Harmonic analysis of hybrid renewable microgrids comprising optimal design of passive filters and uncertainties

• Published in: Electric power systems research 2018-10, Vol.163, p.491-501
• Main Authors: Elkholy, Mahmoud M., El-Hameed, M.A., El-Fergany, A.A.
• Format: Article
• Language: English
• Subjects: Alternative energy sources; Critical frequencies; Design optimization; Distributed generation; Electric power grids; Electricity distribution; Filters; Fourier analysis; Genetic algorithms; Harmonic analysis; Harmonic distortion; Hybrid microgrids; Induction motors; Multi-objective optimization; Multiple objective analysis; Power factor; Power sources; Sizing of passive harmonic filters; Technique for order of preference by similarity to ideal solution (TOPSIS); Torque; Turbogenerators; Uncertainty; Wind turbines; Windpowered generators
• ISSN: 0378-7796; 1873-2046
• DOI: 10.1016/j.epsr.2018.07.023

•Applications of passive filters in grid-connected and isolated hybrid microgrid are addressed.•The used passive filters have dual purposes: (1) improve the power factor, and (2) suppress the harmonics.•Cost of passive filters plus voltage total harmonic distortion represent the bi-objectives.•Optimal sizing of filters are realised by using grasshopper optimizer and compared to genetic algorithm results.•Many test cases are demonstrated comprising the uncertainties of renewable energy sources. In this paper, the applications of passive filters in grid-connected and isolated hybrid renewable microgrid are addressed. The single-tuned filters are engaged to reduce the total harmonic distortion (THD) at the point of common connection with keeping total demand distortions below the maximum allowable limits. The total cost of proposed passive filters along with THD define the adapted bi-objectives to be minimized simultaneously provided that set of operating inequality constraints are satisfied. A multi-objective grasshopper optimization algorithm (MOGOA) is applied in this regard. The best answers are picked up carefully among the Pareto solutions by technique for order of preference by similarity to ideal solution (TOPSIS) procedures. Harmonic analysis is performed to examine the critical frequencies in many instants before and after installing passive filters. The effects of harmonics on the motor and wind generator torques are analysed and discussed. In addition, the system power factor is improved. Various scenarios regarding the operations of the grid under study are investigated comprising uncertainties of renewable power sources. The reductions in torque ripples of induction motor and wind turbine generator are indicated. It can be emphasized that the cropped results of filter’s cost along with THD generated by MOGOA are very competitive and convincing when they are compared to the results of the well-structure multi-objective genetic algorithm.