A Method To Analyze Power Quality Disturbances Based Modified Atomic Decomposition

High power quality is the key to keep sustainable development of power system.The identification and classification of disturbance is the premise to depress the wicked influences produced by them. And the high-performance disturbance approach is the key to enhance the disturbance signal processing ability.On the basis of analyzing the theory of traditional signal analysis methods of power system and power quality concept, the application of atomic decomposition in power system disturbances is researched for the purpose of improving the effect of computation. An adaptive signal decomposition method is proposed to estimate parameters of power quality disturbances, which is called identification analysis of power quality disturbances based on harmony search and atom decomposition, and applied for the classification of complex power quality disturbances.First of all, in order to accelerate convergence speed, initial solution of matching pursuit is given by the approximate signal parameters which were obtained by discrete Fourier transform.Furthermore, based on characteristics of power quality disturbances, the Gabor dictionaries are divided into four subsets named as similar fundamental dictionary,pulse dictionary, harmonic dictionary and oscillation dictionary. The complexity of matching pursuit was then reduced by changing searching parameters.Finally, the matching pursuit algorithm was optimized by harmony search, which has advantages of fast speed and more accuracy in global search and cooperative search. The power quality disturbances parameter estimation is achieved by the index parameter of the Gabor dictionary. The simulation results show that the novel method could reduce the computation complexity, improve the search efficiency, accelerate the convergence speed, and enhance the accuracy of power quality disturbances parameter estimation, while also retains the advantage of signal reconstruction through matching pursuit.This paper applied the new novel to the classification of complex power quality disturbances. Firstly, add new energy thresholds to the novel, which is identification analysis of power quality disturbances based on harmony search and atom decomposition. Then, According to the relationship of signal energy between the disturbance components and the residual of wiped off fundamental component, thedisturbance types of power quality could be classified. Finally, an example is presented and is showed by experimental simulation to illustrate the availability of the algorithm.We simulated this algorithm in order to verify the effectiveness and feasibility of this algorithm.This work uses most power quality disturbances, which mainly include harmonics, voltage sags, voltage swells, voltage interrupts, flickers, oscillation transients, voltage sags with harmonic and voltage swells with harmonic. The complexity degree and convergence of the new novel were formulated.