Voltage unbalance factor detection based Kaiser- maximum sidelobe decay convolution window and amplitude method.

• A negative voltage unbalance factor calculation method based on the amplitude method. • A K-MSD convolution window and three-spectral line interpolated FFT algorithm that can calculate voltage fundamental wave amplitude, improving the calculation accuracy. • A voltage unbalance factor detection system is developed and implemented in a platform. The wide application of distributed energy and nonlinear load causes the voltage unbalance of power grid. This paper establishes an accurate method based on the Kaiser- maximum sidelobe decay (K-MSD) convolution window and three-spectral line interpolated FFT algorithm and the amplitude method to detect the negative sequence voltage unbalance factor. The voltage fundamental wave amplitude is calculated by improved FFT algorithm, which improves the calculation accuracy. Then, the negative sequence voltage unbalance factor is calculated by the amplitude method. It avoids complex phasor calculations. Based on the proposed method the voltage unbalance factor detection system is developed and implemented in a platform. The simulation experiment results show that the proposed algorithm in this paper can effectively realize the accurate detection of unbalance factor under the interference of fundamental wave, harmonics and noise. Compared with the method recommended by the IEC61000-4-27, it is easy to implement and can achieve the same level of precision. [ABSTRACT FROM AUTHOR]