Narrowband Power Research Articles

Characterization of the Potential Effects of EMC Filters for Power Converters on Narrowband Power Line Communications

Electromagnetic Compatibility (EMC) filters are one of the main solutions for dealing with the disturbances generated by power inverters. However, they show series/parallel resonances that introduce variations in the impedance seen from the grid. Consequently, in some cases, these filters have low impedances at resonance frequencies, which can affect Narrowband Power Line Communications (NB-PLC) due to notching effects. For that reason, the potential effects of four EMC filters on NB-PLC have been studied. Laboratory trials in a controlled environment have been carried out, in which the attenuation and the Signal-to-Noise Ratio (SNR) thresholds that define the communication’s quality have been studied. The results presented in this paper show that, although the variations of the channel frequency response are not selective enough to degrade the communication thresholds, the attenuation measured when the filter is connected near the receiver might be sufficiently high to be critical for the communications in some situations. Therefore, EMC filters might have a negative impact on NB-PLC that had not been previously considered.

Formulation and Performance Analysis of Broadband and Narrowband OFDM-Based PLC Systems.

The aim of this paper is to formulate the physical layer of the broadband and narrowband power line communication (PLC) systems described in standards IEEE 1901 and IEEE 1901.2, which address new communication technologies over electrical networks for Smart Grid and Internet of Things applications. Specifically, this paper presents a mathematical formulation by means of matrices of a transmitter and receiver system based on windowed OFDM. The proposed formulation is essential for obtaining the input–output relation, as well as an analysis of the interference present in the system. It is very useful for simulating PLC systems using software designed to operate primarily on whole matrices and arrays, such as Matlab. In addition, it eases the analysis and design of different receiver configurations, simply by modifying or adding a matrix. Since the relevant standards only describe the blocks corresponding to the transmitter, and leave the set-up of the receiver open to the manufacturer, we analysed four different possible schemes that include window functions in different configurations. In simulations, the behaviour of each of these schemes is analysed in terms of bit error and achievable data rates using artificial and real noises.

The broadband power shifts in entorhinal EEG are related to the firing of grid cells

The relationship between the firing of the grid cell and mesoscopic neural oscillations is one of the key issues to understand the neural mechanism of grid cells. Previous studies have focused more on the correspondence between neuronal firing and phases of oscillations, such as phase precession. There are also some conclusions about the relationship between the activity of grid cells and the intensity of neural oscillations, such as the disappearance of grid pattern caused by the blocking of theta rhythm, but the correlation between the firing rates of grid cells and the narrowband power of neural oscillations or the broadband LFP power is still scarce. Through analyzing the records of spike times of grid cells and local entorhinal EEG obtained by Hafting et al., in the spatial navigation experiment, we find that grid cells are, to a large proportion, a kind of broadband-shift neurons, and the positive correlation between grid cell activity and power of low theta and gamma bands was observed. These results have well verified, promoted, and connected many scattered research conclusions, such as the broadband shift phenomenon of hippocampal neurons, the influence of low theta activity on the firing pattern of grid cells, and the positive correlation between single-cell activity and gamma-band activity. This work is of great significance for the study of the neural mechanism of grid cells at the micro and mesoscopic levels, and may also inspire the use of indicators such as broadband power as markers for grid cell activity.

Channel Coding Based on Power Line Communication

This paper focuses on the forward error correction (FEC), the basic parameters determination of the RS convolution code, Turbo code and the LDPC code, and the corresponding encoding and decoding algorithm in power line communication (PLC) standard. Simulation experiment which is designed for narrow-band power line communication system based on OFDM is done. The coding using RS convolution code, Turbo code and LDPC code are compared, and further it is determined that which encoding method is more suitable for power line communication in China.

Construction of Evaluation Index System for the Adaptability of Narrowband Internet of Things and Power Business

With the continuous extension of Smart Grid from the grid side to the user side, the expansion of emerging business is deepening day by day. In terms of terminal access quantity demand of provincial companies, from the original substation of 100 kilo level to the 10 kV distribution system of 100 000 class and the user terminal of 1 million or even 100 million level. Therefore, massive terminal communication is an urgent problem to be solved in power communication network. At present, the State Grid Corporation of China is planning to build terminal communication access network, mainly using optical fiber and Narrow Band Internet of Things wireless technology, mainly to solve the 10kV distribution system; and the communication access of tens of millions or even hundreds of millions of user terminals urgently needs a suitable communication technology to solve. At present, NB-IOT technology has the characteristics of enhanced coverage, ultra-low power consumption, mass access, etc., which can meet the above requirements. This paper mainly describes the construction of NB-IOT technology adaptability evaluation index system, introduces the evaluation method of power narrowband Internet of things, and the evaluation results and analysis of adaptability.

Exploring the reliability and sensitivity of the EEG power spectrum as a biomarker

IntroductionThe slope of the electroencephalography (EEG) power spectrum (also referred to as 1/f noise) is an important consideration when calculating narrow-band power. However, psychophysiological data also suggest this slope is a meaningful signal itself, not merely background activity or noise. We present two different methods for quantifying the slope of the power spectrum and assess their reliability and sensitivity. MethodsWe used data from N = 60 participants who had EEG collected during rest, a videogame task, and a second period of rest. At all phases of the experiment, we calculated the “spectral slope” (a regression-based method fit to all datapoints) and the “aperiodic slope” (estimated with the fitting oscillations with 1/f algorithm FOOOF). For both methods we assessed: their reliability, their sensitivity to the transition from rest to task, their sensitivity to changes during the videogame task itself, and the agreement between the two measures. ResultsAcross resting phases, both spectral and aperiodic slopes showed a high degree of reliability. Both methods also showed a steepening of the power spectrum on-task compared to rest. There was also a high degree of consistency between the two methods in their estimate of the underlying slope, but FOOOF explained more variance in the power spectra across regions and type of activity (rest versus task). ConclusionThe slope of the power spectrum is a highly reliable individual difference and sensitive to within-subject changes across two different methods of estimation. Moving forward, we generally recommend the use of the FOOOF algorithm for its ability to account for narrow-band signals, but these data show how regression-based approaches produce similar estimates of the spectral slope, which may be useful in some applications.

Measurements and characterisation of low and medium voltage residential, commercial, and industrial NB‐PLC networks for AMI

This study investigates the feasibility of advanced metering infrastructure (AMI) based on narrowband power line communications (NB-PLC) by incorporating all possible types of low voltage (LV) and medium voltage (MV) power line channels. The extensive field measurements are carried out on six selected sites that include residential, commercial, and industrial LV and MV NB-PLC channels. On the basis of measured results, NB-PLC channels of various under evaluation sites are segregated into two classes i.e. worst and good channels for both LV and MV networks. The simulation models for the modelling of LV and MV NB-PLC channels by considering the practical data of measured sites are developed and thus proposed. The proposed methods are validated by comparing the measured and simulated results. A sophisticated mechanism for the modelling of LV and MV network impedances and capacitive coupling device is formulated. The proposed analyses and simulation-based NB-PLC channel models can play a key role in examining the characteristics of various types of NB-PLC channels. This research work will help to standardise the future smart metering equipment and sensing devices of power system protection.

Demand Side Management System Characterization for Residential Users in Manizales City

This paper presents the characterization of Demand Side Management System with three constitutive subsystems: i) graphic operation and control interface, ii) communications network through narrow-band power lines (NB-PLC) according to G3-PLC standard, and iii) an array of six photovoltaic solar panels. The LabView graphical interface simulates the system operator and contains the management system control program. The photovoltaic solar generation system was implemented in Manizales city, allowing energy contribution analysis of photovoltaic array with centralized inverter or with microinverters over an 11 months period. Communications system quality tests are presented reaching a Data Transfer Rate of 0.2702 KB/s for a 20.44 meters distance between nodes. Additionally, it is observed that, despite the high levels of precipitation and cloudiness of Manizales city, photovoltaic array with microinverters got a 16.5% gain of generated energy over the energy generated by photovoltaic array with centralized inverter.

Efficient and robust data availability solution for hybrid PLC/RF systems

Recently, many efforts have been made by researchers, standardization organizations, telecommunication industries and energy providers, in order to realize robust and efficient communication in Smart Grids. To meet these requirements, a new generation of Narrow-Band Power Line Communication (NB-PLC) protocols have been proposed. The main advantage of PLC systems is that they require no additional costs in terms of deployment and wiring since the existing power cables can be used to transmit power and data, simultaneously. The PLC technology has many applications within Smart Grids such as advanced metering infrastructure, distributed automation, street light control, and public charging. One popular PLC standard is the Power-line Related Intelligent Metering Evolution (PRIME). This technology enables different types of Smart Grid services over electricity distribution networks. In PRIME, the security is implemented at the data link layer and it targets data confidentiality and message authentication, but not data availability. In this paper, we propose an efficient and robust security solution to guard against availability and confidentiality attacks. The main goal of the proposed solution is to enhance the security and reliability of PLC communication among end nodes with minimum overhead in terms of resources, complexity and latency. The solution is based on the Information Dispersal Algorithm (IDA) and the physical characteristics of PLC channels. In particular, end nodes benefit from a shared working key and the random channel parameters to derive the cryptographic primitives that are used in the proposed scheme. The security and performance tests showed that the proposed solution introduces a low overhead while offering a high degree of availability and reinforcing confidentiality.

Characterization of a Multispectral Imaging System Based on Narrow Bandwidth Power LEDs

Multispectral imaging systems using narrow-band power LEDs have become a feasible solution for a wide range of applications. Their fast response and simple implementation compensate for a low spectral resolution. In this article, we are filling a gap identified in the literature on multispectral systems by presenting a detailed design of a light controller, as well as a characterization of the whole system by means of a correlation and a repeatability analysis. We use a reference color target to assess accuracy and precision by comparing our system with high-performance hyperspectral equipment used in fruit quality control. The system captures multispectral images (MSIs) with 15 different wavelengths ( $\lambda \in [410~950$ ] nm). The main finding is a Pearson correlation index above 80% ( $\rho > 0.8$ ) with a variance in the measure within 10% ( $\sigma ^{2} ). We also examine the characteristics of the instrument at a maximum speed of 8 MSIs/s although this entails sacrificing precision ( $\sigma ^{2} ).

Simpler Than FRESH Filter: A Parametric Approach for Cyclostationary Noise Generation in NB-PLC

A key challenge in narrowband power line communications (NB-PLC) is the mitigation of impairments introduced by the correlated cyclostationary noise. The frequency-shift (FRESH) filtering approach has been recently proposed to reproduce a cyclostationary NB-PLC noise with characteristics similar to those obtained from field measurements. In this letter, we use a classification of the noise generated by the FRESH filter into three classes to propose a simple method to produce noise samples with statistics similar to those obtained at its output. The approach consists of parametrized spectral and temporal shapings applied to a white Gaussian noise sequence. We validate our proposed method by comparing its generated noise samples with those obtained using the FRESH filter and using measurements in terms of: i) normalized mean-squared error between the cyclic auto-correlations; ii) bit error rate.

Investigation of Deterministic, Statistical and Parametric NB-PLC Channel Modeling Techniques for Advanced Metering Infrastructure

This paper is focused on the channel modeling techniques for implementation of narrowband power line communication (NB-PLC) over medium voltage (MV) network for the purpose of advanced metering infrastructure (AMI). Three different types of models, based on deterministic method, statistical method, and network parameters based method are investigated in detail. Transmission line (TL) theory model is used to express the MV network as a two-port network to examine characteristics of sending and receiving NB-PLC signals. Multipath signal propagation model is used to incorporate the effect of multipath signals to determine the NB-PLC transfer function. A Simulink model is proposed which considers the values of MV network to examine the characteristics of NB-PLC signals. Frequency selectivity is also introduced in the impedances to compare variations and characteristics with constant impedances based MV network. A state-of-the-art mechanism for the modeling of capacitive coupling device, and impedances of low voltage (LV) and MV networks is developed. Moreover, a comparative analysis of TL theory and multipath signal propagation models with the proposed Simulink model is presented to validate the performance and accuracy of proposed model. This research work will pave the way to improve the efficiency of next-generation NB-PLC technologies.

A Versatile THz Source from High-Brightness Electron Beams: Generation and Characterization

Ultra-short electron bunches, such as those delivered by a high-brightness photo-injector, are suitable to produce high peak power THz radiation, both broad and narrow band, with sub-picosecond down to femtosecond pulse shaping. The features of this kind of source in the THz range of the electromagnetic spectrum are extremely appealing for frequency- and time-domain experiments in a wide variety of fields. The present manuscript will overview the method of generation and characterization of THz radiation produced by high-brightness electron beams, as those available at the SPARC_LAB test facility.

Interference-Robust Processing of OFDM Radar Signals Using Compressed Sensing

An essential prerequisite for radars in automotive applications, safety systems, future autonomous driving, and industry applications is the reliable operation even under difficult conditions such as interference from other radars. Recently, digital radar principles such as orthogonal frequency division multiplexing (OFDM) have gained increasing attention. In this letter, an interference-robust processing for OFDM radar signals using compressed sensing is presented, which is particularly suitable for random OFDM but also applicable to stepped and standard OFDM. It allows robust radar operation in the presence of interfering signals that have a comparable low instantaneous bandwidth and high narrowband power. The method is validated experimentally using measurements of an OFDM radar setup at 76 GHz and a state-of-the-art FMCW radar as an interferer.

A New Frame Synchronization Algorithm for Linear Periodic Channels With Memory

Identifying the start time of a sequence of symbols received at the receiver, commonly referred to as frame synchronization, is a critical task for achieving good performance in digital communications systems employing time-multiplexed transmission. In this work we focus on frame synchronization for linear channels with memory, in which the channel impulse response is periodic and the additive Gaussian noise is correlated and cyclostationary. Such channels appear in many communications scenarios, including narrowband power line communications and interference-limited wireless communications. We derive frame synchronization algorithms based on simplifications of the optimal likelihood-ratio test, assuming the channel impulse response is unknown at the receiver, which is applicable to many practical scenarios. The computational complexity of each of the derived algorithms is characterized, and a procedure for selecting nearly optimal synchronization sequences is proposed. The algorithms derived in this work achieve better performance than the noncoherent correlation detector, and, in fact, facilitate a controlled tradeoff between complexity and performance.

Generalized Symmetrical 3 dB Power Dividers With Complex Termination Impedances

The paper introduces a class of two-way, 3 dB narrowband power dividers (combiners), closed on complex termination impedances, that generalizes a number of topologies presented during past years as extensions of the traditional Wilkinson design. Adopting even-odd mode analysis, we demonstrate that, under very broad assumptions, any axially symmetric reactive 3-port can be designed to operate as a 3 dB two-way power divider, by connecting a properly designed isolation impedance across two symmetrically but arbitrarily located additional ports. We show that this isolation element can be evaluated by a single input impedance or admittance CAD simulation or measurement; moreover, an explicit expression is given for the isolation impedance. The theory is shown to lead to the same design as for already presented generalizations of the Wilkinson divider; further validation is provided through both simulated and experimental case studies, and an application of the theory to the design of broadband or multi-band couplers is suggested.

More on variance of fatigue damage in non-Gaussian random loadings – effect of skewness and kurtosis

This work investigates the variance of fatigue damage in stationary random loadings with non-Gaussian probability distribution and narrow-band power spectral density. It presents an approach exploiting a non-linear time-invariant transformation that links Gaussian and non-Gaussian domains and that is calibrated on the skewness and kurtosis values of the non-Gaussian process. The transformation allows determining the joint probability distribution of two peaks and the cycle amplitude distribution in the non-Gaussian process, from which the variance of damage is calculated. Monte Carlo numerical simulations are finally discussed to demonstrate the correctness of the proposed model and to investigate the sensitivity of the damage variance to several parameters (S-N inverse slope, skewness and kurtosis of non-Gaussian loading).

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.

Evaluations of Acute and Sub-Acute Biological Effects of Narrowband and Moderate-Band High Power Electromagnetic Waves on Cellular Spheroids

High power electromagnetic signals can disrupt the functioning of electronic devices. As electromagnetism plays a role in cells homeostasis, such electromagnetic signals could potentially also alter some physiological processes. Herein we report on distinct biological parameters assessment after cellular spheroids exposure to high power electromagnetic signals, such as the ones used for defense applications. Signals effects were assessed in tumor cells spheroids and in normal human dermal fibroblasts spheroids, where macroscopic aspect, growth, plasma membrane integrity, induction of apoptosis, ATP content, and mitochondrial potential were investigated after spheroids exposure to high power electromagnetic signals. No significant effects were observed, indicating that 1.5 GHz narrowband electromagnetic fields with incident amplitude level of 40 kV/m, and 150 MHz moderate-band electric fields with an amplitude of 72.5 to approximately 200 kV/m, do not cause any significant alterations of assessed parameters.

Comparison of Measurement Methods of LV Grid Access Impedance in the Frequency Range Assigned to Nb‑Plc Technologies

The paper presents and evaluates three advanced methods for the characterization of the low-voltage (LV) grid access impedance for the frequency range assigned to Narrow Band-Power Line Communications (NB-PLC): 9 kHz to 500 kHz. This study responds to the recent demand from both regulatory bodies and Distribution System Operators about the need for accurate and validated methods for this frequency band, due to the limited knowledge of the impedance values in the electrical grid and their influence on NB-PLC transmission channels. In this paper, the results of a collaborative work to develop different proposals to overcome the challenges for the proper characterization of the frequency and time-varying grid impedance, from different theoretical approaches, are presented. The methods are compared in a controlled and isolated scenario: the impedance characterization of passive filters. Then, the results are validated two-fold: first, against theoretical simulations, based on the schematics provided by the manufacturer, and second, against the measurement results of a precision impedance meter, used as a reference of accuracy. The results demonstrate a high degree of precision of the three proposals to characterize the access impedance of the LV grid.