Search results for "Landing"

973 Knee control and jump-landing technique in young basketball and floorball players

2016

Background Poor knee alignment is associated with increased loading of the joints, ligaments and tendons, and may increase the risk of injury. The study purpose was to compare differences in knee kinematics between basketball and floorball players during a vertical drop jump (VDJ) task. We wanted to investigate whether basketball players, whose sport includes frequent jump-landings, exhibited better knee control compared with floorball players, whose sport involves less jumping. Methods Players (aged 12–21 years) were recruited from six basketball and floorball clubs of the Tampere City district, Finland. Complete data was obtained from 173 basketball and 141 floorball players. Peak knee va…

Comparative Analysis of Different Types of Micro-grid Architectures and Controls

2018

An innovative and smart micro-grid model is an essentialfor the integration of distributed energy resources into the electrical power distribution network. There are various types of micro-grid architectures that have been designed and implemented in the last few years. These micro-grid architectures have their key advantages and limitations. This paper has been prepared with the objective to identify and address, key challenges and solutions for integration of micro-grid into the distribution network. It reviewsdifferent micro-grid architectures and control strategies which can help to address various challenges i.e. voltage imbalance, power quality, demand side management, smooth islandin…

Enhanced islanding detection in smart interface protection systems of distributed generation

2021

The widespread presence of distributed generators (DGs) and storage systems (DSSs) in electricity grids has increased the risk of islanding occurrence. This phenomenon must be suitably managed by Distribution System Operators (DSO), in order to avoid adverse situations, in terms of grid-protection problems, equipment damage, safety hazards, power quality problems and so on. Currently anti-islanding protection functions are handled by interface protection systems (IPSs), which are built in accordance with relevant standards for DGs and DSSs connection to power systems. However, some problems may occur in case of operation within the so-called non detection zone (NDZ). This paper presents an …

«Widrige Winde»: Der Abbruch der schonischen Expedition aus der Sicht des preußischen Gesandten, des Freiherrn Friedrich Ernst von Cnyphausen

2017

There are two interpretations of Peter the Great’s motives for refusing to land on the Swedish island of Schonen in historiography: that the tsar feared unforeseen military risks and that he did not trust his allies, Denmark and Great Britain. In this article, the author attempts to analyse in a more detailed way the reasons and consequences for the mistrust in the Northern Alliance by looking at communications by Baron Friedrich Ernst von Cnyphausen, the Prussian ambassador in Copenhagen. It is shown that the Russophobic hysteria which grasped the Danish royal court in September 1716 looks completely irrational when we consider parallel attitudes in the Prussian court. Cnyphausen does not …

Real-Time Implementation of Signal Processing Techniques for Disturbances Detection

2019

The real-time analysis of power quality (PQ) disturbances and islanding detection for distributed generation (DG) system using signal processing algorithms are still at a premature stage. Quick and reliable detection of islanding and PQ disturbances needs renewed focus. This paper is concentrated on the implementation of advanced signal processing techniques in field-programmable gate array (FPGA) to identify PQ and islanding events in real time. The proposed scheme is based on orthogonal empirical mode decomposition (OEMD) implemented in FPGA. This technique does not suffer from the loss of signal characteristics with successive decomposition levels. The performance of said technique is de…

SCELTA E APPLICAZIONE DI NUOVI STANDARD DI MANOVRA NELLE FASI DI DECOLLO ED ATTERRAGGIO DELL’ELICOTTERO - MODELLO E SPERIMENTAZIONE -

Una zona o un ambiente ha tipicamente un livello sonoro che lo caratterizza e ci si aspetta che le variazioni di quell’ambiente in equilibrio dovute ad un evento acustico insolito alterino le sensazioni delle persone in quel contesto. Non ci si può riferire al buon senso per valutare se disturbiamo o danneggiamo il prossimo, è necessario individuare le fonti di rumore e valutare l’impatto ambientale tramite indagini di tipo qualitativo e fasi sperimentali di misura. Lo studio condotto ha correlato il dato qualitativo a quello quantitativo sia in ambito predittivo che tramite rilievi sul campo. Gli scopi e gli obiettivi sono incentrati a: ricercare una simulazione coerente di propagazione de…

Smart interface devices for distributed generation in smart grids: The case of islanding

2017

With the increasing presence of distributed generators (DGs), the implementation of a smart sensors and actuators network in distribution grids has become crucial for different monitoring, management and protection functionalities. For DGs monitoring and control, sensors and actuators are usually embedded in so-called interface devices (IDs) or interface protection systems (IPSs). Existing IDs lack in communication interfaces both to the electrical energy Distribution System Operators (DSOs) and to the DGs inverter. In this framework, the authors have developed a new ID solution and a proper communication architecture, which allow implementing new smart functionalities based on the interact…

Fault Tolerant Ancillary Function of Power Converters in Distributed Generation Power System within a Microgrid Structure

2013

Distributed generation (DG) is deeply changing the existing distribution networks which become very sophisticated and complex incorporating both active and passive equipment. The simplification of their management can be obtained assuming a structure with small networks, namely, microgrids, reproducing, in a smaller scale, the structure of large networks including production, transmission, and distribution of the electrical energy. Power converters in distributed generation systems carry on some different ancillary functions as, for example, grid synchronization, islanding detection, fault ride through, and so on. In view of an optimal utilization of the generated electrical power, fault to…

Landing gear suspension control through adaptive backstepping techniques with H∞ performance

2011

Author's version of a chapter published in the book: Proceedings of the 18th IFAC World Congress 2011. Also available from the publisher at: http://dx.doi.org/10.3182/20110828-6-IT-1002.00589

Hybrid passive and communications-based methods for islanding detection in medium and low voltage smart grids

2013

Islanding condition takes place when a distributed generator (DG) continues to power a part of the grid even if power from electric utility is no longer present. Adverse effects of islanding are power quality deterioration, grid-protection interference, equipment damage, and personnel safety hazards. For these reasons, DG systems must detect an islanding condition and immediately disconnect from the grid (anti-islanding protection). This paper proposes an hybrid solution, for both low voltage (LV) and medium voltage (MV) applications, which makes use of passive and communication-based methods for islanding detection. Among the existing communication technologies, the study is focused on pow…