This paper presents a comparison of measurement methods for current and voltage distortion in low voltage networks in the frequency range from 2 kHz to 150 kHz (supraharmonics). The comparison encompasses the methods informatively described in IEC and CISPR international standards, as well as other innovative techniques presented in the literature. The presented work is carried out within a novel framework that includes advanced and complex synthetic test signals, as well as real grid recordings, that allow an accurate comparison of the performance of the tested methods. Specifically designed indices are employed to characterize the accuracy of the tested methods in the frequency and amplitude assessment. In light of that, strengths and weaknesses of the methods are identified. The results of this paper contribute to the ongoing standardization work carried out by the IEC SC77A/WG9 with the purpose of defining a normative measurement method suitable for assessing grid disturbance levels in the range from 2 kHz to 150 kHz.

This study proposes a novel measurement method to assess the disturbances in the electrical grid for the CISPR Band A (9–150 kHz), as no normative grid measurement method for these frequencies exists yet. Compatibility levels (CL) in IEC 61000-2-2 in this frequency range are defined based on the CISPR 16-1-1 method using the quasi-peak (QP) detector. However, this method is not directly applicable for grid measurements as it was originally designed for laboratory conditions and for measuring radio disturbances and immunity. The method proposed in this article (Light-QP method) overcomes these limitations, along with lower complexity, computational burden, and memory requirements than CISPR 16-1-1. The Light-QP method uses a digital QP detector that processes root mean square (rms) values of spectral components, calculated by adapting the IEC 61000-4-7 standard to the CISPR Band A. The proposed Light-QP method is applied to real measurements from a low-voltage (LV) distribution grid and compared to the QP outputs from a digital implementation of the CISPR 16-1-1 method. The results are comparable and can be used for assessment against CL. The Light-QP method has been presented to IEC SC77A/WG9 for its potential inclusion as a normative measurement method in a new version of the IEC 61000-4-30 standard.

This work presents a novel measurement method to characterize long-term and short-term variations of the LV grid impedance from 20 kHz to 10 MHz with configurable time, frequency and amplitude resolutions. The characterization of the grid access impedance in this frequency range is vital for the design and development of NB-PLC and BB-PLC technologies. The measurement system is valid for in-home, indoor cable networks and for the harsh conditions of the LV distribution grid, where a large input dynamic range and strong protection mechanisms against high-amplitude impulsive noises are required. Its accuracy is evaluated by comparison to a precision impedance meter for a wide set of impedance values, obtaining a maximum deviation within ±8%. First trials of the grid impedance sub-cycle variations caused by commercial appliances and for frequencies assigned to BB-PLC are also presented in this paper. The results demonstrate that the grid impedance is highly time-varying within the mains cycle, both in amplitude and phase. These first outcomes point at the need to evaluate the accumulative effects of sub-cycle variations in the LV distribution grid, so that equalization algorithms in the next BB-PLC technologies could be developed to overcome the impact of these fast variations.

The access impedance of Low Voltage (LV) power networks is a major factor related to the performance of Narrow Band Power Line Communications (NB-PLC) 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 NB-PLC operates. The access impedance affects the transmission of the NB-PLC signal, and it determines the propagation of non-intentional emissions that may disturb other electrical devices, including malfunctioning or reduced lifetime of equipment. This work presents results of field measurements of 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 offers a better understanding of transmission of NB-PLC signals and EMC related phenomena.

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 article reviews the basis and the main aspects of the recent evolution of Broadband Power Line Communications (BB-PLC or, more commonly, BPL) technologies. The article starts describing the organizations and alliances involved in the development and evolution of BPL systems, as well as the standardization institutions working on PLC technologies. Then, a short description of the technical foundation of the recent proposed technologies and a comparison of the main specifications are presented; the regulatory activities related to the limits of emissions and immunity are also addressed. Finally, some representative applications of BPL and some selected use cases enabled by these technologies are summarized, together with the main challenges to be faced.