A method of estimating damping parameters for multidegree-of-freedom vibration systems is outlined, involving a balance of dissipated and supplied energies over a cycle of periodic vibration. The power is formulated as the inner product between velocity and force terms, and integrated over a cycle. Conservative terms (mass and stiffness) drop out of the formulation. The displacement response an...

Wind is becoming an increasingly significant source of energy in modern power generation. Amongst existing technologies, Variable Speed Wind Turbines (VSWT) equipped with Double Fed Induction Generators (DFIG) is widely deployed. Consequently, power systems are now experiencing newer power flow patterns and operating conditions. This paper investigates the impact of a DFIG based Wind Farm (WF) ...

The structural operating conditions may significantly differ from those applied during laboratory tests where the structure is well known, well installed and properly excited. For structures under their natural loading conditions, or excited by random forces, excitations cannot be measured and are usually non stationary. Hence, an improvement operational modal analysis is a useful complement to...

A method is proposed in order to calculate the damping effects of viscous fluids in liquid storage tanks subjected to earthquakes. The potential equation of an ideal fluid can satisfy only the boundary conditions normal to the surface of the liquid. To satisfy also the tangential interaction conditions between liquid and tank wall and tank bottom, the potential flow is superimposed by a one-dim...

This paper presents a combined approach based on Prony analysis and radial basis function neural network for monitoring small signal stability and parameter tuning of power system stabilizer. Prony analysis method is used to estimate the modal components of low frequency oscillations associated with synchronous generators. In this method, the measured (simulated) time-domain signal is decompose...

Static Var compensator (SVC) is one of flexible AC transmission system (FACTS) elements mainly used for reactive power and voltage control in power systems. This paper deals with multi-modal electromechanical oscillations damping in the presence of severe disturbances. These oscillations include local modes, interarea modes and inter-plant modes. To enhance the damping of the oscillations, a co...

This paper describes a comparison, both analytically and experimentally, between two widely used loss factor estimation techniques frequently used in statistical energy analysis. Analytical models of simple spring/mass/damper systems were created to compare frequency-averaged loss factor values from the single subsystem power injection method and the impulse response decay method. The parameter...

Abstract. In this study, the seismic soil–structure interaction (SSI) of wind turbine support structures is investigated based on complex mode superposition approach. For accurate and efficient estimation loadings structures, an augmented response spectrum method (RSM) developed, where maximum shear force bending moment non-classically damped system are analytically derived. An empirical formul...

in practice, foundations are settled on the soft layers of soil, so the ground must be designed as well as the structure. wave propagation and hysteresis damping of soil layers may alter the seismic response of flexible-base design in comparison to controversial fixed-base. lots of uncertainties about this issue, necessitate most of seismic design standards including iranian standard no. 2800 t...