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  • Book cover of Power System Wide-area Stability Analysis and Control
    Jing Ma

     · 2018

    An essential guide to the stability and control of power systems integrating large-scale renewable energy sources The rapid development of smart grids and the integration of large scale renewable energy have added daunting new layers of complexity to the long-standing problem of power system stability control. This book offers a systematic stochastic analysis of these nonlinear problems and provides comprehensive countermeasures to improve power system performance and control with large-scale, hybrid power systems. Power system stability analysis and control is by no means a new topic. But the integration of large scale renewable energy sources has added many new challenges which must be addressed, especially in the areas of time variance, time delay, and uncertainties. Robust, adaptive control strategies and countermeasures are the key to avoiding inadequate, excessive, or lost loads within hybrid power systems. Written by an internationally recognized innovator in the field this book describes the latest theory and methods for handling power system angle stability within power networks. Dr. Jing Ma analyzes and provides control strategies for large scale power systems and outlines state-of-the-art solutions to the entire range of challenges facing today’s power systems engineers. Features nonlinear, stochastic analysis of power system stability and control Offers proven countermeasures to optimizing power system performance Focuses on nonlinear time-variance, long time-delays, high uncertainties and comprehensive countermeasures Emphasizes methods for analyzing and addressing time variance and delay when integrating large-scale renewable energy Includes rigorous algorithms and simulations for the design of analysis and control modeling Power System Wide-area Stability Analysis and Control is must-reading for researchers studying power system stability analysis and control, engineers working on power system dynamics and stability, and graduate students in electrical engineering interested in the burgeoning field of smart, wide-area power systems.

  • Book cover of Electromagnetic Transient Analysis and Novel Protective Relaying Techniques for Power Transformers

    An advanced level examination of the latest developments in power transformer protection This book addresses the technical challenges of transformer malfunction analysis as well as protection. One of the current research directions is the malfunction mechanism analysis due to nonlinearity of transformer core and comprehensive countermeasures on improving the performance of transformer differential protection. Here, the authors summarize their research outcomes and present a set of recent research advances in the electromagnetic transient analysis, the application on power transformer protections, and present a more systematic investigation and review in this field. This research area is still progressing, especially with the fast development of Smart Grid. This book is an important addition to the literature and will enhance significant advancement in research. It is a good reference book for researchers in power transformer protection research and a good text book for graduate and undergraduate students in electrical engineering. Chapter headings include: Transformer differential protection principle and existing problem analysis; Malfunction mechanism analysis due to nonlinearity of transformer core; Novel analysis tools on operating characteristics of Transformer differential protection; Novel magnetizing inrush identification schemes; Comprehensive countermeasures on improving the performance of transformer differential protection An advanced level examination of the latest developments in power transformer protection Presents a new and systematic view of power transformer protection, enabling readers to design new models and consider fresher design approaches Offers a set of approaches to optimize the power system from a microeconomic point of view

  • Book cover of Hierarchical Protection for Smart Grids

    A systematic view of hierarchical protection for smart grids, with solutions to tradition protection problems and complicated operation modes of modern power systems • Systematically investigates traditional protection problems from the bird’s eye view of hierarchical protection • Focuses on multiple variable network structures and complicated operation modes • Offers comprehensive countermeasures on improving protection performance based on up-to-date research

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    No author available

     · 1945

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    Abstract: Background Bodily distress syndrome (BDS) is a new, empirical-based diagnosis of functional somatic symptoms. This study aimed to explore the prevalence of BDS and its association with psychosocial variables in a Chinese clinical population. Methods A multicentre cross-sectional study of 1269 patients was conducted in 9 different Chinese tertiary outpatient hospitals. The BDS was identified by trained interviewers face-to face, based on a brief version of the Schedules for Assessment in Neuropsychiatry (RIFD) and the BDS Checklist-25. Sociodemographic data and further information were characterised from psychometric questionnaires (The Patient Health Questionnaire-15, the Patient Health Questionnaire-9, the General Anxiety Disorder-7, the Whiteley scale-8) . Results Complete data were available for 697 patients. The prevalence of BDS was 26.8% (95% confidence interval (CI): 23.5-30.1). Among the participants, 5.8% (95% CI: 4.1-7.6) fulfilled the criteria for single-organ BDS, while 20.9% (95%CI: 17.9-24.0) had multi-organ BDS. Comparison of the PHQ-15, PHQ-9, GAD-7, and WI-8 scores revealed higher scores on all dimensions for patients with BDS. In a binary logistic regression analysis, BDS was significantly associated with increased health-related anxiety (WI-8) and depression (PHQ-9). The explained variance was Nagelkerke's R2 = 0.42. Conclusions In China, the BDS is a common clinical condition in tertiary outpatient hospital settings with high prevalence, and is associated with health anxiety and depressive symptoms. In this clinical population, the severe multi-organ subtype of BDS was the most frequent

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