Showing 3 results for Resonance
H. Abbasi, A. Gholami, A. Abbasi, ,
Volume 7, Issue 1 (3-2011)
Abstract
This paper consist of two sections: control and stabilizing approach for chaotic behaviour of converter is introduced in first section of this paper for the removal of harmonic caused by the chaotic behaviour in current converter. For this work, a Time- Delayed Feedback Controller (TDFC) control method for stability chaotic behaviour of buck converter for switching courses in current control mode is presented. This behaviour is demonstrated by presenting a piecewise linear discrete map for this converter and then combining the feedback equation to obtain the overall equation of the converter. A simple time-delay feedback control method is applied to stabilize the Unstable Periodic Orbits (UPOs). In second section is studied the effect of a parallel metal oxide surge arrester on the ferroresonance oscillations of the transformer. It is expected that the arresters generally cause ferroresonance drop out. Simulation has been done on a three phase power transformer with one open phase. Effect of varying input voltage has been studied. The simulation results reveal that connecting the arrester to the transformer poles, exhibits a great mitigating effect on ferroresonant over voltages. Phase plane along with bifurcation diagrams are also presented. Significant effect on the onset of chaos, the range of parameter values that may lead to chaos and magnitude of ferroresonant voltages has been obtained, shown and tabulated.
H. Radmanesh, M. Rostami,
Volume 7, Issue 4 (12-2011)
Abstract
this work studies the effect of neutral earth resistance on the controlling ferroresonance oscillation in the power transformer including MOV surge arrester. A simple case of ferroresonance circuit in a three phase transformer is used to show this phenomenon and the three-phase transformer core structures including nonlinear core losses are discussed. The effect of MOV surge arrester and neutral earth resistance on the onset of chaotic ferroresonance and controlling chaotic transient in a power transformer including nonlinear core losses has been studied. It is expected that these resistances generally cause into ferroresonance control. Simulation has been done on a power transformer rated 50 MVA, 635.1 kV with one open phase. The magnetization characteristic of the transformer is modelled by a single-value two-term polynomial with q=7, 11. The core losses are modelled by third order in terms of voltage. The simulation results reveal that connecting the MOV arrester and neutral resistance to the transformer, exhibits a great impact on ferroresonance over voltages.
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A. Hesami Naghshbandy, K. Naderi, U. D. Annakkage,
Volume 18, Issue 3 (9-2022)
Abstract
The most challenging circumstance of forced oscillations (FOs) is when the power system is forced to oscillate at its natural frequencies. This paper uses a novel PMU data-driven mechanism to pinpoint the source of such phenomena under resonance. Following the detection of FOs, the instantaneous changes in the output power and angular velocity of the rotors are calculated. Accordingly, an energy-driven multilateral interaction pattern is obtained for all synchronous generators. Next, an appropriate positive weighted undirected graph is constructed through these functional patterns based on the spectral graph theory. These quantitative indicators are then analyzed through the eigenvalue spectrum of the normalized Laplacian matrix of the system graph reduced to the internal generator buses. Finally, the smallest value in eigenvectors corresponding to the two largest eigenvalues reveals the location of the source. The proposed methodology’s validation and verification studies have been performed on the WECC 3-machine 9-bus and New England 10-machine 39-bus benchmark power systems modeled in the Real-Time Digital Simulator (RTDS) and then analyzed in the MATLAB environment. The proposed methodology revealed to be fast and accurate in locating the source of FOs under challenging resonance situations with promising results while addressing the generator side origins.
