Microgrids are local energy production and distribution networks that can operate independently when disconnected from the main power grid thanks to the integration of power generation systems, energy storage units and intelligent control systems. However, despite their advantages, the optimal energy management of real microgrids remains a subject that requires further investigation. Specifically, an effective management of microgrids requires managing a large number of electrical variables related to the power generated by the microgrid’s power supplies, the power consumed by the loads and the aspects of power quality. This study analyzes how we can monitor different variables, such as the active power, reactive power, power factor, total harmonic distortion and frequency in the loads of a microgrid, using high-precision power meters. Our empirical study, conducted using a functional microgrid comprising a hybrid wind–solar power system and several household appliances, demonstrates the feasibility of using low-cost and high-performance power meters with IoT functionality to collect valuable power quality and energy consumption data that can be used to control the microgrid operation.

Background: Unlike Transposable Elements (TEs) and gene/genome duplication, the role of the so-called nuclear plastid DNA sequences (NUPTs) in shaping the evolution of genome architecture and function remains poorly studied. We investigate here the functional and evolutionary fate of NUPTs in the orphan crop Moringa oleifera (moringa), featured by the highest fraction of plastid DNA found so far in any plant genome, focusing on (i) any potential biases in their distribution in relation to specific nuclear genomic features, (ii) their contribution to the emergence of new genes and gene regions, and (iii) their impact on the expression of target nuclear genes. Results: In agreement with their potential mutagenic effect, NUPTs are underrepresented among structural genes, although their overall transcription levels and broadness were only lower when involved exonic regions; the occurrence of plastid DNA generally did not result in a broader expression, except among those affected in introns by older NUPTs. In contrast, we found a strong enrichment of NUPTs among specific superfamilies of retrotransposons and several classes of RNA genes, including those participating in the protein biosynthetic machinery (i.e., rRNA and tRNA genes) and a specific class of regulatory RNAs. A significant fraction of NUPT RNA genes was found to be functionally expressed, thus potentially contributing to the nuclear pool. Conclusions: Our results complete our view of the molecular factors driving the evolution of nuclear genome architecture and function, and support plastid DNA in moringa as a major source of (i) genome complexity and (ii) the nuclear pool of RNA genes.

Beyond the massive amounts of DNA and genes transferred from the protoorganelle genome to the nucleus during the endosymbiotic event that gave rise to the plastids, stretches of plastid DNA of varying size are still being copied and relocated to the nuclear genome in a process that is ongoing and does not result in the concomitant shrinking of the plastid genome. As a result, plant nuclear genomes are featured by a small, but variable, fraction of their genomes of plastid origin, the so-called nuclear plastid DNA sequences (NUPTs). However, research on the topic was mostly focused on a limited number of species and of plastid DNA. Here, we leveraged a chromosome-scale version of the Moringa oleifera genome, featured by the largest fraction of plastid DNA in any plant nuclear genome, to examine the chromosomal distribution and arrangement of NUPTs, to explicitly model and test the correlation between their age and size distribution, as well as to characterize their sites of origin at the chloroplast genome and their sites of insertion at the nuclear one. We found a bimodal distribution of NUPT relative ages, which implies NUPTs in moringa were formed through two separate events. Furthermore, NUPTs from every event showed markedly distinctive features, suggesting they originated through distinct mechanisms. Our results reveal an unanticipated complexity of the mechanisms at the origin of NUPTs and of the evolutionary forces behind their fixation and highlight moringa species as an exceptional model to study the mechanisms of origin and evolutionary fate of NUPTs. Significance statement: Sequencing of plant genomes has revealed the presence of a variable, but significant, content of DNA arising from their organelles, i.e. , plastids and mitochondria. However, the mechanisms underlying their origin and fixation are not yet fully elucidated. Here, by thoroughly examining the spatial and temporal distribution of the large fraction of plastid DNA present in the nuclear genome of the orphan crop Moringa oleifera , we identified their episodic origin trough seemingly distinct mechanisms, highlighting the complexity of the molecular and evolutionary dynamics underlying their origin and fixation and revealing moringa as an outstanding model to assess the impact of plastid DNA in the evolution of the architecture and function of plant nuclear genomes.

A new methodology for visualizing power quality (PQ) events in three-phase circuits is presented. It employs an Euclidean vector space to represent 4D information embedded in a 3D point-cloud-like curve in time domain. We exploit the recently developed concept of Cyclic Histograms in single-phase systems by extending and modifying it to multi-phase power systems. Triplets of voltages (line-to-line or line-to-neutral) are used as coordinates of points that are assigned to specific regions in space (voxels). Over time, a counter for each voxel is incremented whenever the discrete trajectory transits the voxel. A color is then assigned to every voxel depending on the final count. The results showed that the color and shape of the spatial trajectories provide information regarding harmonic distortion, voltage unbalance, and transient phenomena. This method can also be applied to current waveforms. Some examples are provided using real-world waveforms to highlight the benefits of the proposed work.