Power Line Communication Communication Research Articles

Characterizing Low-Data-Rate Power Line Communication Channels

Electric power lines could, in principle, provide a ubiquitous wired communication network linking electrical loads, power meters, and other devices. This communication infrastructure could unlock new sensing and control capabilities, improving the efficiency and reliability of power system operations. In practice, however, power line communication (PLC) is complicated by both known and variable difficulties related to background noise, signal attenuation, and unknown line impedances. This article develops instrumentation that characterizes and verifies line characteristics for PLC applications, especially for demand response and control applications. This instrumentation provides a window to key variables that affect communication on a local power distribution network. With these measurements, limits on PLC communication can be verified before an installation, and a PLC system may also be adaptively tuned to measurements of the current local environment. Field experiments in a challenging microgrid and a 24-floor apartment building demonstrate an appropriately tailored PLC system communicating reliably in locations where conventional PLC fails.

Sources of Non-Intentional Supraharmonics in LV Network and Its Impact on OSGP PLC Communication – Experimental Study

The article presents the cross-sectional results of analyzes of authentic conducted disturbances introduced into public power networks by various types of loads installed at end users. The foundation for the research was a set of 260 identified cases of Power Line Communication (PLC) transmission disturbances based on the Open Smart Grid Protocol (OSGP) technology, which were recorded in the urban network of the distribution system operator covering over 400,000 smart meters. The paper presents a quantitative assessment of the share of loads that most often cause problems with transmission efficiency. Moreover, a qualitative assessment of the detected disturbance cases was carried out in terms of conditions relating to the structure of the power grid and real transmission levels and disturbance levels. The authors made a pioneering analysis in the so-called “communication path” where the PLC communication disturbance was identified, i.e., from the installation point of the PLC concentrator to the metering point where the energy meter, with which the connection was lost, was installed.

Zero-Additional-Hardware Power Line Communication for DC–DC Converters

A power line communication (PLC) solution to provide a data link between two or more dc–dc power converters is proposed. The approach does not require additional analog circuitry or high-sample-rate analog-to-digital converters to be added on top of the original system. A modulation and signal injection method for the transmitter, and a sampling and demodulation strategy for the receiver are developed. The PLC frequency band is placed between the control loop cutoff frequency and the power electronics circuit cutoff frequency, in a region that we identify as the “intermediate frequency band”. The transmitter modulates the converter voltage or current output by injecting perturbations into the control loop at the input to the PWM unit. To tolerate unsynchronized transmitter and receiver clocks, a virtual zero-crossing location algorithm is combined with long/short pulse identification to achieve demodulation at the receiver. The solution is verified experimentally and achieves reliable bidirectional PLC communication at 2 kb/s with an 8 kHz receiver sampling frequency.

Impact of Li-Ion Battery on System's Overall Impedance and Received Signal Strength for Power Line Communication (PLC).

In anticipation of the hybrid utilisation of the radio frequency (RF) wireless transceiver technology embedded in future smart Li-ion battery cells to deliver hybrid links based on power line communication (PLC) and wireless connections, herein we present an empirical high-frequency investigation of the direct current (DC) bus. The focus is to determine, via statistical tools including correlation coefficient (CC), root mean squared error (RMSE) and feature selective validation (FSV) method, the impedance and signal change impact on a possible communication link when fully charged cells are present or completely missing from the bus. Moreover, to establish if technological differences may be accounted for during the empirical experiments, Li-ion cells from two different manufacturers were selected and connected via three subsequent capacitive couplings of 1 µF, 1 nF and 1 pF. According to a methodical comparison by employing CC, RMSE, and FSV over the measured impedance and signal attenuation, this study has shown that the physical DC network is the dominant impedance at high frequencies and that the signal attenuation on the DC line supports communication in the investigated spectrum. The reported findings are critical for in situ hybrid PLC and wireless communication implementation of BMS for Li-ion systems supported through only one RF transceiver.

Communication Distance Estimation for Power Line Communication Using Various Differently Constituted Power Cables

The use of PLC (power line communication) is growing as the adoption of IoT technology becomes more widespread. However, the maximum communication distance between PLC modems cannot yet be clearly defined since the communication characteristics of the power lines used for PLC are not formally specified. In this paper, the propagation characteristics in the high‐speed PLC communication band of 2–30 MHz were investigated when equipment is not connected to the power line except both ends. The line constants for five typical types of cables used as single‐phase and two‐wire power lines were measured. Our results showed that different cables have markedly different transmission characteristics. The attenuation constant varied up to fourfold depending on the cable insulator material. We also derived a method of estimating the communication distance for different cables for application of the HD‐PLC system, which is the most commonly used type of high‐speed PLC. The measurement result by using VCT cable was almost agreed with the estimated value. By comparing the estimated distance with the experimental results, we show that the transmission distance can be estimated with sufficient accuracy for practical use. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Deterministic vs. Random Modulated Interference on G3 Power Line Communication

Power line communication (PLC), which is often used in advanced metering infrastructure (AMI), may be disturbed by adjacent high-power converters. Due to the inherent features of this type of communication, classic methods of improving communication reliability (filtration and circuit separation) cannot be fully applied. Information coding (modulation) methods are used in PLC to increase the data transfer rate and improve noise immunity. Random modulations (RanM) are used in converters to lower emission levels. Therefore, we investigate how the converters’ modulation parameters and coding methods may affect PLC communication reliability in the paper. To this end, we employ an experimental approach. In particular, the analysis of the influence of deterministic modulation (DetM) and (RanM) on the performance of narrowband G3-PLC is shown. We emulated an actual situation where EMI generated by the DC/DC converter disturbed the PLC transmission. The experimental results show the transmission error rates for different operating scenarios. The natural (experimental) system results, due to the complexity of the disturbing signals, differ from the literature data obtained by simulation for normalized signals.

The Impact of Supply Voltage Waveform Distortion on Non-Intentional Emission in the Frequency Range 2–150 kHz: An Experimental Study with Power-Line Communication and Selected End-User Equipment

Knowledge of the conducted emissions in the frequency range 2–150 kHz contains some gaps related to the impact of the harmonics in the supply voltage on the nature of these emissions. It can be noticed that the conducted emissions from non-sinusoidal power supplies have not been studied sufficiently, and that the impact of this distortion may be greater than the generally known results of emission tests carried out under standardized test conditions. This paper is aimed at investigating experimental cases of the influence of supply voltage waveform distortion on non-intentional emission in the range 2–150 kHz and the efficiency of power line communication based on selected PRIME (PoweRline Intelligent Metering Evolution) power line communication (PLC) technology. A series of experimental laboratory studies were investigated, representing the operation of the investigated PLC system with different types of end-user equipment (LED—Light Emitting Diode, CFL—Compact Fluorescent Lamp, induction motor with frequency converter) working under a distorted supply voltage condition obtained by the programmable power supply for different scenarios of the admissible harmonics contribution in the range 0–2 kHz. The scenarios included limits defined in standards EN 50160 and IEC 61000-4-13. The researchers used spectral analysis with a notation to emission limits, compatibility levels, and mains signalling, as well as statistics of the PLC communication. The obtained results provide important conclusions, which may be applied both in the development of the design of the appliances in question and the higher frequency emission testing methods.

A Dual-mode Communication Power Internet of Things Routing Algorithm Based on RPL Protocol

Medium frequency (less than 12 MHz) Power Line Communication (PLC) and micro-power wireless Radio Frequency (RF) communication dual-mode communication technology can realize the depth and breadth coverage of the power Internet of Things (IoT) and enhance the robustness of the network. But dual-mode communication also brings difficulties to the application of the RPL protocol. According to the characteristics of PLC and RF dual-mode communication technology, the routing communication delay is the optimization objective function, and a routing metric algorithm of RPL routing protocol is proposed. The RPL protocol is applied to the dual-mode communication in power Internet of Things. Experiments show that the proposed algorithm has higher communication efficiency and can meet the needs of dual-mode communication hybrid networking and operation. It is a feasible method.

Narrow Band Power Line Communication (NB-PLC) frequency band review under residential load noise

Advanced Metering Infrastructure (AMI) is the foundation of the Smart Grid system. One of the most important parts of AMI is smart meter communication. Power Line Communication (PLC) technology utilizes the existing power line network for communication media between smart meters and Data Collector Units (DCU). One of the biggest challenges of communication using PLC is the noise level due to residential loads. In this study, laboratory test set up to measure noise caused by PV rooftop and residential loads are observed. Each PLC frequency band was measured and observed to determine the suitable frequency for PLC communication which was the low noise level. Some experiments in the field were conducted to determine the performance of the PLC. Laboratory test measurement result shows the FCC band (150-490 kHz) was outside the range of PV rooftop and residential load noise. On the other hand, the Cenelec A (35-90 kHz) frequency range was in the range of noise signal. Therefore, NB-PLC G3 using FCC frequency band was proposed to achieve robust data communication and lower noise level. G3 PLC FCC band was tested in the real field residential area, the experimental results showed 97.62% successful rate within one-week data collection.

Optimised PLC transmission over pulse‐width modulated network

In industrial application of adjustable speed drive for electrical motors, some sensors are supplying mandatory information such as speed or position of the rotor to the electronic command. In most deployed applications, these data are transmitted through an additional dedicated line. In order to avoid this additional installation, power line communication (PLC) technology can be used. This study proposes a PLC communication solution between an inverter and a motor through a variable length cable. This solution relies on the modelling of this communication channel as well as the characterisation of the pulse-width modulated signal. The communication parameters such as carrier frequency or modulation format (quadrature phase shift keying etc.) have been optimised to reduce the channel-to-noise ratio in this context. An error free 2 Mbit/s communication has been achieved on a 2 kW test bench.

Simulation of Achievable Data Rates of Broadband Power Line Communication for Smart Metering

Building real Smart Metering and Smart Grid networks is very expensive and time-consuming and also it is impossible to install different technologies in the same environment only for comparison. Therefore, simulation and experimental pilot measurements are an easy, economical, and time-affordable solution for a first comparison and evaluation of different technologies and solutions. The local area networks (LAN) are the core of Smart Metering and Smart Grid networks. The two predominant technologies are mostly sufficient for LAN networks, Power Line Communication (PLC), and radio frequency (RF) solutions. For PLC it is hard to allow prediction of the behaviour. Performance assessment for point-to-point connection is easy, but for complex PLC networks with repeaters it is quite expensive. Therefore, a simulation is an easy, fast, and cheap solution for understanding the grid configuration, influence of particular topological components, and performance possibilities. Simulation results can, thus, provide material for the design of a telecommunication infrastructure for Smart Metering. This paper presents results of such a simulation study. It is based on realistic PLC channel model implementation in Network Simulator 3, our modification and extension of this implementation for our use case scenario. It uses Shannon’s formula to calculate theoretical maximum channel capacity. In particular, it provides channel capacity and achievable distances of broadband PLC (BB-PLC). In this article we also exploit our novel idea of simple performance assessment of broadband PLC communication via simulation. It is supposed to be used to understand, evaluate, and test the grid configuration before deployment.

High Data Rate Discrete Wavelet Transform-Based PLC-VLC Design for 5G Communication Systems

The hybrid power line communication (PLC) and visible light communication (VLC) systems can be effectively utilized for the efficient design of 5G communication setup. However, each of these integrated communication media is not primarily meant for the specific purpose of data communication, as PLC and VLC have historically served to transfer electrical energy transfer and light, respectively. With the advent of high flickering rate light emitting diodes and efficient multiplexing/modulation schemes, both technologies are observed as potential data communication carriers. Therefore, this paper presents a novel approach for modifying the modulation technique in accordance with the channel requirements of a hybrid PLC-VLC-based 5G communication systems. We provide a thorough analysis of the research work done to co-use these two technologies for data communication, suggest some exciting applications of integrated PLC-VLC systems and propose discrete wavelet transform (DWT)-based orthogonal frequency division multiplexing (OFDM) to tune the physical parameters as per the hybrid channel characteristics. Theoretical and simulation bit-error-rate results exhibit that DWT-OFDM outperforms an OFDM-based PLC-VLC system. The proposed hybrid system can be used to design smart buildings where indoor/intra-building connectivity is maintained by VLC whereas inter-building networking based on PLC communication.

Design and experimental characterization of a combined WPT–PLC system

In this contribution, the authors perform the design and show the experimental results relative to a prototype of a combined wireless power transfer (WPT)–power line communications (PLC) system, in which the WPT channel is interfaced to a PLC environment to allow data transfer when the cabled connection is no longer available. The main rationale behind this idea stays in the fact that PLC communication is now a popular choice to enable communications, for instance, in smart grids and in home automation, while WPT devices start to be available in the market (i.e. for mobile phones) and soon they will be a reality also for higher power (i.e. vehicle battery charging). In particular, theoretical insights about the requirements of the system are given; a two coils system has been implemented and a measurement campaign, together with simulations, show that the system is of great potentiality and could be used in applications where both wireless power and data transfer are needed (such as vehicles battery charging), achieving maximum power transfer and good data rate in order to transmit high-speed signals.

Evaluation of communication network state estimators for adaptive power-balancing

Smart grid applications are going to reach the low voltage grid assets and households in order to efficiently use the resources in electrical distribution grids. A cost effective way to connect these devices is to utilize the existing network infrastructure or Power-Line Communication (PLC). In this work, we illustrate the impact of changing communication properties on a power balancing controller used to support frequency control in the setting of a microgrid. More specifically, we focus on PLC communication and show how time-varying delays can affect the control algorithm performance. Further, we propose and compare two different delay estimation techniques and demonstrate how the control algorithm can use this information to adapt its gains - yielding significantly better control performance, compared to the controller using static gains.

Oil-Filled MV/LV Power-Transformer Behavior in Narrow-Band Power-Line Communication Systems

The aim of this paper is to characterize oil-filled power transformers in the narrow-band power-line communication (PLC) frequency range of 50–150 kHz. A new model is proposed for such type of a transformer, in the aforementioned frequency range of interest, in order to study its influence on the signal transmission and to investigate the possibility that the PLC signal can cross the power transformer itself. The new model is simpler than those previously proposed in literature, and it can be used in the whole frequency range available for NB PLC according to the CENELEC EN 50065-1 A-band. In order to validate the model, simulation and measurement results are compared for four oil-filled power transformers with different rated power values. A complete PLC system in the case of a medium-voltage (MV) power network is also simulated, in order to perform a preliminary evaluation of the influence of power transformers on the communication system. The MV overhead power line, the oil-filled power transformers, the MV signal coupling network, and two ST7540 frequency shift keying (FSK) power-line transceivers are included in the simulated system. The performances of the complete PLC communication system are evaluated in the case of both MV to low voltage (LV) and LV to MV transmissions. The analysis is carried out by evaluating the signal attenuation, which is computed as the ratio between the received and transmitted voltage signals, in the case of different line lengths and carrier frequency values.

Compromising Radiated Emission from a Power Line Communication Cable

This contribution presents a preliminary investigation on the possibility of eavesdropping, i.e., of extracting information by exploiting the electromagnetic field radiated in the vicinity of a power line communication (PLC) network. This kind of problem is usually known in the electromagnetic compatibility area under the codename TEMPEST. Electromagnetic field measurements were carried out in a laboratory environment, both inside and outside a building, and the main statistical characteristics of the compromising channel are presented. A software tool simulating a PLC communication has been developed and used to draw apreliminary conclusion on whether the radiated emissions can be exploited or not.

Review of Channel Characterization for Power Line Communications

The power line communication (PLC) channel has been a transmission medium that enables to transfer high-speed digital data through the classical electrical wires. Channel characteristics of power lines are very important for communications systems design. In order to get the suitable model for power line communications analysis and improve the PLC communication quality, researchers do lots of study about the PLC channel characterizations based on actual measurement and theoretical analysis. This paper reviews the conclusions of recent studies, summaries the characteristics of PLC channel for medium voltage power lines and low voltage power lines. The further research is also put forward.

Home Network Power-Line Communication Signal Processing Based on Wavelet Packet Analysis

Recent advances in signal processing methodologies have spawned the way for a high-speed home network power-line communication (PLC) system. In this paper, a novel signal processing method based on wavelet packet analysis is proposed to combat the adverse communication environment over power lines. A comparison research between wavelet transform and wavelet packet transform is presented. Since wavelet packet decomposition can provide more precise frequency resolution than wavelet decomposition, this paper proposes to use the wavelet packet analysis to deal with the highly polluted PLC communication signal. A hardware structure for the PLC system is presented as an experimental platform for sampling an actual communication signal. Simulation results based on these kinds of actual communication signals show the effectiveness of the proposed method.