Due to deregulated energy market conditions and the planned extension of the UCTE power system towards Eastern Europe, as well as towards the Middle East and North Africa to close the so called “Mediterranean Ring”, the oscillation damping behaviour of the UCTE power system is gaining more and more in importance. Within the present paper, the oscillation damping behaviour of the enlarged UCTE p...

Anyone who have designed a capacitively tuned VFO/VCO with the wide tuning range (>1.5-2x) has noticed that the oscillation threshold changes substantially with the tuning frequency. The usual solution to the problem is a combination of: 1. the AGC circuit, most frequently via the amplifier bias that changes the amplifier conduction angle; 2. shunting the LC circuit with a damping resistor or b...

In this paper a new optimization algorithm, the biogeography based optimization (BBO) is employed to design a robust power oscillation damping (POD) controller using unified power flow controller (UPFC). The controller that is used to damp low frequency oscillation is designed over a wide range of operating points using two different objective functions. The obtained controllers are then verifi...

Damping in air gaps is studied at RF frequencies and modelled with a viscoelastic wave propagation model, since the traditional squeezed-film damping model is not valid in the MHz regime. The FEM study shows that above a certain frequency the wave propagation in the air gap can be modelled assuming closed damper borders. This closed-border problem is solved analytically from the linearized Navi...

In Japan, low-frequency oscillations have been observed on trunk transmission systems, and have been the subject for studies in fields of operation, control, and devices by many power system utilities. Power system stabilizers (PSS) are very effective controllers in enhancing the damping of low-frequency oscillations, since the controllers can increase damping torque for inter area modes by int...

Bubbly cavitating flow generated by the normal oscillation of a wall bounding a semi-infinite domain of fluid is computed using a continuum two-phase flow model. Bubble dynamics are computed, on the microscale, using the Rayleigh–Plesset equation. A Lagrangian finite volume scheme and implicit adaptive time marching are employed to accurately resolve bubbly shock waves and other steep gradients...

This paper presents a new approach for determining the effective control signals for damping of oscillations by performance comparison of Unified Power Flow Controller in coordination with Power Oscillation Damping Controller and Power System Stabilizer. For the analysis Modified Phllips-Heffron Model of Single Machine Infinite Bus system is established with Unified Power Flow Controller. Impac...

The damping behavior of bent fiber near-field scanning optical microscopy !NSOM" probes operating in tapping mode oscillation is investigated in air and water. We show that the significant drop in probe quality factor Q, which occurs at the air-water interface, is due to meniscus damping. As the probe is immersed in water viscous damping adds to the meniscus damping. Damping effects which lead ...

Deployment of distributed renewable energy resources is increasing rapidly, which is leading to growing concerns over the impact of distributed power electronics energy converters on grid stability. In general, power electronic coupled systems do not provide frequency or voltage support through feedback compensation. This is leading to changes in utility interconnection requirements for distrib...

p53 is a well-known tumor suppressor protein that regulates many pathways, such as ones involved in cell cycle and apoptosis. The p53 levels are known to oscillate without damping after DNA damage, which has been a focus of many recent studies. A negative feedback loop involving p53 and MDM2 has been reported to be responsible for this oscillatory behavior, but questions remain as how the dynam...