Low-voltage power line channel environment and the application analysis in smart grid

In view of the existence of manual meter reading various drawbacks, and achieving the remote monitoring, analysis and management of energy consumption, we present a practical application system: An Online Electric Energy Data Acquisition and Monitoring System. The system consists of intelligent data acquisition terminal and management platform. The intelligent data acquisition terminal gets data through Power Line Carrier or RS-485 from electric energy meter which is named downlink communication and uplink communication with the remote management platform by GPRS channel. Downlink communication uses “DL/T645-2007Multi-function watt-hour meter communication protocol”, and uplink communication protocol is the “Q/GDW1376.1 — 2012 power user electric energy data acquisition system communication protocol”. Both of the two protocols are in line with national standards which can ensure a good compatibility with electric energy meter product by different companies. To ensure high real time performance, a strictly time control mechanism for per meter reading and dynamic data storage management mode have been designed. Besides, a reasonable reconnection mechanism and an heartbeat frame between acquisition terminal and management platform is necessary to achieve high on-line performance.

The popularity of the Power Line Communication (PLC) system has decreased due to significant deficiencies in the technology itself, even though new wire installation is not required. In particular, regarding the request for high-speed throughput to fulfill smart-grid requirements, Broadband Power Line (BPLC) can be considered. This paper approaches PLC technology as an object of simulation experimentation in the Broadband Power Line Communication (BPLC) area. Several experimental measurements in a real environment are also given. This paper demonstrates these experimental simulation results as potential mechanisms for creating a complex simulation tool for various PLC technologies focusing on communication with end devices such as sensors and meters. The aim is to demonstrate the potential and limits of BPLC technology for implementation in Smart Grids or Smart Metering applications.

The paper presents a methodology proposal for testing and evaluation of communication systems in Smart Grids, especially for Power Line Communication (PLC) systems. The PLC technology is widely used in power grid as a part of Advanced Metering Infrastructure (AMI) allowing mainly data transfers between a management system at utility and customer-premises smart meters. However, the PLC technology on medium voltage (MV) lines is often used for remote control and monitoring of distribution transformers as well. Since power grid and consequently power lines have different transmission parameters affected by their placement and potentially burdened by interferences, the PLC systems have to be evaluated on site before placed to production. In this paper, authors propose a methodology for long-term benchmarking of the PLC systems using newly developed testing tools. The methodology is subsequently tested on real power grid and a selection of results is presented.

After more than two decades since intensive research began on power line communications (PLC) technology, this interesting field of telecommunication engineering is still progressing towards maturity. Despite some factors that delay its worldwide acceptance, its implementation is starting to take off. Research in PLC is motivated (i) by many factors such as the crowded radio frequency spectrum that requires to be sustained by alternative technologies and (ii) by the emanation of other new technologies that may help PLC to extend its practical implementation such as visible light communications or other wireless communication technologies like near‐field communications. PLC technology is used in applications requiring both low and high data rate but traditionally exploited in applications in which the node does not move. Nowadays, PLC has become widely accepted; hence, a review of the technology may be useful to keep the readers aware of new updates. In this paper, we provide an overview of the evolution of PLC technology over the last few decades.

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

Power Line Communications (PLC) is regarded as the promising home networking technology for smart grid application since the PLC technology enables data transmission via the existing power line. The cooperation between PLC and Wireless Local Area Network (WLAN) will be an effective hybrid solution for Home Area Networks (HANs). In this paper, we consider that Transmission Control Protocol (TCP) packets are transmitting in heterogenous communications network based on PLC and WLAN. The existing TCP congestion control has low effectiveness due to the error-prone power line channel. Therefore, we propose an adaptive rate control to improve TCP performance in the hybrid PLC/WLAN HANs. We exploit the communications mechanism of WLAN to improve the PLC link utilization. The methodology of Heuristic Dynamic Programming (HDP) is employed to obtain the optimal rate policy. The bottleneck link capacity is estimated by neural network training. The sending rate is adapted according to the long-term quality of service (QoS) of applications. Simulation results illustrate that the proposed rate control effectively filters out the negative impact from the instantaneous impulse noise in PLC channel and outperforms the existing TCP.

Security of Power Line Communication systems: Issues, limitations and existing solutions

Power line communication (PLC) technology has proved itself in the last decade as an interesting solution for data transmission and communication in domestic application. Lately, this technology has been considered as a potential solution for monitoring and diagnosis of a motor-fed inverter setup. Information issued from sensors would be sent via power cables back to the controller despite the harsh environment and the switching of the inverter. This paper discusses the use of PLC technology over a pulsewidth modulation network by underlining the effect of the power cable length and the inverter switching on communication. A new approach based on the measurement of scattering parameters is used for this purpose, and the effect of the cable length is analyzed. It is shown that, for long distances, the PLC technology may not be effective, and hence, it is not possible to use power cables for communication.

The Data communication over the Transmission line can be done through Smart Grid using Power Line Communication (PLC). The Power Line Communication technology is considered as economic and reliable source of communication technology. It became more convenient and prominent for standalone Renewable Energy Systems (RES) which are remotely located. Smart grid's metering and monitoring process are done through PLC. In this Paper a system is proposed with 8-PSK communication technology. It will modulate the data with 3-Phase transmission line at the generation side and demodulate it at the grid side to get the information. So by this system power, voltage, current and physical change of the environment or Generation device is successfully monitored. This system could be also used at user side and grid side to detect the available load. Here Photovoltaic Cell (PV) is adopted as a Renewable Energy Source, boost converter and IGBT inverter to analyze the system. By this proposed system we could eliminate the additional monitoring cost instead of Ethernet based or SCADA system which is being used in recent time.

In recent years, the vulnerability attack on the industrial control system appears more organized and diverse. In this paper, we focus on power user electric energy data acquisition system and its communication protocol, namely 376.1 master station communication protocol. The system is an important infrastructure in national economy and people’s livelihood. To efficiently discover abnormal behaviors during its communication, we propose a terminal access data anomaly detection model based on gradient boosting decision tree (GBDT). Firstly, through analyzing the characteristics of the communication protocol and different kinds of terminal access data, we construct a high-quality multidimensional feature set. Then we choose GBDT as the abnormal access data detection model. The experimental result shows that the detection model has a high detection accuracy and outperforms its counterparts.

Modern hospitals are beginning to adopt E-HEALTH as efficient complements to the traditional healthcare services. To support the E-HEALTH services, a locatable, radiation-free and high-capacity communication system is urgently needed in hospitals. Power line communication (PLC) system can use the ubiquitous power line network to power the light-emitting diode (LED) lights while serving as the backbone network for the indoor visible light communication (VLC) systems naturally. In this paper, an integrated broadband power line and visible light communication systems with OFDM modulation is proposed for the indoor hospital applications. This gives a brand-new solution to replace the conventional wireless communication systems in hospitals.

Broadband PLC (power line communication) has become one of the most important communication technologies for Smart Gird applications, especially for AMI (Advanced Metering Infrastructure) and HAN (Home Area Network). Currently, most broadband PLC products are based on OFDM, DMT or Spread-Spectrum technologies. Their performances differ from each other on certain circumstances. This paper proposes a performance testing model to test PLC devices' Transmitting Capacity and Noise Tolerance. Four PLC devices using different modulation technologies respectively are tested. In addition, the performances of different technologies are analyzed and some discussions are made. To reduce the affection of noise brought in by electric appliances, an "isolating socket" is introduced, which can filter the noises on the appliance side.

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.

Power line communication is a critical component of smart grids, which are vulnerable to eavesdropping. To address this challenge, we investigate a cooperative relay hybrid power line and wireless communication system where multiple eavesdroppers are considered. We propose an elaborate artificial noise (AN)-aided beamforming (BF) scheme to improve physical layer security. Our scheme maximizes the outage-constrained secrecy rate (OCSR) of the legitimate link while restricting the capacity of the eavesdroppers to a reasonable region. However, due to the imperfect channel state information of the wiretap channel and secrecy outage probability constraint, the robust OCSR problem becomes intractable because of the non-concave secrecy objective function and the non-convex constraints. To solve this issue, we utilize semidefinite programming and Bernstein-type inequality to transform the robust OCSR nonconvex problem into two convex sub-problems, which a block-coordinated descent algorithm can solve. Simulation results showcase the effectiveness of our robust AN-aided secure BF scheme and show that the proposed scheme outperforms the benchmark scheme in a security performance gain under various channel conditions, even in the worst case.

This keynote discusses the behavior of noise in indoor power line communications (PLC) channels. Some ideas to improve system performance based on the knowledge of PLC noise are also introduced. The power-line noise at an outlet is the sum of noise waveforms produced and emitted to the lines from the appliances connected to the power-line network. In the design and the analysis of wireless communication systems, stationary additive white Gaussian noise (AWGN) is often assumed. In PLC systems, however, the statistical behavior of the man-made noise is quite different from that of the stationary AWGN. The fact that the noise in power-lines is not AWGN is often believed to be a cause of low quality of communications. However, Gaussian is the distribution of the largest entropy, and communications under non-Gaussian noise may achieve better performance if the system is designed to adapt the noise statistics. In other words, PLC systems retain large potential for performance improvement if the behavior of the noise is clarified and taken into account in the system design. For narrow-band indoor PLC, we have a mathematically tractable and accurate model based on experimental measurements. In this model, the noise is expressed as a Gaussian process whose instantaneous variance is a periodic time function. With this assumption and representation, the cyclostationary features of power-line noise can be described in close form formula with a small set of parameters. In wide-band indoor PLC, we have made measurements with high speed sampling (50MHz) with long observation duration (10.4s).