Review of frequency regulation requirements for wind power plants in international grid codes

The system inertia is gradually decreasing and frequency security issues are becoming more prominent with the increasing penetration of wind power. To ensure the safety and stability of power system, many countries have updated their grid codes to reinforce the frequency regulation requirements (FRRs) for wind power plants (WPPs). However, most review articles on grid codes cover all grid-integration metrics, while the review of FRRs is inadequate and incomplete; moreover, it shall be updated to accommodate the state-of-the-art grid codes. To cope with it, this study presents a comprehensive review of FRRs for WPPs in modern grid codes, covering 12 representative countries or organizations such as those with the highest development level, the fastest development speed, and the largest installations in wind power. The FRRs in their grid codes for wind power integration are compared and analyzed from three aspects: frequency operating range, primary frequency response and inertia response. Based on the comparative analysis, combined with relevant policy documents, some future trends related to FRRs are concluded. Furthermore, electricity generation sources in each country are analyzed to enrich the understanding of the reasons behind the differences in FRRs. The review helps the transmission system operator to compare and analyze international grid codes and optimize their own grid codes. Moreover, it enables wind turbine manufacturers to master the latest grid codes and grasp the future trends, and helps research focus on practical needs and solve the pain points of wind power development.