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A novel decentralized method for harmonics detection and suppression is proposed. Compared with the traditional centralized style, harmonics optimal estimation task in micro-grid system is scattered to smart phasor measurement unit (PMU) nodes without a monitoring host. Similar to the structure, mechanism and characteristics of biological communities, a smart PMU can communicate with adjacent nodes...
This paper presents an optimization approach based differential search algorithm (DSA) for amplitude and phase estimation of time varying power signal in electrical power systems. Proposed method has been tested for two well-known literature problems that include fundamental, sub- and inter-harmonic estimation cases. The performance of the suggested DSA method has been compared with those of the Genetic...
Multi-pitch estimation concerns the problem of estimating the fundamental frequencies (pitches) and amplitudes/phases of multiple superimposed harmonic signals with application in music, speech, vibration analysis, and other fields. In this paper we formulate a complex-valued multi-pitch estimator via a semidefinite programming method for continuous sparse optimization over an infinite dictionary...
In this work, we consider the problem of multi-pitch estimation using sparse heuristics and convex modeling. In general, this is a difficult non-linear optimization problem, as the frequencies belonging to one pitch often overlap the frequencies belonging to other pitches, thereby causing ambiguity between pitches with similar frequency content. The problem is further complicated by the fact that...
This paper presents a new hybrid algorithm for harmonic estimation. The algorithm combines a simple fast population based search algorithm with Least Squares Method. It is based on the structural property of the harmonic estimation problem which implies that the signal model is linear in amplitude and nonlinear in phase. The hybrid algorithm uses the search algorithm for phase estimation and LS for...
This paper improves K-dominated sorting by M2M population decomposition [14] to enhance the population convergence and diversity, and propose a new evolutionary many objective optimization algorithm based on the improved Kdominated sorting. The proposed K-dominated sorting can maintain the population diversity by M2M population decomposition. What's more, we prove that the improved K-dominance can...
Multiple distributed harmonic sources, such as inverter-interfaced distributed generation (DG), in distribution systems have posed new challenges in identifying the cause of harmonic voltages or currents observed at a specific location. This paper proposes a new method to estimate harmonic contribution using nonlinear optimization techniques. First, definitions are provided and the problems are described...
The accurate detection and location of a fault is crucial for power systems applications such as protective relaying and phasor measurement. As fault signals have unique mathematical expressions, this paper proposes a computational intelligence based method to estimate the parameters of the fault signal towards the minimum difference between the input signal and the reconstructed one. The optimization...
LCL filter has the advantage of small size and strong inhibition of high frequency harmonic currents. The parameter design of LCL filter mostly considers switching frequency harmonics. The attenuation of single-time harmonic current is always treated as optimization target. Thus the designed parameters may too large. What's more, the THD requirement is not easy to verify. This paper proposes an optimization...
In the recent years, several hybrid algorithms have been proposed for the estimation of power system harmonics. These hybrid algorithms generally include an optimization algorithm. The presented study proposes to estimate integral harmonics using Differential Evolution optimization algorithm. To enhance the estimation capability of the proposed algorithm, the frequency deviation and interharmonic...
The three-phase voltage and current waveforms from a Power System (PS) are not considered pure sinusoids due to the presence of, among others, the harmonic distortion. This work presents an approach based on the Particle Swarm Optimization (PSO) method for the harmonic component estimation in a PS. PSO is a technique of search/optimization that models the social behavior observed in many species of...
We consider the problem of aligning high angular resolution diffusion images characterized by orientation distribution functions (ODFs). We cast this problem as an optimization problem where we seek the rotation that aligns the source and target ODFs. This rotation induces a linear transformation of the spherical harmonic coefficients of the ODFs, which can be parametrized by the rotation Euler angles...
The matter density is an important knowledge for today cosmology as many phenomena are linked to matter fluctuations. However, this density is not directly available, but estimated through lensing maps or galaxy surveys. In this article, we focus on galaxy surveys which are incomplete and noisy observations of the galaxy density. Incomplete, as part of the sky is unobserved or unreliable. Noisy as...
Growing interest in power quality has led the international working groups to define new measurement techniques to apply to power systems. Special attention has been paid to harmonic and inter-harmonic measurements. This paper presents a new method to optimize harmonic estimation in power systems. The method uses filter bank property of discrete wavelet packet transform to measure the harmonics; and...
This paper presents a dynamic bacterial swarming algorithm (DBSA) for harmonic estimation in dynamic environment. DBSA is designed from a dynamic searching framework that combines the underlying mechanisms of bacterial chemotaxis, quorum sensing and environment adaptation. The harmonic estimation process utilizes DBSA to estimate the phases of the harmonics, alongside a least square (LS) method to...
The treatment of channel state information (CSI) is critical in the design of MIMO systems. Accurate CSI at the transmitter is often not possible or may require high feedback rates. Herein, we consider the robust design of linear MIMO transceivers with perfect CSI either at the transmitter or at both sides of the link. The framework considers the design problem where the imperfect CSI consists of...
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