Textbook in PDF format This book explains frequency quality in a comprehensive and systematic way. It does so by combining theoretical and practical knowledge on the topic. It includes dynamic simulations and real-world examples. For example, the book discusses the frequency performance of large-scale real-world power systems such as the Irish, UK, and Australian power systems. The book also presents a comprehensive analysis of the impact of different electricity market models, different control parameters, microgrids, topology, and converter-based demand on frequency quality. Then, the book provides an in-depth description of industry practice when it comes to frequency reserves dimensioning approaches and monitoring and reporting of frequency quality. The authors also clarify many terms related to frequency control and commonly used by the power system community