Hybrid FFT-ADALINE algorithm with fast estimation of harmonics in power system

Hybrid fast Fourier transform Adaptive LINear Element (FFT-ADALINE) algorithm for fast and accurate estimation of harmonics is proposed in this study. The FFT method can perform fast conversion from time domain to frequency domain, but it cannot respond immediately to any change of the measured harmonics due to the utilisation of buffer. Meanwhile, ADALINE has better capability to respond immediately due to its learning ability, but its settling time is about two cycles of the measurement signal. In the proposed method, both of the aforementioned algorithms are combined for harmonic estimation where it is able to respond immediately to any change of the measured harmonics and the settling time is reduced to half cycle of the measurement signal. The theory of the proposed algorithm is the application of FFT with weights updating rule to reduce the error of ADALINE instantaneously. The robustness of the proposed method is simulated via MATLAB Simulink. The validity of the simulation work is further proven by the experimental work, which has been done with Chroma programmable AC source model 6590 and non-linear load operations. The proposed algorithm operates in good and accurate performance with the settling time is within half cycle

Enhanced harmonic state estimation in unbalanced three-phase electrical grids based on the Kalman filter and physical scale-down implementation

A time-domain methodology is proposed based on Kalman filter, to determine the harmonic state estimation in three-phase electrical grids. Time-domain methodologies based on the Kalman filter need an initial solution to begin estimating the harmonic state in electrical grids. Previous methods have found this solution using simulated electrical grids; thus, the measurements taken from the simulations are synchronised only with the simulated grid model. In practical power networks, measurements taken from the grid need to be synchronised with the theoretical grid model. Synchronization between the model and measurements using the Kalman filter is proposed. This paper also proposes an alternative method to obtain the periodic steady-state solution in power grids. The method adequately processes the information given by a limited number of measurements to find the required solution. An experimental case study for a three-phase unbalanced condition with a nonlinear load and a limited number of measurements is used to validate the proposed methodology, i.e. practical data has been used instead of synthetic data. Hence, the results are validated by direct comparison of the state estimation response against the actual data recorded from the experimental laboratory implementation. The results show that using the proposed methodology, the time-domain harmonic state estimation can be efficiently applied to the analysis of practical power grids

Técnicas para el Análisis Espectral de Armónicos en Sistemas Eléctricos de Potencia

En este artículo se realizó una investigación bibliográfica sobre las técnicas más utilizadas en sistemas eléctricos de distribución e industriales para el análisis espectral de armónicos. Se elaboró una tabla comparativa de las técnicas encontradas de más de 40 artículos científicos de la IEEE de acuerdo a sus ventajas, desventajas y campo de aplicación en sistemas eléctricos de potencia.El resultado de ésta investigación muestra la viabilidad de aplicación de cada una de estas técnicas para el análisis de armónicos según el régimen de operación (Estacionario, No-Estacionario, Transitorio) de la señal analizada en cargas no-lineales