Power system harmonic current estimation method for wind power integration

Abstract

The present invention discloses a power system harmonic current estimation method for wind power integration. According to the method, firstly, the collected historical harmonic current data of each bus are subjected to wavelet decomposition and filtering, and then the high frequency components and the low frequency components of the data are obtained. Secondly, a harmonic current estimation measurement model and a state transition model are established. Finally, the harmonic current is estimated by adopting the variable-parameter kalman filtering method. According to the technical scheme of the invention, low frequency components, which embody the fluctuation rule of harmonic waves, are adopted as the preliminary estimation for the state of harmonic waves at the next moment. Meanwhile, a state transition matrix is estimated by utilizing the low frequency components. The daily fluctuation regularity of the injected harmonic current for an ordinary harmonic source load and a wind power harmonic source load is fully considered, and the estimation accuracy of the harmonic current is improved. High frequency components, which embody the randomness of the harmonic current, are adopted as the system noise and are used for estimating a system noise covariance matrix. Therefore, the complex noise parameter adjustment process of the kalman filtering method is avoided. The work load is reduced and the adaptability in different network structures is improved.

Description

technical field [0001] The invention relates to the technical field of grid harmonics, in particular to a method for estimating harmonic currents of power systems adapted to wind power access. Background technique [0002] With the massive application of nonlinear loads such as power electronic equipment, the harmonic pollution of the power grid has intensified, seriously affecting the safe and stable operation of the power grid. In order to provide users with high-quality electric energy, it is necessary to monitor and control harmonic pollution based on harmonic current estimation technology. [0003] In recent years, wind power has developed rapidly in the power system due to its clean, non-polluting, abundant resources, and renewable characteristics. Large-scale wind farms are integrated into the transmission grid through long-distance high-voltage direct current transmission, while small wind farms are integrated into the transmission and distribution grid in the form ...

AI Technical Summary

Problems solved by technology

The random and intermittent characteristics of wind power grid-connected injected harmonics cause the change of harmonic fluctuation characteristics and the aggravation of fluctuation amplitude in the entire regional power grid, making it difficult for existing harmonic current estimation methods to accurately track harmonic current fluctuations. bring great challenges

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