Combined Unbalanced Distribution System State and Line Impedance Matrix Estimation

To address the challenges that the decarbonization of the energy sector is bringing about, advanced distribution network management and operation strategies are being developed. Many of these strategies require accurate network models to work effectively. However, distribution network data are known to contain errors, and attention has been given to techniques that allow to derive improved network information. This paper presents a novel method to derive line impedance values from smart meter measurement time series, with realistic assumptions in terms of meter accuracy, resolution and penetration. The method is based on unbalanced state estimation and is cast as a non-convex quadratically constrained optimization problem. Both line lengths and impedance matrix models can be estimated based on an exact nonlinear formulation of the steady-state three-phase network physics. The method is evaluated on the IEEE European Low Voltage feeder (906 buses) and shows promising results

Smart Energy Network Digital Twins: Findings from a UK-Based Demonstrator Project

Digital Twins promise to deliver a step-change in distribution system operations and planning, but there are few real-world examples that explore the challenges of combining imperfect model and measurement data, and then use these as the basis for subsequent analysis. In this work we propose a Digital Twin framework for electrical distribution systems and implement that framework on the Smart Energy Network Demonstrator microgrid in the UK. The data and software implementation are made available open-source, and consist of a network model, power meter measurements, and unbalanced power flow-based algorithms. Measurement and network uncertainties are shown to have a substantial impact on the quality of Digital Twin outputs. The potential benefits of a dynamic export limit and voltage control are estimated using the Digital Twin, using simulated measurements to address data quality challenges, with results showing curtailment for an exemplar day could be reduced by 56%. Power meter data and a network model are shown to be necessary for developing algorithms that enable decision-making that is robust to real-world uncertainties, with possibilities and challenges of Digital Twin development clearly demonstrated

Making Distribution State Estimation Practical: Challenges and Opportunities

In increasingly digitalized and metered distribution networks, state estimation is generally recognized as a key enabler of advanced network management functionalities. However, despite decades of research, the real-life adoption of state estimation in distribution systems remains sporadic. This systematization of knowledge paper discusses the cause for this while comparing industrial and academic experiences and reviewing well- and less-established research directions. We argue that to make distribution system state estimation more practical and applicable in the field, new perspectives are needed. In particular, research should move away from conventional approaches and embrace generalized problem specifications and more comprehensive workflows. These, in turn, require algorithm advancements and more general mathematical formulations. We discuss lines of work to enable the delivery of tangible research.Comment: 10 page

Can the Multidimensional Prognostic Index (MPI) be a predictive instrument for mortality in older adult liver transplant candidates?

PurposeThe most recent guidelines recommend that selection of liver transplant recipient patients be guided by a multidimensional approach that includes frailty assessment. Different scales have been developed to identify frail patients and determine their prognosis, but the data on older adult candidates are still inconclusive. The aim of this study was to compare the accuracy of the Liver Frailty Index (LFI) and the Multidimensional Prognostic Index (MPI) as predictors of mortality in a cohort of older people patients being evaluated for liver transplantation.MethodsThis retrospective study was conducted on 68 patients > 70 years being followed at the University Hospital of Padua in 2018. Clinical information on each patient, Model For End-Stage Liver Disease (MELD), Body Mass Index (BMI), Activities of Daily Living (ADL), Mini Nutritional Assessment (MNA), LFI, MPI, and date-of-death, were recorded. The observational period was 3 years.ResultsWe studied 68 individuals (25 women), with a mean age 72.21 & PLUSMN; 1.64 years. Twenty-five (36.2%) patients died during the observational period. ROC curve analysis showed both MPI and LFI to be good predictors of mortality (AUC 0.7, p = 0.007, and AUC 0.689, p = 0.015, respectively). MELD (HR 1.99, p = 0.001), BMI (HR 2.34, p = 0.001), and poor ADL (HR 3.34, p = 0.04) were risk factors for mortality in these patients, while male sex (HR 0.1, p = 0.01) and high MNA scores (HR 0.57, p = 0.01) were protective factors.ConclusionOur study confirmed the prognostic value of MPI in older adult patients awaiting liver transplantation. In this cohort, good nutritional status and male sex were protective factors, while high MELD and BMI scores and poor functional status were risk factors.Key summary pointsAimThe aim of this study was to compare the accuracy of the Liver Frailty Index (LFI) and the Multidimensional Prognostic Index (MPI) as predictors of mortality in a cohort of older adult patients being evaluated for liver transplantationFindingsOn the 68 patients studied, ROC curve analysis showed that MPI was similar or slightly better than LFI as predictor of mortality (AUC 0.7, p=0.007, and AUC 0.689, p=0.015, respectively).MessageIn older people patients listed for liver transplantation, MPI is as good a prognostic tool as LFI for predicting mortality

Leggere l’occupazione incrementale del territorio

A partire dagli anni novanta del secolo scorso, diversi studiosi hanno messo in luce la progressiva occupazione ed impermeabilizzazione del suolo che dal secondo dopoguerra agli albori della recente crisi economica ha interessato il Nord-Est d’Italia. Altri studiosi hanno avanzato l’ipotesi che vi sia una relazione diretta tra le intense trasformazioni urbanistiche avvenute negli ultimi decenni e le disfunzioni idrogeologiche che da tempo interessano ampie aree del Nord-Est. Il presente articolo restituisce gli esiti dell’analisi del processo di impermeabilizzazione del suolo nell’Alto Bacino del Fiume Sile, a nord-ovest di Treviso, un’area in cui negli ultimi decenni l’urbanizzazione si è manifestata con forza di pari passo con il consolidamento della nota città diffusa. L’alto bacino del Sile è un ambito idrogeologico particolarmente sensibile e spesso in sofferenza idraulica sia per i ricorrenti allagamenti sia per la mancanza d’acqua che interessa i coltivi. Su questo sfondo, la ricerca rilegge le trasformazioni incrementali del territorio a varie scale. L’indagine diacronica prende in esame il periodo che va dal secondo dopoguerra ad oggi e privilegia il ridisegno come strumento di restituzione evidenziando in tal modo che lo studio del processo di impermeabilizzazione della città diffusa debba necessariamente considerare gli effetti sul piano idraulico della reiterazione di trasformazioni spaziali alla piccola scala.info:eu-repo/semantics/publishe