal root-mean-square delay spread (RMS-DS). Already verified in the case of overhead high-voltage (HV) BPL systems, this fundamental property of several wireline systems is also modally validated against relevant sets of field measurements, numerical results, and recently proposed statistical channel models for various overhead and underground LV/BPL and MV/BPL channels. Based on this common inherent attribute of either transmission or distribution BPL networks, new unified regression trend line is proposed giving a further boost towards BPL system intraoperability. A consequence of this paper is that it aids in gaining a better understanding of the range and coverage that BPL solutions can achieve; a preliminary step toward the system symbiosis between BPL systems and other broadband technologies in an SG environment.

Broadband Transmission via Underground Medium-Voltage Power Lines—Part II: Capacity

The end-to-end transfer function of three-phase underground medium-voltage broadband over power-lines (MV/BPL) cables with common shield and armor is determined based on a new exact version of the chain scattering matrix method. The various topologies of the underground MV grid are studied with regard to the spectral behavior of the end-to-end attenuation and to the respective capacity and are compared to the corresponding overhead cases. The numerical results reveal that broadband transmission via underground MV power lines depends drastically on the type of cables used and the topology of the underground MV grid. Also, the relaxed power injection limits and the lower noise power levels characterizing underground MV/BPL transmission counteract the extremely high inherent attenuation, making the capacity achieved compatible to that achieved in overhead MV/BPL transmission.

Capacity of Overhead Medium Voltage Power Line Communication Channels

This paper considers broadband transmission via the overhead medium voltage (MV) grid. The MV broadband over power lines (MV/BPL) channels considered are three-phase overhead MV lines above lossy plane ground. To determine the end-to-end transfer function of any MV/BPL configuration the scattering matrix method is adopted. Various topologies of MV/BPL transmission channels have been studied with regard to their end-to-end signal attenuation and capacity. The analysis and relevant simulations reveal that broadband transmission via MV power lines depends drastically on the MV grid topology and the power constraints imposed to suppress electromagnetic interference to other services. A modification to the fixed spectrum allocation/all-protection model to regulate BPL emission is proposed employing power masks adaptive to locally existing wireless services.