Modelo de canal para caracterizar la señal dispersada por un parque eólico en la banda UHF e influencia sobre la calidad de servicio de DVB-T

288 p. : il.[ES]La presencia de un parque eólico provoca una serie de efectos sobre las señales electromagnéticas que pueden dar lugar a una degradación de la calidad de los servicios de telecomunicaciones proporcionados en sus cercanías. En lo que respecta a la difusión de televisión, el efecto de un parque eólico en la difusión de televisión digital no había sido determinado hasta ahora.Por otra parte, la evaluación de la posible degradación de estos servicios se ha realizado tradicionalmente mediante modelos que caracterizan la señal dispersada por las aspas del aerogenerador. Estos modelos clásicos de dispersión no contemplan ni la contribución del mástil a la señal dispersada, ni la variabilidad temporal de la señal dispersada debida a la rotación de las palas, ni la influencia conjunta de un parque eólico compuesto por varias máquinas.En este contexto, se plantea el primero de los objetivos principales de esta tesis: la evaluación empírica de la degradación causada en la recepción de señales de televisión digital DVB-T debida a la presencia de un parque eólico. Del estudio realizado, basado en medidas de campo, se concluye que las condiciones de recepción más críticas se dan en la zona de backscattering, donde la propagación responde a las características de un canal multitrayecto discreto variante con el tiempo.El segundo objetivo principal de esta tesis se centra en la propuesta un nuevo modelo de canal para caracterizar la propagación multitrayecto típica en los alrededores de un parque eólico en esta banda. Este modelo de canal se adapta a las condiciones particulares de cada caso en estudio: posición relativa transmisor-turbina-receptor, dimensiones del aerogenerador, velocidad máxima de rotación de las aspas, características de los sistemas radiantes del transmisor y receptor, y frecuencia de trabajo.[EN]The presence of a wind farm causes several effects on the electromagnetic signals that may degrade the quality of the telecommunication services provided nearby. In regard to television broadcasting, these effects are notable for the analogue signal. However, a potential impact of a wind farm on digital television broadcasting had not yet been assessed. Apart from that, the evaluation of the potential degradation on these services has been traditionally carried out by means of scattering models that only account for the signal scattered by the blades of a wind turbine. These classic models do not consider neither the mast contribution to the scattered signal nor the time variability due to the blade rotation or the joint influence of a wind farm composed of several turbines. In this context, the first of the two main objectives of this thesis is the empirical evaluation of the degradation caused to the DVB‐T digital television signals reception due to the presence of a nearby wind farm. From this measurement‐based study, it can be concluded that it is in the backscattering region where the most critical reception conditions are encountered. In this zone, the propagation channel can be characterized by a discrete time‐varying multipath channel. Therefore, in order to determine future possible degradations on the services provided in the UHF band, the second main objective of this thesis focuses on proposing a new channel model to characterize the multipath propagation typical of the area surrounding a wind farm. This channel model is adaptable to the particular features of each case under study: relative position transmitter‐wind turbine‐receiver, wind turbine dimensions, maximum rotation rate, characteristics of the transmitter and receiver radiating systems, and working frequency. In this way, the results obtained in this research work give answer to the studies requested by the International Telecommunications Union since the first cases of impact were detected[EUS]Parke eolikoek hainbat efektu eragiten dute seinale elektromagnetikoetan eta, ondorioz, zenbait kasutan, inguruan eskaintzen diren telekomunikazio zerbitzuek kalitatearen degradazioa jasan dezakete. Telebistari dagokionez, efektu hauek nabarmenak dira seinale analogikoaren kasuan. Aitzitik, parke eolikoek telebista digitalean izan dezaketen eragina ez da oraindik zehaztu. Bestalde, oraindaino telebista zerbitzuek izandako inpaktuaren ebaluazioa sakabanatze-ereduen bidez egin da. Sakabanatze-eredu klasiko hauek palek sakabanatzen duten seinalea baino ez dute adierazten; eta horrenbestez, ez dute kontuan hartzen dorreak sakabanatzen duen seinalea, ez besoen errotazio mugimenduak eragindako denbora aldakortasuna, ezta hainbat aerosorgailuz osatutako parkearen eragin bateratua ere. Testuinguru honetan, ikerkuntza lan honen lehen helburu nagusia definitzen da: parke eoliko batek DVB-T sisteman eragin dezakeen harrera-degradazioaren ebaluazio enpirikoa egitea. Neurketetan oinarritutako analisi honetatik, harrerabaldintza zailenak backsckattering delako eremuan gertatzen direla ondorioztatzen da, non hedapenak Ibilbide anitzeko eredua jarraitzen duen. Eredu honen portaera denborarekin aldakorra izango da palen errotazio mugimenduaren ondorioz. Horrez gain, UHF bandan igorritako zerbitzuetan gerta daitezkeen degradazioak aurreikusi ahal izateko, tesiaren bigarren helburua zehazten da: parke eoliko baten inguruan sortutako hedapen tipikoa deskribatzen duen kanal eredu berria proposatzea. Kanal eredu hau aztergai dauden kasu guztien baldintza partikularretara moldatzen da, eta kontuan hartzen du, besteak beste: transmisore-turbina-hargailu arteko kokapen erlatiboa, aerosorgailuaren tamaina, palen errotazio gehienezko abiadura, transmisore eta hargailuaren antenen ezaugarriak, eta frekuentzia. Tesi honetan lortutako emaitzei esker, lehenengo kasuak antzeman zirenetik Telekomunikazioen Nazioarteko Batasunak proposatutako ikerketa eskariei erantzuna ematen zaie.Tesis financiada con beca del Programa de Formación de Personal Investigador del Departamento de Educación, Universidades e Investigación (BFI08.230) del Gobierno Vasco. Colaboración del Communications Research Centre (CRC) de Canadá a través del Dr. Yiyan Wu, Adivic Technology co., Abertis Telecom, Itelazpi y Eólicas de Euskadi (hoy Iberdrola Renovables

Virtual PLC Lab Enabled Physical Layer Improvement Proposals for PRIME and G3-PLC Standards

Narrowband (NB) powerline communication (PLC) is extensively adopted by utilities for the communication in advanced metering infrastructure (AMI) systems. PLC technology needs to overcome channel disturbances present in certain grid segments. This study analyzes improvement proposals of the physical layer of the main narrowband PLC technologies approved by international communication organizations that are currently deployed in Europe: Powerline Intelligent Metering Evolution (PRIME) 1.3.6, PRIME 1.4, and G3-PLC, in order to improve PLC performance under channel disturbances. This thorough study is based on simulations carried out by an innovative ad hoc Virtual PLC Lab, developed by the authors, applied in replicable, fully-automated, and cost reduced test scenarios. The analysis is performed by applying standardized test methods and metrics, and by evaluating the influence of a set of representative channel disturbances defined by the European Telecommunications Standards Institute (ETSI) and selected noises generated by distributed energy resources (DER) in normal operation. PLC performance improvements in terms of equalizer curve fitting, error correction codes, and noisy subcarrier suppression mechanisms are presented. The performance gain due to each physical improvement proposal is accurately measured and compared under the same conditions in a replicable and automated test environment in order to evaluate the use of the proposals in the evolution of future PLC technologies.This work was financially supported in part by the Basque Government under the grant numbers Elkartek KK-2018/00037 and IT1234-19, and by the Spanish Government under the grant RTI2018-099162-B-I00 (MCIU/AEI/FEDER, UE)

Impact of Channel Disturbances on Current Narrowband Power Line Communications and Lessons to Be Learnt for the Future Technologies

[EN] The electricity network is a complex communication medium with properties that depend on both the topology of the grid and the usage pattern of the connected devices. These devices generate channel disturbances during normal operation, which need to be overcome by power line communications (PLC) transmission technologies for ensuring communication. This paper analyzes the influence of the channel disturbances on the performance of the physical layer of the main narrowband PLC technologies approved by international communication organisms and currently deployed in Europe: PoweRline Intelligent Metering Evolution (PRIME) 1.3.6, PRIME 1.4 and G3-PLC. The methodology of this paper applies a standardized test method, metrics and a set of representative channel disturbances defined by the European Telecommunications Standards Institute (ETSI). Moreover, noise recordings from field measurements in an environment equipped with distributed energy resources (DER) complete the subset of the types of noise used in the study. This paper develops a replicable, fully automated, and cost optimized test scenario, based on an innovative Virtual PLC Laboratory, which provides a replicable and automated test process, where a wide range of channel disturbances can be accurately replicated, and the performance of the PLC technologies can be compared under the same conditions. The results of this paper provide important conclusions to be applied in the development of future PLC technologie

State of the Art and Trends Review of Smart Metering in Electricity Grids

Climate change, awareness of energy efficiency, new trends in electricity markets, the obsolescence of the actual electricity model, and the gradual conversion of consumers to prosumer profiles are the main agents of progressive change in electricity systems towards the Smart Grid paradigm. The introduction of multiple distributed generation and storage resources, with a strong involvement of renewable energies, exposes the necessity of advanced metering or Smart Metering systems, able to manage and control those distributed resources. Due to the heterogeneity of the Smart Metering systems and the specific features of each grid, it is easy to find in the related literature a wide range of solutions with different features. This work describes the key elements in a Smart Metering system and compiles the most employed technologies and standards as well as their main features. Since Smart Metering systems can perform jointly with other activities, these growing initiatives are also addressed. Finally, a revision of the main trends in Smart Metering uses and deployments worldwide is included.his work has been partially supported by the Spanish Ministry of Economy and Competitiveness (project TEC2015-67868-C3-1-R), the University of the Basque Country (UPV/EHU) within the program for the specialization of the postdoctoral researcher staff, and Microgrids with Renewable Distributed Generation (MIGEDIR) (project 713RT0468), funded by the Science and Technology for Development Iberoamerican Program (CYTED)

Planning Large Single Frequency Networks for DVB-T2

[EN] The final coverage and associated performance of an SFN is a joint result of the properties of all transmitters in the SFN. Due to the large number of parameters involved in the process, finding the right configuration is quite complex. The purpose of the paper is to find optimal SFN network configurations for DVB-T2. Offering more options of system parameters than its predecessor DVB-T, DVB-T2 allows large SFN networks. However, self-interference in SFNs gives rise to restrictions on the maximum inter-transmitter distance and the network size. In order to make optimum use of the spectrum, the same frequency can be reused over different geographical areas - beyond the reuse distance to avoid co-channel interference. In this paper, a methodology based on theoretical network models is proposed. A number of network architectures and network reference models are considered here for different reception modes in order to study the effects of key planning factors on the maximum SFN size and minimum reuse distance. The results show that maximum bitrate, network size and reuse distance are closely related. In addition, it has been found that the guard interval is not the only limiting parameter and that its impact strongly depends on the rest of DVB-T2 mode parameters as well as on the network characteristics (Equivalent Radiated Power, effective height, inter-transmitter distance). Assuming that the C/N requirements are in the vicinity of 20 dB and bitrates over 30 Mbps, it has been found that the network can be as large as 360 x 360 km (delivering 39.2 Mbps) or even 720 x 720 km (delivering 37.5 Mbps). The reuse distance will also have a complex dependency on the DVB-T2 mode and especially the network parameters, ranging from below 100 to 300 km.This work has been financially supported by the Beihang University, IRT, the University of the Basque Country UPV/EHU (UFI 11/30 and program for the specialization of the postdoctoral researcher staff) and by the Spanish Ministry of Economy and Competitiveness under the project HEDYT-GBB (TEC2012-33302)

Large size FFTs over time-varying channels

[EN] In orthogonal frequency division multiplexing (OFDM) signals, the usage of large size fast Fourier transforms (FFTs) reduces the guard interval percentage, and therefore increases the data throughput reducing the data overhead. In addition, for the same pilot pattern, the distance between adjacent pilots is smaller, which will improve the channel estimation. Nevertheless, up to now, they have not been considered for delivering mobile services as the inter-carrier interference (ICI) due to the Doppler effect is very critical. The main objective is to show that taking advantage of the latest improvements in error correction techniques, it is feasible to use large size FFTs for time-varying channels. Furthermore, there is also presented a theoretical estimation for quantifying the loss due to the ICI, and finally several simulation results that reinforce the idea that large OFDM symbols are suitable for mobile channels.This work has been financially supported in part by the University of the Basque Country UPV/EHU (UFI 11/30), by the Basque Government (IT-683–13 and SAIOTEK), by the Spanish Ministry of Science and Innovation under the project NG-RADIATE (TEC2009-14201), and by the Spanish Ministry of Economy and Competitiveness under the project HEDYT-GBB (TEC2012-33302)

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.This research was funded by the BASQUE GOVERNMENT, grant number IT1234-19 and SPANISH GOVERNMENT, grant number RTI2018-099162-B-I00 (MCIU/AEI/FEDER-UE)

Smart Grid Applications for a Practical Implementation of IP over Narrowband Power Line Communications

Abstract Currently, Advanced Metering Infrastructure (AMI) systems have equipped the low voltage section with a communication system that is being used mainly for metering purposes, but it can be further employed for additional applications related to the Smart Grid (SG) concept. This paper explores the potential applications beyond metering of the available channel in a Power Line Communication-based AMI system. To that end, IP has been implemented over Narrow Band-Power Line Communication (NB-PLC) in a real microgrid, which includes an AMI system. A thorough review of potential applications for the SG that might be implemented for this representative case is included in order to provide a realistic analysis of the potentiality of NB-PLC beyond smart metering. The results demonstrate that existing AMI systems based on NB-PLC have the capacity to implement additional applications such as remote commands or status signals, which entails an added value for deployed AMI systems.This work has been partially funded by the Basque Government (IT.683-13 and ELKARTEK KK-2017/00071

On-field evaluation of the performance of IP-based data transmission over narrowband PLC for smart grid applications

[EN] One of the current efforts for the grid modernization is the deployment of Advanced Metering Infrastructure systems. Regarding AMI technologies, NarrowBand PLC is one of the most spread technologies worldwide. While current AMI deployments based on NB-PLC focus on metering applications, this work addresses the operation of IP over NB-PLC for Smart Grid applications. IP is a well-established standard that might become the key enabler for the interoperability amongst numerous applications for the Smart Grid. In this scenario, on-field measurements become essential to test the coexistence of AMI systems and data transmission beyond metering applications. This paper analyses the configurations and parameters that affect the performance of IP over PRIME such as the number of nodes in the subnetwork, switching levels and transport layer protocols, among others. Results show that the topology of the subnetwork plays a key role for the resulting data rates and provide a meaningful contribution towards the implementation of new applications over NB-PLC based on IP data transmission

A new voltage probe with improved performance at the 10 kHz–500 kHz frequency range for field measurements in LV networks

[EN] Voltage measurements in the frequency range from 10 kHz to 500 kHz are used to quantify the level of the Narrow Band Power Line Communication transmitted signals, the noise and the non-intentional conducted emissions generated by the devices connected to the Low Voltage grid. Considering that the voltage levels within this frequency range are very small if compared to measurements below 2 kHz, measuring equipment of higher precision is needed, but existing standards do not currently cover this frequency band. In this paper, a voltage adapter with improved performance at the 10 kHz–500 kHz frequency range for field measurements in LV networks is presented. Moreover, a measurement setup and methodology for the frequency-dependent characterization of this type of voltage adapters is described, which is used to demonstrate the outperformance of the designed probe with respect to four commercial devices.This work has been financially supported in part by the Basque Government (Elkartek program and IT-683-13)