宽带电力线通信技术应用浅谈

就电力线宽带接入网络的原理、优势进行了阐述。对宽带电力线通信（PLC）技术的国内外发展现状及存在的问题与争议进行了分析,并对宽带电力线通信技术的应用提出了一些建议。     

基于DSP电力线通信调制解调器的设计与实现

简要介绍了宽带电力线通信技术,选择OFDM作为宽带电力线通信中的调制技术.对OFDM的参数进行设计和芯片选择,介绍了TMS320VC5409的功能特点和结构,并以该处理器为核心,同时采用TLC876、AC101LKQT等外围芯片,开发了低压配电网的宽带电力线通信Modem.该Modem可应用于配电网.     

面向智能电网的电力线宽带通信性能测试

电力线宽带通信是实现电网与电信网、广播电视网、互联网有机融合的有效手段,是支撑智能电网用户侧交互功能的重要技术方向.文章搭建了一个面向智能电网的电力线宽带通信性能测试平台,通过一个视频点播系统来对电力线宽带通信性能进行评估,验证了电力线宽带通信设备对"多网融合"视频点播等服务的支撑能力,分析了影响数据可靠传输的主要因素...     

电力线宽带网络技术及应用

介绍了电力线宽带网络技术,详细阐述了电力线宽带网络技术的关键技术及原理,阐明了扩频通信SSC技术和正交频分复用OFDM技术及其在电力线通信技术上的应用,分析了电力线通讯技术特点及其存在问题,最后给出了电力线通信技术在家庭联网上的应用及其实现方案。     

智能电网电力线宽带通信性能研究

电力线宽带通信已成为承载智能电网应用的最重要的通信技术之一,特别针对高级量测系统和家庭局域网,应用尤为广泛.目前绝大多数电力线宽带通信产品都基于正交频分复用、离散多频调制或扩频技术,这些技术在不同场景下的通信性能各异.文章为电力线通信设备提出了性能测试模型,用于评测其传输容量和噪声容限.基于该模型,测试了4种使用不同调制技术的电力线通信设备,进一步分析不同调制技术的性能测试结果并取得一定结论.为减小电气设备引入噪声对通信的影响,文章提出“隔离插座”,用于滤除电器侧噪声.     

正交频分复用前置编码技术在宽带电力线通信中的应用

基于正交频分复用(OFDM)的概念,提出在宽带电力线通信(PLC)中应用前置编码改进常用编码OFDM的新技术;在分析常用编码OFDM技术应用于宽带电力线通信时存在的缺点的基础上,给出了具体的前置编码方案;还在实际低压电力载波通道模型上对这两种技术进行了宽带电力线通信模拟仿真实验,仿真结果表明,应用前置编码OFDM技术可显著减小传输信号的误码率,并可简化基于常用编码OFDM技术的通信系统实现的复杂性.     

低压电力集抄上行通信信号盲区解决方案研究

为解决用电信息采集设备因安装在移动信号盲区,而导致GPRS/CDMA模块通信无法上线的问题,文中介绍了一种基于宽带载波通信技术的无线信号中继器设备——宽带电力线载波无线信号中继器。宽带电力线载波无线信号中继器由数据转换单元、本地单元和远程单元组成,本地单元与远程单元间通过宽带电力线载波通信技术进行通信。在使用原有终端与GPRS/CDMA远程通信模块的条件下,加装宽带电力线载波无线信号中继器,可使信号不良区域的终端实现与主站实时数据交互。通过试验测试表明,宽带电力线载波无线信号中继器具有良好的通信实时性和可靠性,能够较好地满足低压电力集抄系统上行通信对于通信技术的需求。     

宽带电力线认知通信系统OFDMA子载波分配研究

随着配电设备数量不断增加,宽带电力线载波频谱资源渐显匮乏。文章认为,引入认知频谱的概念组成宽带电力线认知通信系统,可在电力线衰落的信道上侦测其他配电设备不用或没有充分利用的频率,采用正交频分多址技术进行通信,并提出一种基于分布式宽带电力线认知通信系统的子载波分配方案,仿真结果表明了所提算法的有效性和优势。     

基于电力线宽带载波集中器设计与中继算法

针对国内目前低压电力线抄表系统中采用的窄带载波集中器及人工中继路由方式,提出了基于电力线宽带载波的集中器设计方案及自动中继路由算法.宽带载波集中器硬件是以S3C2440为核心,采用电力线宽带载波技术与采集器通信、通用分组无线服务(GPRS)技术与管理中心通信;软件是基于嵌入式Linux操作系统设计,采用多路I/0复用技...     

电力线宽带通信信道特征分析

电力线宽带通信技术具有较多优势,但是低压电力线信道特性极为复杂,导致通信效果不能良好稳定。关于电力线宽带通信的可靠性和快速性的研究仍在发展当中,由于各国电网环境的差异较大,目前为止国际上尚未能形成统一的技术标准。我国的电力线信道特性也与国外不同,特别是早年对电网布线优化度重视不足及对电器质量要求较低,使得某些地区的信道条件相对恶劣。因此,低压电力线信道特性的合理检测和分析,对于我国电力线宽带通信标准的制定,调制解调器的研制及应用、电力线通信算法的仿真和改进来说,是非常有意义的。     

An Experimental Validation for Broadband Power-Line Communication (BPLC) Model

Recently, different models have been proposed for analyzing the broadband power-line communication (BPLC) systems based on transmission-line (TL) theory. In this paper, we make an attempt to validate one such BPLC model with laboratory experiments by comparing the channel transfer functions. A good agreement between the BPLC model based on TL theory and experiments are found for channel frequencies up to about 100 MHz. This work with controlled experiments for appropriate validation could motivate the application and extension of TL theory-based BPLC models for the analysis of either indoor or low-voltage or medium-voltage channels.     

Power-Line Communication Channel Model for Interconnected Networks—Part II: Multiconductor System

In this paper, we present an approach to determine the transfer function for multiconductor power-line networks with distributed branches and load terminations for broadband power-line communication (BPLC) applications. The applicability of the proposed channel model is verified numerically in time domain using the finite-difference-time domain (FDTD) method for the solution of transmission lines. The channel model simulation results are in excellent agreement with the corresponding FDTD results. The model therefore could be useful in the analysis and design of BPLC systems involving multiconductor power-line topology.      

Expressions for Current/Voltage Distribution in Broadband Power-Line Communication Networks Involving Branches

Estimation of electromagnetic (EM)-fleld emissions from broadband power-line communication systems (BPLC) is necessary, because at its operating frequencies, the radiated emissions from BPLC systems act as sources of interference/crosstalk to other radio-communication systems. Currently, the transmission-line (TL) system used for BPLC is complex, involving arbitrarily/irregularly distributed branched networks, arbitrary termination loads, varying line lengths, and line characteristic impedance. In order to study the electromagnetic-compatibility (EMC) issues associated with the radiated emissions of such complex BPLC networks, knowledge of current and voltage distributions along the length of the power-line channels is needed. This paper attempts to derive and present generalized expressions for either the current or voltage distribution along the line (whose TL parameters are known) between the transmitting and receiving ends for any line boundary condition and configuration based on the TL theory. The expressions presented in this paper could be beneficial for direct calculation of EM emissions from BPLC systems.     

网络参数对低压宽带电力线信道的影响

在电力线载波信道的研究中,目前有关电网结构对电力线载波性能的影响研究较少,多径效应和频率选择性衰落现象难以从现有模型得到合理解释,也对电力线节点间的通信性能和路径拓扑中继理论支持不足,制约了宽带电力线载波通信性能的提升。针对此,通过使用基于传输线理论的方法对低压电力线通信信道仿真建模,分析了不同网络拓扑结构对频率为2~30MHz的低压宽带电力线信道特性的影响。仿真得到不同电力线长度、分支长度、单节点分支数、分布式分支数和负载阻抗的低压宽带电力线信道频率响应,并通过反傅里叶变换得到对应的信道时域冲激响应。结果表明,电力线信道频率响应中的峰值点和陷波频点的位置和衰减会受到上述网络参数的影响,时域冲激响应也会因此而衰减和失真。本文的研究对于宽带电力线通信技术在能源互联网中的有效应用具有重要意义。     

Performance of Underground Cables That Use OFDM Systems for Broadband Power-Line Communications

Power-line networks are proposed for broadband data transmission. The presence of multipaths within the broadband power-line communication (BPLC) system, due to stochastic changes in the network load impedances, branches, etc. pose a real challenge as it affects network performance. This paper attempts to investigate the performance of an orthogonal frequency-division multiplexing (OFDM)-based BPLC system that uses underground cables. It is found that when a branch is added in the link between the sending and receiving end, there is an average of 4-dB power loss. In addition, when the terminal impedances of the branches that are connected to the link between the transmitting and receiving end vary from line characteristic impedance to low-impedance values, the power loss (signal-to-noise ratio) is about 0.35 dB/ Omega. On the contrary, for an increase in the terminal impedances by 100 Omega above line characteristic impedance, the power loss is 0.23 dB//Omega. When the branch terminal impedances are close to short or open circuits, OFDM techniques show degraded performance. This situation is also observed when the number of branches increases. It is shown that to overcome degraded network performance, the concatenated Reed-Solomon codes/interleaved Viterbi methods can be used, which could be used for an efficient design of the BPLC system that uses OFDM techniques.     

On the Efficacy of Using Ground Return in the Broadband Power-Line Communications—A Transmission-Line Analysis

The power-line infrastructure has been identified as an efficient system suitable for broadband power-line communication (BPLC) to connect and control various end users. However, the network is affected by stochastic attenuations due to the number of interconnected branches, their line lengths, associated terminal loads, etc. There is yet another parameter that could influence the above stated attenuations or distortions depending on the way the signals are allowed to return to the transmitting end. In this paper, we investigate whether a finitely conducting ground return could be used for BPLC and to investigate its performance over the conventional methods where one of the adjacent power-line conductors is used as signal return. This study could be helpful to those who are proposing the use of ground as a return conductor in BPLC systems. It will be shown that the use of ground return for the BPLC system is effective or better only when the ground conductivity is high (>50 mS/m). When ground conditions are poorer, attenuations increase with frequency, making them unsuitable for BPLC. There are situations where poor ground conditions can still be used but only the transmission-line lengths are shorter. The analysis presented here is based on transmission-line solutions both under lossless (without ground return) and lossy (with ground return) conditions and are applied to typical low-voltage and medium-voltage channels. Comparisons are also made based on the power spectral densities and channel capacities.     

The Influence of Load Impedance, Line Length, and Branches on Underground Cable Power-Line Communications (PLC) Systems

An underground cable power transmission system is widely used in urban low-voltage power distribution systems. In order to assess the performance of such distribution systems as a low-voltage broadband power-line communication (BPLC) channel, this paper investigates the effects of load impedance, line length, and branches on such systems, with special emphasis on power-line networks found in Tanzania. From the frequency response of the transfer function (ratio of the received and transmitted signals), it is seen that the position of notches and peaks in the magnitude are largely affected (observed in time-domain responses too) by the aforementioned network configuration and parameters. Additionally, channel capacity for such PLC channels for various conditions is investigated. The observations presented in this paper could be helpful as a suitable design of the PLC systems for better data transfer and system performance.     

The Effects of Load Impedance, Line Length, and Branches in the BPLC—Transmission-Line Analysis for Indoor Voltage Channel

This paper presents the effects of load impedance, line length and branches on the performance of an indoor voltage broadband power line communications (BPLC) network. The power line network topology adopted here is similar to that of the system found in Tanzania. Different investigations with regard to network load impedances, direct line length from transmitter to receiver, branched line length, and number of branches has been carried out. From the frequency response of the transfer function (ratio of the received and transmitted signal), it is seen that position of notches and peaks in the magnitude and phase responses are largely affected by the above said network parameters/configuration, mainly in terms of attenuation and dispersion. These effects are observed in the time domain responses also. The observations presented in the paper could be helpful in the suitable design of the BPLC systems for a better data transfer and system performance.