Towards Broadband Over Power Lines Systems Integration: Transmission Characteristics of Underground Low-Voltage Distribution Power Lines

Abstract

Abstract-A complete methodology is employed to determine the transmission characteristics of low-voltage/broadband over power lines (LV/BPL) channels associated with underground power distribution networks, in the light of the multiconductor transmission line (MTL) theory. The established bottom-up approach, already used to treat overhead and underground MV/BPL transmission, is extended to analyze BPL transmission in three-phase N -conductor underground lines with common shield and armor. This analysis shows that these cables may support N + 2 modes, giving rise to N + 2 separate transmission channels which reduce to N +1 if the armor either does not exist or is grounded and to N if the shield is also grounded. In addition to the generalized analysis, a simplified approximation concerning three-phase N -conductor underground cables is also presented. Taking the generalized analysis and the simplified approximation into account, their numerical results concerning attenuation in various underground LV/BPL channels in the frequency range 1-100 MHz are validated against relevant sets of simulations and measurements with satisfactory accuracy and compared to corresponding results of overhead and underground MV/BPL channels. It has been verified that the attenuation in overhead and underground BPL channels depends drastically on power distribution grid type, MTL configuration, and cables used. Moreover, the attenuation in underground LV/BPL channels exhibits a lowpass behavior, is significantly higher than that of overhead MV/BPL ones, and is comparable to that of underground MV/BPL ones. A consequence of the proposed methodology is that it

Review and Progress towards the Common Broadband Management of High-Voltage Transmission Grids: Model Expansion and Comparative Modal Analysis

“…Based on [3,36,42,43], in this paper, a top-down approach is proposed to determine the end-to-end attenuation of overhead HV/BPL channels based on an exact version of multidimensional chain scattering matrix or T-Matrix method. This novel extended chain scattering matrix or TMatrix (TM2) method, which is already well verified in the case of overhead and underground LV/BPL and MV/BPL distribution power grids [3], combines the accuracy of the generic multidimensional network analysis tool presented in [3,36,42,43] and the simplicity of hybrid model of [1][2][3][21][22][23][24][25]. Based on numerical results concerning various simulated overhead HV/BPL topologies, BPL transmission via the overhead transmission power grid is investigated aiming at clarifying the influence of factors, such as the overhead HV power grid type (150 kV, 275 kV, or 400 kV and single or double circuit), the physical properties of the cables used, the MTL configuration, the end-to-end distance, and the number, the length, the terminations, and the multiplicity of the branches encountered along the endto-end BPL signal propagation.…”

“…Since the overhead power grid was not originally designed to serve the purpose of a transmission medium for communication signals, the overhead transmission power grids are subjected to attenuation, multipath due to various reflections, noise, and electromagnetic interference [1][2][3][21][22][23][24][25][26][27][28][29][30][31]. Each of the aforementioned adverse factors affects critically the overall performance and the design of BPL systems [32][33][34][35].…”

“…As usually done in BPL transmission, a hybrid model is employed to examine the behavior of BPL transmission channels installed on BPL multiconductor transmission line (MTL) structures [1,2,[21][22][23][24][25][36][37][38][39][40][41]. Through a bottom-up approach consisting of an appropriate combination of the similarity transformation and MTL theory, the modes that may be supported by an overhead HV/BPL configuration are determined concerning their propagation constants and their characteristic impedances [1-3, 21-25, 35-47].…”

Main Line Fault Localization Methodology (MLFLM) in Smart Grid – The Underground Medium- and Low-Voltage Broadband over Power Lines Networks Case

“…With reference to Fig. 2, average path lengths of the order of 200m are considered in UN MV and UN LV topologies [6], [7], [11], [12]. In fact, the definition of a maximum path length in UN BPL networks prevents high channel attenuations that may eliminate the broadband potential of BPL networks.…”

“…According to [6], [11], [12], [16], by comparing channel attenuations of UN distribution BPL channels, it is evident that the channel attenuation of UN MV BPL channels is significantly higher than the one of UN LV BPL channels. This channel attenuation difference is primarily due to the insulation characteristics of the considered UN MV cables -i.e., paper-insulated lead covered (PILC) distribution cables-.…”