In this paper the application of a hierarchical fuzzy system (HFS) based on MPSS and SVC in multi-machine environment is studied. Also the effect of communication lines active power variance signal between two ∆PTie-line regions, as one of the inputs of hierarchical fuzzy multi-input PSS and SVC (HFMPSS & SVC), on the increase of low frequency oscillation damping is examined. In the MPSS, to ha...

Vortex-induced vibration (VIV) of a long riser in sheared current is often considered as an energy balance problem: Excitation forces in the power-in region add an equal amount of energy to the system as is dissipated by damping forces outside this region and structural damping. A riser may have different excitation and damping regions depending on the actual oscillation frequency, cross-sectio...

We study the possibility of occurrence vibrational resonance in a softening Duffing oscillator underdamped and overdamped cases both theoretically as well numerically. The is driven by two periodic forces. Numerically we find that case oscillatory solutions are obtained limited range parameters considered (damping coefficient amplitude high frequency force) for fixed low force depending on init...

This study presents a study of the application of a Unified Power Flow Controller (UPFC) to control power transmission, generator terminals voltage and better damping of Low Frequency Oscillation (LFO) in Single-Machine Infinite-Bus (SMIB) power system. The UPFC integrates properties of both shunt and series compensations and can effectively alter power system parameters in a way that increases...

We introduce a new method to measure frequency separations and mode lifetimes of stochastically excited and damped oscillations, so-called solar-like oscillations. Our method shows that velocity data of the red giant star ξ Hya (Frandsen et al. 2002) support a large frequency separation between modes of roughly 7 µHz. We also conclude that the data are consistent with a mode lifetime of 2 days,...

Power system oscillation is a serious threat to the stability of multimachine power systems. The coordinated control of power system stabilizers (PSS) and thyristor-controlled series compensation (TCSC) damping controllers is a commonly used technique to provide the required damping over different modes of growing oscillations. However, their coordinated design is a complex multimodal optimizat...

" An apparatus for the measurement of liquid complex shear viscosity in the frequency range 80-2500 Hz, with the use of a torsion pendulum operating in forced oscillation, is described. The drive and detection system consists of a magnet inside the pendulum, two excitation and two measuring coils. The determination of the complex shear viscosity is based on the measurement of the resonance freq...

Power system oscillation damping remains as one of the major concerns for secure and reliable operation of large power systems, and is of great current interest to both industry and academia. The principal reason for this is that the inception of poorly-damped low-frequency inter-area oscillations (LFIOs) when power systems are operating under stringent conditions may lead to systemwide breakup...