Morten Lind

Coordinated Charging of Electric Vehicles for Congestion Prevention in the Distribution Grid

Distributed energy resources (DERs), like electric vehicles (EVs), can offer valuable services to power systems, such as enabling renewable energy to the electricity producer and providing ancillary services to the system operator. However, these new DERs may challenge the distribution grid due to insufficient capacity in peak hours. This paper aims to coordinate the valuable services and operation constraints of three actors: the EV owner, the Fleet operator (FO) and the Distribution system operator (DSO), considering the individual EV owners driving requirement, the charging cost of EV and thermal limits of cables and transformers in the proposed market framework. Firstly, a theoretical market framework is described. Within this framework, FOs who represent their customers (EV owners) interests will centrally guarantee the EV owners driving requirements and procure the energy for their vehicles with lower cost. The congestion problem will be solved by a coordination between DSO and FOs through a distribution grid capacity market scheme. Then, a mathematical formulation of the market scheme is presented. Further, some case studies are shown to illustrate the effectiveness of the proposed solutions.

Estimating vegetative productivity gradients around watering points in the rangelands of Northern Senegal based on NOAA AVHRR data

Abstract This paper tests the hypothesis that high dry season grazing pressures around watering points in rangelands in northern Senegal has a negative effect on vegetative productivity. Time series of NOAA AVHRR satellite images for three rainy seasons are used to estimate integrated NDVI (iNDVI) at a resolution of I km2, and assess the dependence of iNDVI on distance to the nearest dry season water source. The observed ‘iNDVI gradients’ around watering points differ greatly between watering points and through time, leading to a rejection of the hypothesis. Possible explanations are discussed, and it is argued that iNDVI gradients are not well-suited as indicators of land degradation.

Means and ends of control

Means-end analysis plays a significant role in cognitive engineering and has been successfully applied in several work domains, usually in the form of Rasmussens abstraction hierarchy. However, work domains with embedded controls create problems and modifications of the abstraction hierarchy has been proposed to circumvent the problems. But embedded controls is a deep problem for means-end analysis in general and not only for instances like the abstraction hierarchy. It is pointed out that means-end analysis is currently not used in control engineering but should be used to clarify modelling assumptions. Means-end analysis also lacks a proper definition of the control concept. It is proposed that control is defined as a binary relation that assign functional roles to subsystems. This control concept leads to distinct but entangled process and control hierarchies. It is argued that the problems of embedded control can be resolved by an analysis of the relations between the two types of hierarchy. Illustrative modelling examples are included

Reasoning about Control Situations in Power Systems

Introduction of distributed generation, deregulation and distribution of control has brought new challenges for electric power system operation, control and automation. Traditional power system models used in reasoning tasks such as intelligent control are highly dependent on the task purpose. Thus, a model for intelligent control must represent system features, so that information from measurements can be related to possible system states and to control actions. These general modeling requirements are well understood, but it is, in general, difficult to translate them into a model because of the lack of explicit principles for model construction. Available modeling concepts for intelligent control do not assist the model builder in the selection of model content i.e. in deciding what is relevant to represent for a particular reasoning task and thereby faced with a difficult interpretation problem. In this paper, we present our work on using explicit means-ends model based reasoning about complex control situations which results in maintaining consistent perspectives and selecting appropriate control action for goal driven agents. Index Terms—Power Systems, Intelligent Control, Multiagent Systems, Means-Ends reasoning, Situation Awareness, Control Situations

Use of the prognostic biomarker suPAR in the emergency department improves risk stratification but has no effect on mortality: a cluster-randomized clinical trial (TRIAGE III)

BackgroundRisk stratification of patients in the emergency department can be strengthened using prognostic biomarkers, but the impact on patient prognosis is unknown. The aim of the TRIAGE III trial was to investigate whether the introduction of the prognostic and nonspecific biomarker: soluble urokinase plasminogen activator receptor (suPAR) for risk stratification in the emergency department reduces mortality in acutely admitted patients.MethodsThe TRIAGE III trial was a cluster-randomized interventional trial conducted at emergency departments in the Capitol Region of Denmark. Eligible hospitals were required to have an emergency department with an intake of acute medical and surgical patients and no previous access to suPAR measurement. Three emergency departments were randomized; one withdrew shortly after the trial began. The inclusion period was from January through June of 2016 consisting of twelve cluster-periods of 3-weeks alternating between intervention and control and a subsequent follow-up of ten months. Patients were allocated to the intervention if they arrived in interventional periods, where suPAR measurement was routinely analysed at arrival. In the control periods suPAR measurement was not performed. The main outcome was all-cause mortality 10xa0months after arrival of the last patient in the inclusion period. Secondary outcomes included 30-day mortality.ResultsThe trial enrolled a consecutive cohort of 16,801 acutely admitted patients; all were included in the analyses. The intervention group consisted of 6 cluster periods with 8900 patients and the control group consisted of 6 cluster periods with 7901 patients. After a median follow-up of 362xa0days, death occurred in 1241 patients (13.9%) in the intervention group and in 1126 patients (14.3%) in the control group.The weighted Cox model found a hazard ratio of 0.97 (95% confidence interval, 0.89 to 1.07; pxa0=u20090.57). Analysis of all subgroups and of 30-day all-cause mortality showed similar results.ConclusionsThe TRIAGE III trial found no effect of introducing the nonspecific and prognostic biomarker suPAR in emergency departments on short- or long-term all-cause mortality among acutely admitted patients. Further research is required to evaluate how prognostic biomarkers can be implemented in routine clinical practice.Trial registrationclinicaltrials.gov, NCT02643459. Registered 31 December 2015.