This book focuses on interval-based approaches for power flow and optimal power flow analysis in power systems under uncertainties from renewable generation and load demand. It addresses both theoretical foundations and practical applications, supported by detailed figures and tables. In particular, this book systematically examines key challenges in uncertain power flow and optimal power flow, emphasizing issues of convergence, accuracy, efficiency, conservatism, and data correlation. A major feature is the application of interval theory to tackle high-dimensional and severe uncertainties, offering practical insights for the secure operation of modern power systems with high renewable penetration. This book is especially suited for readers interested in interval optimization and practical solutions to power system uncertainty challenges. It benefits researchers, engineers, and graduate students in power system analysis, planning, optimization, scheduling, and uncertainty modeling.

Cong Zhang (Senior Member, IEEE) received his Ph.D. in Electrical Engineering from South China University of Technology, Guangzhou, China, in 2018. Currently, he is working as an associate professor with the College of Electrical and Information Engineering, Hunan University, Changsha, China. His research interests include planning, scheduling, and operational control of modern power systems, uncertainty analysis, and security margin assessment and optimization. His research is supported by China National Natural Science Foundation and Smart Grid-National Science and Technology Major Project. He has published one monograph, over 70 journal and conference papers, more than 20 granted invention patents, and won a State Scientific and Technological Progress Award from the Ministry of Education of China. He is serving as a Guest Editor for SCI journals, including Protection and Control of Modern Power Systems and IEEE Access.

Qian Liu received the Ph.D. degree in electrical engineering from the College of Electrical and Information Engineering, Hunan University, Changsha, China, in 2026. He has contributed to high-impact peer-reviewed journals. He is currently a Researcher with the Energy Development Research Institute, Energy and Power Planning Laboratory, China Southern Power Grid Co., Ltd., Guangzhou, China. His research interests include power system operation and optimization, interval power flow analysis, and reactive power optimization incorporating uncertainties.

Dapeng Wang received the Ph.D. degree in electrical engineering from Hunan University, Changsha, China, in 2026. He is currently working as a Lecturer at the College of Electrical and Information Engineering, Changsha University of Science and Technology, Changsha, China. His research interests cover security analysis and optimization of renewable energy power systems.