Performance evaluation of secondary control policies with respect to digital communications properties in inverter-based islanded microgrids

A key challenge for inverted-based microgrids working in islanded mode is to maintain their own frequency and voltage to a certain reference values while regulating the active and reactive power among distributed generators and loads. The implementation of frequency and voltage restoration control policies often requires the use of a digital communication network for real-time data exchange (tertiary control covers the coordi- nated operation of the microgrid and the host grid). Whenever a digital network is placed within the loop, the operation of the secondary control may be affected by the inherent properties of the communication technology. This paper analyses the effect that properties like transmission intervals and message dropouts have for four existing representative approaches to secondary control in a scalable islanded microgrid. The simulated results reveals pros and cons for each approach, and identifies threats that properly avoided or handled in advance can prevent failures that otherwise would occur. Selected experimental results on a low- scale laboratory microgrid corroborate the conclusions extracted from the simulation study.Peer ReviewedPostprint (author's final draft

Feasibility of the internet attachment-based compassion therapy in the general population: protocol for an open-label uncontrolled pilot trial

Background: Compassion-based interventions delivered over the internet are showing promising results for the promotion of psychological health and well-being. Several studies have highlighted their feasibility, acceptance, and preliminary efficacy. However, this is an incipient field of research, and to the best of our knowledge, there are no data available from Spanish-speaking countries. Objective: The aim of this study is to investigate the feasibility, acceptance, and preliminary efficacy of the Internet Attachment-Based Compassion Therapy (iABCT), a web-based version of the Attachment-Based Compassion Therapy, in Spanish speakers from the general population. Methods: This feasibility study features a single-arm, uncontrolled, within-group design with an embedded qualitative and quantitative process evaluation at baseline, immediately after the intervention and at the 3-month follow-up. A minimum of 35 participants from the general population will be allocated to iABCT. Feasibility measures will include attrition rate, patterns of use of the web-based system, and participants' acceptability, usability, and opinion. The primary outcome was measured using the Pemberton Happiness Index. Secondary outcomes were measured using the Compassion Scale, Self-Compassion Scale, Forms of Self-Criticizing/Attacking and Self-Reassuring Scale-Short form, Five Facets of Mindfulness Questionnaire, Relationships Questionnaire, General Health Questionnaire, Non-Attachment Scale, International Positive and Negative Affect Schedule Short Form, Purpose-In-Life Test, and difficulties regarding the practice of compassion (Compassion Practice Quality Questionnaire). Mixed models will be used to evaluate primary and secondary outcome measures. A qualitative content analysis of the participants' qualitative responses will also be performed. Results: Enrollment started in February 2020 and will be finished in April 2020. Data analysis will start in October 2020. Conclusions: To our knowledge, this study will, for the first time, show data on the feasibility, acceptability, and preliminary efficacy of web-based compassion (and self-compassion) training-that is, the adapted iABCT-in Spanish speakers from the general population. Further aspects of their implementation (ie, facilitators, barriers, and unwanted effects) and mechanisms of change will be investigated. This study will allow the revision and fine-tuning of the developed intervention, study design, and planning procedures, as well as the initiation of a future randomized controlled trial

CIBERER : Spanish national network for research on rare diseases: A highly productive collaborative initiative

Altres ajuts: Instituto de Salud Carlos III (ISCIII); Ministerio de Ciencia e Innovación.CIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a public national consortium created in 2006 under the umbrella of the Spanish National Institute of Health Carlos III (ISCIII). This innovative research structure comprises 11 different specific areas dedicated to the main public health priorities in the National Health System. CIBERER, the thematic area of CIBER focused on rare diseases (RDs) currently consists of 75 research groups belonging to universities, research centers, and hospitals of the entire country. CIBERER's mission is to be a center prioritizing and favoring collaboration and cooperation between biomedical and clinical research groups, with special emphasis on the aspects of genetic, molecular, biochemical, and cellular research of RDs. This research is the basis for providing new tools for the diagnosis and therapy of low-prevalence diseases, in line with the International Rare Diseases Research Consortium (IRDiRC) objectives, thus favoring translational research between the scientific environment of the laboratory and the clinical setting of health centers. In this article, we intend to review CIBERER's 15-year journey and summarize the main results obtained in terms of internationalization, scientific production, contributions toward the discovery of new therapies and novel genes associated to diseases, cooperation with patients' associations and many other topics related to RD research

Challenge B: Human sciences in transition scenarios

Coordinators: Josep Martí Pérez (IMF, CSIC), Idoia Murga Castro (IH, CSIC).This challenge is formulated in terms of “humanities in transition,” that is, their approach and articulation in the face of the changes they must undergo to achieve the social weight that, due to their intrinsic relevance, should correspond to them. Faced with these situations that would demand a reinforcement in research and dissemination in diverse aspects of the humanities, from multiple perspectives, paradoxically an adverse panorama is drawn for the development and dissemination of humanistic knowledge, which concerns different factors. Some are related to the consideration of the area of knowledge itself, its organization within the scientific system, the questioning of its own limits, and the interaction with another knowledge. Considering current transition scenarios does not mean having to abandon old objectives, but it adds to the work conducted new objects of study closely related to current reality, such as: the informational revolution; the relations with the ecosystem and the environmental crisis; globalization; the intensification of human mobility and migration flows; the growing economic and social inequality; the frictions derived from the articulation of collective identities; the decolonization of discourses; demographic dynamics; integration of technological advances; and viability and support for alternative models of society.Peer reviewe

Effects of clock deviations on the performance of microgrids based on virtual synchronous generators

An inverter-based microgrid is a small-scale power network governed by a distributed con-trol system. In this system, the nodes are the digital controllers of the power inverters,normally located at separate points within the microgrid. A relevant issue is that thesecontrollers operate at different frequencies due to inherent clock deviations in the localhardware oscillators. This paper evaluates the effects of these c lock deviations on the per-formance of microgrids equipped with inverters that emulate the operation of synchronousmachines. A systematic procedure is presented to derive steady-state expressions of theinverter active power and microgrid frequency as a function of clock drift rates. This pro-cedure is applied to swing and governor equations of the virtual synchronous generators,revealing the mechanism that allows clock drifts to be absorbed, making their presencenegligible. In addition, it allows recognising the controllers that should never be imple-mented in a distributed control system, since they cause an unsatisfactory behaviour thatcan even lead to a blackout in the microgrid. Therefore, the relevance of this study is theidenti¿cation of the control schemes that are most sensitive to clock drifts, which makesit easier to choose the most suitable control implementation for a particular application.Furthermore, technical guidelines are reported to help researchers on developing controlsolutions more robust to clock drifts. In this study, the theoretical results are validated byexperimental tests in a laboratory microgrid.This work was supported by the Ministry of Science, Innova-tion and Universities of Spain and by the European RegionalDevelopment Fund under project RTI2018-100732-B-C22.Peer ReviewedPostprint (published version

Performance evaluation of secondary control policies with respect to digital communications properties in inverter-based islanded microgrids

A key challenge for inverted-based microgrids working in islanded mode is to maintain their own frequency and voltage to a certain reference values while regulating the active and reactive power among distributed generators and loads. The implementation of frequency and voltage restoration control policies often requires the use of a digital communication network for real-time data exchange (tertiary control covers the coordi- nated operation of the microgrid and the host grid). Whenever a digital network is placed within the loop, the operation of the secondary control may be affected by the inherent properties of the communication technology. This paper analyses the effect that properties like transmission intervals and message dropouts have for four existing representative approaches to secondary control in a scalable islanded microgrid. The simulated results reveals pros and cons for each approach, and identifies threats that properly avoided or handled in advance can prevent failures that otherwise would occur. Selected experimental results on a low- scale laboratory microgrid corroborate the conclusions extracted from the simulation study.Peer Reviewe

Control strategies based on effective power factor for distributed generation power plants during unbalanced grid voltage

Unbalanced voltages in three-phase power systems is a common perturbation propagated along the grid. Distributed Generation plants have gained widespread attention due to their capability to improve power quality in a distributed manner, including voltage unbalance mitigation. A conventional control strategy to command power plants during balanced grid voltages, is the use of power factor to inject/absorb reactive power depending on grid conditions. Advanced control strategies during unbalanced grid voltages can be selected prioritizing positive or negative sequence active and reactive power. This selection determines the voltage support service and therefore can improve the voltage profile, i.e. phase-voltages can be properly supported and voltage imbalance simultaneously corrected. Based on the definition of effective power factor in IEEE 1459 Standard, the reactive power needed for any control strategy is obtained and the resulting effects are described.Peer Reviewe

Control strategies based on effective power factor for distributed generation power plants during unbalanced grid voltage

Unbalanced voltages in three-phase power systems is a common perturbation propagated along the grid. Distributed Generation plants have gained widespread attention due to their capability to improve power quality in a distributed manner, including voltage unbalance mitigation. A conventional control strategy to command power plants during balanced grid voltages, is the use of power factor to inject/absorb reactive power depending on grid conditions. Advanced control strategies during unbalanced grid voltages can be selected prioritizing positive or negative sequence active and reactive power. This selection determines the voltage support service and therefore can improve the voltage profile, i.e. phase-voltages can be properly supported and voltage imbalance simultaneously corrected. Based on the definition of effective power factor in IEEE 1459 Standard, the reactive power needed for any control strategy is obtained and the resulting effects are described.Peer Reviewe

Additional file 1 of Macular vessel density in the superficial plexus is not a proxy of cerebrovascular damage in non-demented individuals: data from the NORFACE cohort

Additional file 1. Multiple linear regression analyses of the association of clinical, demographic and biomarker variables with macular VD. Including hypertension, diabetes mellitus, dyslipidemia, heart disease, respiratory disease and smoking as adjusting factors. Significance was set up at p < 0.05. Abbreviations: A: amyloid; APOE: apolipoprotein E; CI: confidence interval; VD: vessel density