Power Quality in Microgrids Including Supraharmonics: Issues, Standards, and Mitigations

Abstract

A microgrid (MG) is a small-scale power system with a cluster of loads and distributed generators operating together through energy management software and devices that act as a single controllable entity with respect to the grid. MG has become a key research element in smart grid and distribution power systems. MG mainly contains different renewable energy sources (RESs) that use various technological advancements, such as power electronics-based technologies. However, it has an unstable output, thereby causing different types of power quality (PQ) events. As a result, standards and mitigation methods have been developed in recent years. To mitigate PQ issues due to MG integration, various methods and standards have been proposed over the last years. Although these individual methods are well documented, a comparative overview had not been introduced so far. Thus, this study aims to fill the gap by reviewing and comparing the prior-art PQ issues, solutions, and standards in MGs. We compare the main issues related to voltage sag, voltage swell, voltage and current harmonics, system unbalances, and fluctuations to ensure high-quality MG output power. The new technologies associated with MGs generate harmonics emission in the range of 2-150 kHz, thereby causing a new phenomenon, namely, supraharmonics (SH) emission, which is not sufficiently covered in the literature. Therefore, the characteristics, causes, consequences, and measurements of SH are highlighted and analyzed. The mitigation strategies, control, and devices of PQ issues are also discussed. Moreover, a comparison is conducted between the most popular devices used to mitigate the PQ issues in MG in terms of cost, rating, and different aspects of performance. This review study can strengthen the efforts toward the mitigation and standards development of PQ issues in MG applications, especially SH. Finally, some recommendations and suggestions to improve PQ of MG, including SH, are highlighted.

Offshore Wind Farm-Grid Integration: A Review on Infrastructure, Challenges, and Grid Solutions

“…primary emission. Secondly, flow of harmonic currents from the grid into the wind park termed as secondary emission [82]. The harmonic analysis of OWPP connected to the electric-grid can be conducted by an equivalent circuit depicted in Fig.…”

Maiden Voltage Control Analysis of Hybrid Power System With Dynamic Voltage Restorer

“…The use of converter in voltage controlling devices makes them costlier but they are important for continuous and smooth reactive power dispatch. Moreover, DVR is better than STATCOM [39] because the injection of the reactive power in the line is possible at different voltage magnitude and phase angle. The effectiveness of the VCDs in the proposed system can be clearly realized in Figure 6 (a).…”

Utilization of Renewable Energy for Power Sector in Yemen: Current Status and Potential Capabilities

“…Therefore, for fear of failure, people may not be willing to import and install renewable technologies. Besides, lack of transmission and distribution network physical infrastructure along with the required services and equipment of a national electrical company [20,[74][75][76]. Furthermore, insufficient management and equipment maintenance, combined with low technological reliability, lower customer confidence in certain RE technologies and thus hinder their deployment and adoption [77,78].…”