Is the Border Effect an Artefact of Geographic Aggregation?

The existence of a large border effect is considered as one of the main puzzles of international macroeconomics. We show that the border effect is, to a large extent, an artefact of geographic concentration. In order to do so we combine international flows with intranational flows data characterised by a high geographic grid. At this fine grid, intranational flows are highly localised and dropping sharply with distance. The use of a small geographical unit of reference to measure intra-national bilateral trade flows allows to estimating correctly the negative impact of distance on shipments. When we use sector disaggregated export flows of 50 Spanish provinces in years 2000 and 2005 split into interprovincial and inter-national flows, we find that the border effect is reduced substantially and even becomes statistically not different from zero in some estimations.border effect, distance, interregional trade, international trade, Spanish provinces

Análisis del impacto de las perturbaciones de canal sobre las tecnologías PLC de banda estrecha.

350 p

Is the border effect an artefact of geographic aggregation?

The existence of a large border effect is considered as one of the main puzzles of international macroeconomics. We show that the border effect is, to a large extent, an artefact of geographic concentration. In order to do so we combine international flows with intra-national flows data characterised by a high geographic grid. At this fine grid, intra-national flows are highly localised and dropping sharply with distance. The use of a small geographical unit of reference to measure intra-national bilateral trade flows allows to estimating correctly the negative impact of distance on shipments. When we use sector disaggregated export flows of 50 Spanish provinces in years 2000 and 2005 split into inter-provincial and inter-national flows, we find that the border effect is reduced substantially and even becomes statistically not different from zero in some estimations

Field Trials for the Empirical Characterization of the Low Voltage Grid Access Impedance From 35 kHz to 500 kHz

The access impedance of low-voltage (LV) power networks is a major factor related to the performance of the narrow-band power line communications (NB-PLCs) and, in a wider sense, to electromagnetic compatibility (EMC) performance. Up to date, there is still a lack of knowledge about the frequency-dependent access impedance for frequencies above 9 kHz and up to 500 kHz, which is the band where the NB-PLC operates. The access impedance affects the transmission of the NB-PLC signal, and it determines the propagation of the non-intentional emissions that may disturb other electrical devices, including malfunctioning or reduced lifetime of equipment. This paper presents the results of field measurements of the LV access impedance up to 500 kHz in different scenarios, with measurement locations close to end users and near transformers. The results provide useful information to analyze the characteristics of the LV access impedance, including variation with frequency, ranges of values for different frequency bands, and analysis of specific phenomena. Moreover, the results reveal a diverse frequency-dependent behavior of the access impedance in different scenarios, depending on the grid topology, the number of end users (that is, number and type of connected loads), and the type of transformation center. Overall, the results of this paper offer a better understanding of the transmission of NB-PLC signals and EMC-related phenomena.The authors would like to thank Iberdrola for the availability and the collaboration of authorized staff for carrying out the field trials

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

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)

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)

Analysis of the Channel Influence to Power Line Communications Based on ITU-T G.9904 (PRIME)

ITU-T G.9904 standard, also known as PoweRline Intelligent Metering Evolution (PRIME), is a Power Line Communications standard for advanced metering, grid control and asset monitoring defined by the International Telecommunication Union (ITU). In this paper, an analysis about how different characteristics of the communication channel and types of noise might affect the system performance is carried out. This study is based on simulations of the PRIME physical layer using different channel characteristics and transmission parameters. The conclusions obtained are very valuable for better understanding the behavior of the ITU-T G.9904 (PRIME) standard in the field, allowing future improvements in deployment strategies and equipment design

Análisis del impacto de las perturbaciones de canal sobre las tecnologías PLC de banda estrecha.

350 p