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Author: thpapad
Type: Document
Downloaded: 124 times
Date: 2017-11-03

MIMO-OFDM Narrowband-PLC in Distribution Systems: Impact of Power Transformers on Achievable Data Rates

Description:
Power-line communication (PLC) is gaining a renewed interest, due to the smart grid (SG) emerging communication requirements. Among other communication technologies, PLC is a very efficient and feasib... see morele solution, especially for the extended SG distribution networks. However, it is very challenging to consider both the medium- and low-voltage parts of the distribution network as a whole communication medium, due to the attenuating effects of distribution transformers, limiting PLC applicability. In this paper, data transmission through distribution transformers is investigated by means of multiple-input multiple-output (MIMO) narrowband power-line communication (NB-PLC) system, utilizing orthogonal frequency-division multiplexing (OFDM) technology. Multi-conductor distribution line and measurement-based transformer models are developed to characterize the MV-LV PLC channel. In addition, OFDM signal processing techniques are applied to enhance the achievable data rates. The transmit power budget and bit allocation across the OFDM sub-channels of the spatial beams are optimized to maximize the data rate through the distribution transformer. The achievable data rates are calculated and systematically analysed for different scenarios to investigate the effects of the distribution lines, connected loads, noise models, etc. Results reveal the superiority of the proposed MIMO design against the traditional SISO systems. In addition, the possibility for an extensive and reliable application of MV-LV PLC communications through distribution transformers is shown.

Tag(s): Distribution lines, distribution transformers, MIMO-OFDM, power-line communication, smart grids

Author: n.sene
Type: Publication
Date: 2015-04-01

Lightning-Induced Overvoltages Transferred Through Distribution Power Transformers

Description:
This paper deals with the calculation of lightning induced overvoltages on medium-voltage (MV) and low-voltage (LV) distribution networks taking into account the presence of MV–LV distribution trans... see moreformers and, in particular, the surge transfer through them. The influence of the high-frequency model adopted for the representation of the power transformer on the calculation results is analyzed, with regards to two different models, both identified and validated by means of laboratory measurements: namely, a simple π of capacitances, and the more complex one introduced by Morched, Marti, and Ottevangers in 1993. Accurate simulation results provide information on the adequacy of both models for the calculations of interest. Additional results, useful to evaluate the expected level of power quality and the benefits achievable by a proper installation of protection devices, are presented making reference to a realistic and complex configuration of an overhead distribution system

Authors: Alberto Borghetti, Atef Morched, Fabio Napolitano, Carlo Alberto Nucci, Mario Paolone,

IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 24, NO. 1, JANUARY 2009

Tag(s): Lightning, distribution transformers, overvolatges