نتایج جستجو برای: electromechanical oscillations

تعداد نتایج: 54851  

2008
Tobias Gehrke Heinrich M. Overhoff

Pulse-echo ultrasound signal formation can be simulated by numerical emulation of the process chain: emit signal – electromechanical emit transformation – wave propagation and scattering – electromechanical receive transformation – receive signal. The simulation software Field II is indented for simulation of linear ultrasound systems. We present an extension to Field II that enables the inclus...

2012
Luigi Vanfretti Sebastian Bengtsson Vemund H. Aarstrand Jan O. Gjerde

For power networks such as the Nordic Grid, that have operation constraints limits imposed by the existence of low-damped electromechanical oscillations, the estimation of electromechanical mode properties is of crucial importance for providing power system control room operators with adequate indicators of the stress of their network. This article addresses the practical application of differe...

In this paper, the modified linearized Phillips-Heffron model is utilized to theoretically analyze asingle-machine infinite-bus (SMIB) installed with SSSC. Then, the results of this analysis are used forassessing the potential of an SSSC supplementary controller to improve the dynamic stability of apower system. This is carried out by measuring the electromechanical controllability through sing...

The safe operation of power system depends on its stability and security supply in all times. The dynamic instability (small signal instability) is one of phenomena that results in power system instability and has been discussed as a challenge in power system control and operation from a long time ago. Commonly the dynamic instability appears as undamped low frequency electromechanical oscillat...

Fariba Heidarpour Ghazanfar shahgholian,

The sustainability of hydraulic turbines was one of the most important issues considered by electrical energy provider experts. Increased electromechanical oscillation damping is one of the key issues in the turbines sustainability. Electromechanical oscillations, if not quickly damp, can threaten the stability of hydraulic turbines and causes the separation of different parts of the netw...

Journal: :Nano letters 2007
Anthony Ayari Pascal Vincent Sorin Perisanu May Choueib Vincent Gouttenoire Mikhael Bechelany David Cornu Stephen T Purcell

We report the observation of self-oscillations in a bottom-up nanoelectromechanical system (NEMS) during field emission driven by a constant applied voltage. An electromechanical model is explored that explains the phenomenon and that can be directly used to develop integrated devices. In this first study, we have already achieved approximately 50% dc/ac (direct to alternating current) conversi...

2007
Ali T. Al-Awami

The use of the supplementary controllers of a unified power flow controller (UPFC) to damp low frequency oscillations in a weakly connected system is investigated. The potential of the UPFC supplementary controllers to enhance the dynamic stability is evaluated by measuring the electromechanical controllability through singular value decomposition (SVD) analysis. Individual designs of the UPFC ...

Journal: :IOP Conference Series: Earth and Environmental Science 2020

2012
Kodukula Sowmya Indranil Saaki

–Low frequency electromechanical oscillations are inevitable characteristics of power systems and they greatly affect the transmission line transfer capability and power system stability. Traditionally, power system stabilizers (PSS) are being used to damp these oscillations. Unified Power Flow Controller (UPFC) is a well-known FACTS device that can control power flow in transmission lines. It ...

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