ABSTRACT
In a traditional large electricity grid without storage, there is a limit to the maximum photovoltaic energy that can be consumed as the demand and generation may not match, either in magnitude or in time. This paper aims to provide a new method to estimate the limit of the coverage of electricity demand by photovoltaics in large electricity grids. This new method eliminates the random and the periodic variability over time as it is based either on the load duration curve for demand and the output duration curve for PV generation. We will assume there is no energy storage or inter-network exchanges. Moreover, conditions for the best scenario for photovoltaics are provided in order to estimate the upper limit: photovoltaic overgeneration is not considered and a complete system flexibility is assumed. The knowledge of this limit will manage to provide not only a reference for the planning of the energy sector but also to analyze the viability of the integration of future photovoltaic projects in the electrical system. In order to illustrate the method, several large electricity grids have been analysed in order to determine the aforementioned limit. Values between 19.3% and 29.9% have been obtained.
ABSTRACT
La fibrilación auricular es muy frecuente en el paciente anciano. Aunque existe una amplia experiencia con los antagonistas de la vitamina K, el empleo de estos fármacos en el paciente anciano presenta numerosas limitaciones, con una mayor susceptibilidad a las hemorragias y un peor control de la anticoagulación que en la población general. Los anticoagulantes orales de acción directa han demostrado ser una mejor alternativa terapéutica para los pacientes ancianos, no solo por su mayor simplicidad de uso, sino por sus mayores eficacia y seguridad en comparación con los antagonistas de la vitamina K, con datos que en general concuerdan con los ensayos clínicos fundamentales. Sin embargo, en el paciente anciano hay una tendencia al uso de dosis inadecuadas, generalmente por infradosificación, sobre todo con algunos de ellos, lo que conlleva una menor protección contra los ictus, sin una clara ventaja antihemorrágica. El rivaroxabán se ha estudiado ampliamente en la población anciana y no solo en ensayos clínicos, sino también en multitud de estudios en la práctica clínica real, con datos muy consistentes. En estos estudios, en comparación con los antagonistas de la vitamina K, se ha demostrado que el rivaroxabán reduce el riesgo de ictus sin un incremento de las hemorragias mortales, con lo que tiene un beneficio clínico neto favorable en la población con fibrilación auricular no valvular con mayor riesgo tromboembólico
Atrial fibrillation is common in elderly patients. Although vitamin K antagonists have been widely used for many years, they have a number of limitations in elderly patients, who are particularly susceptible to bleeding and in whom anticoagulation control is poorer than in the general population. Direct oral anticoagulants have been shown to be a better therapeutic option for these patients, not only because they are simpler to use, but also because they are more effective and safer than vitamin K antagonists. Moreover, their performance in practice is generally consistent with that in pivotal clinical trials. Nevertheless, there is a tendency to administer inappropriate doses to elderly patients, generally underdosing, particularly in certain subgroups. This can result in less protection against stroke without any clear reduction in bleeding risk. Rivaroxaban has been widely studied in the elderly population, not only in clinical trials, but also in a range of studies in routine clinical practice - findings have been highly consistent. According to these studies, and compared to vitamin K antagonists, rivaroxaban reduces the risk of stroke without increasing the rate of fatal bleeding, with a net clinical benefit in patients with nonvalvular atrial fibrillation and a high thromboembolic risk
Subject(s)
Humans , Multiple Chronic Conditions/drug therapy , Anticoagulants/administration & dosage , Rivaroxaban/administration & dosage , Atrial Fibrillation/drug therapy , Stroke/prevention & control , Frailty/complications , Frailty/drug therapy , Polypharmacy , Aging/drug effects , 50293 , Vitamin K/antagonists & inhibitors , Antifibrinolytic Agents/administration & dosage , Warfarin/administration & dosageABSTRACT
Various challenges should be considered when measuring photovoltaic array power and energy in pulse width modulation (PWM) charge controllers. These controllers are frequently used not only in stand-alone photovoltaic (SAPV) systems, but may also be found in photovoltaic (PV) self-consumption systems with battery storage connected to the electricity grid. An acceptable solution may be reached using expensive data acquisition systems (DASs), although this could be generally disproportionate to the relatively low cost of SAPV systems. Therefore, the aim of this paper is to develop new and effective monitoring techniques which will provide the PV array direct current (DC), output power (PA,dc), and PV array DC output energy (EA), thus avoiding the use of sophisticated DASs and providing high accuracy for the calculated parameters. Only transducers and electronic circuits that provide the average and true rms values of the PWM signals are needed. The estimation of these parameters through the aforementioned techniques showed high accuracy for both series and shunt PWM battery charge controllers. Normalized root mean square error (NRMSE) was lower than 2.4%, normalized mean bias error (NMBE) was between -1.5% and 1.1%, and mean absolute percentage error (MAPE) was within 1.6%.
ABSTRACT
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