Field Trials for the Characterization of Non-Intentional Emissions at Low-Voltage Grid in the Frequency Range Assigned to NB-PLC Technologies

The paper describes the results of a measurement campaign to characterize the non-intentional emissions (NIE) that are present in the low voltage section of the electrical grid, within the frequency range assigned to narrowband power line communications (NB-PLC), from 20 kHz to 500 kHz. These NIE may severely degrade the quality of the communications and, in some cases, even isolate the transmission devices. For this reason, the identification and characterization of these perturbations are important aspects for the proper performance of the smart grid services based on PLC. The proper characterization of NIE in this frequency range is a key aspect for the selection of efficient configurations to find the best trade-off between data throughput and robustness, or even for the definition of new improved error detection and correction methods. The huge number of types of NIE, together with the wide variety of grid topologies and loads distribution (density and location of homes and industrial facilities) are great challenges that complicate the thorough characterization of NIE. This work contributes with results from field trials in different scenarios, the identification of different types of NIE and the characterization both in time and frequency domains of all the registered disturbances. This contribution will be helpful for a better knowledge of the electrical grid as a transmission medium for PLC and, therefore, for evaluating the appropriateness of different robustness techniques to be applied in the next generation of smart grid services.This work was funded in part by the Basque Government under the grants IT1234-19 and Elkartek KK-2018/00037 and the Spanish Government under the grant RTI2018-099162-B-I00 (MCIU/AEI/FEDER-UE)

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

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

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)

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)

A comparative study of the field strength prediction methods in the MW band

[EN] The recently developed digital radio systems for the MW band require accurate field strength prediction algorithms for coverage estimation. This paper presents a comparison of the estimation accuracy provided by the most relevant field strength prediction methods employed for ground-wave propagation at this band. Moreover, a field strength prediction method recently developed by the authors, has been also considered in the analysis. Empirical values from measurement campaigns carried out in three different broadcasting networks have been used to analyse the accuracy of the prediction methods. The comparison between the predicted and the measured values allows an objective evaluation of the estimation accuracy of each method under different reception conditions. The proposed method provides the most accurate results on field strength predictions, and consequently, it is a suitable method for the coverage estimation of the new digital radio systems

A Measurement-based Multipath Channel Model for Signal Propagation in Presence of Wind Farms in the UHF Band

[EN] Scattering signals on wind turbines may lead to degradation problems on the communication systems provided in the UHF band, such as terrestrial television broadcasting, broadband wireless systems or public safety services. To date, despite the continuous requests from the International Telecommunication Union for studies on this field, no channel model has been developed to characterize signal propagation under these particular conditions. In response to this necessity, this paper presents a complete Tapped Delay Line (TDL) channel model to characterize multipath propagation in presence of a wind farm, including novel scattering modeling and Doppler spectra characterization. As proved later, this channel model, which is based on both theoretical development and empirical data obtained in the surroundings of a real wind farm, is adaptable to the particular features of any case under study: wind turbine dimensions, working frequency, and relative location of the wind farm, transmitter and receivers.This work was supported in part by the European Union FP7 (grant agreement n 296164), by the Spanish Ministry of Economy and Competitiveness (project TEC2012-32370), and by the Basque Government (SAIOTEK program)

Characterization of non-intentional emissions from distributed energy resources up to 500 kHz: A case study in Spain

[EN] Narrow Band Power Line Communications (NB-PLC) systems are currently used for smart metering and power quality monitoring as a part of the Smart Grid (SG) concept. However, non-intentional emissions generated by the devices connected to the grid may sometimes disturb the communications and isolate metering equipment. Though some research works have been recently developed to characterize these emissions, most of them have been limited to frequencies below 150 kHz and they are mainly focused on in-house electronic appliances and lightning devices. As NB-PLC can also be allocated in higher frequencies up to 500 kHz, there is still a lack of analysis in this frequency range, especially for emissions from Distributed Energy Resources (DERs). The identification and characterization of the emissions is essential to develop solutions that avoid a negative impact on the proper performance of NB-PLC. In this work, the non-intentional emissions of different types of DERs composing a representative microgrid have been measured in the 35–500 kHz frequency range and analyzed both in time and frequency domains. Different working conditions and coupling and commutation procedures to mains are considered in the analysis. Results are then compared to the limits recommended by regulatory bodies for spurious emissions from communication systems in this frequency band, as no specific limits for DERs have been established. Field measurements show clear differences in the characteristics of non-intentional emissions for different devices, working conditions and coupling procedures and for frequencies below and above 150 kHz. Results of this study demonstrate that a further characterization of the potential emissions from the different types of DERs connected to the grid is required in order to guarantee current and future applications based on NB-PLC.This work has been financially supported in part by the Basque Government (Elkartek program)

A comprehensive review of the impact of transmission technologies on the electrical grid

The electrical infrastructure needs the integration of communication technologies, and in recent decades the progress has been significant. Therefore, this work presents the latest advances in this subject, as well as new functionalities.The work brings together the advances in automation, from the early stages to the present day. At the moment, the Smart Grid needs to use communication technologies to enable a response to demand, which wilt allow a different relationship between customer and company. The work presents the existing network architectures and communication protocols used in the Smart Grid. The document presents the challenges of electrical infrastructure, and shows the benefits and drawbacks of different communication technologies. In summary, the paper shows the parallel evolution of the communication technologies and the electrical grid, as a basic aspect for the development of new functionalities and services for all the agents involved in the power generation-transmission-distribution system.The authors thank the CYTED Thematic Network "Ciudades Inteligentes Totalmente Integrables, Eficientes y Sostenibles (CITIES)" no 518RT0558. This work has been financially supported in part by the Basque Government (Elkartek program)