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About this book

This book reports on a comprehensive study addressing the dynamic responses of hydropower plants under diverse conditions and disturbances, and analyzes their stability and oscillations. Multiple models based on eight existing hydropower plants in Sweden and China were developed and used for simulations and theoretical analysis with various degrees of complexity and for different purposes, and compared with on-site measurements for validations. The book offers important insights into the understanding of the hydraulic, mechanical and electrical coupling mechanisms, up to market conditions and incentives. It recommends control strategies for a more stable and efficient operation of hydropower plants.

Table of Contents

Frontmatter

1. Introduction

Abstract
Hydropower has played an important role in the safe, stable and efficient operation of electric power systems for a long time. Hydropower not only generates electricity as the largest global renewable source, but also shoulders a large portion of the regulation and balancing duty in many power systems all over the world. In this chapter, power system stability and features of hydropower generating systems are briefly introduced; the related previous research and the hydropower research at Uppsala University is reviewed; then the scope and outline of this thesis are presented.
Weijia Yang

2. Methods and Theory

Abstract
In this chapter, the methods and theory of this thesis are briefly displayed. In Sect. 2.1, principles of three main methods used in this thesis are presented. In Sect. 2.2, practical engineering cases adopted in this thesis are introduced.
Weijia Yang

3. Various Hydropower Plant Models

Abstract
In this thesis, various HPP models for different study purposes are developed. For a clearer demonstration and classification of models, they are distinguished from two aspects: (1) the implementation and (2) the generator modelling approach, as shown in Fig. 3.1. In this chapter, numerical Models in TOPSYS and MATLAB, models for theoretical derivation and numerical models in MATLAB for HPPs with Kaplan Turbines are built and presented.
Weijia Yang

4. Stable Operation Regarding Frequency Stability

Abstract
The stable operation of HPPs regarding frequency stability of power systems is analysed in this chapter. In Sect. 4.1, case studies on different operating conditions of HPPs are conducted, and the simulation performance of Model 1 based on TOPSYS is presented. In Sect. 4.2, response time of PFC in HPPs is investigated under grid-connected operation. In Sect. 4.3, frequency stability of HPPs in isolated operation is studied.
Weijia Yang

5. Stable Operation Regarding Rotor Angle Stability

Abstract
The stable operation of HPPs regarding rotor angle stability of power systems is studied in this chapter. In Sect. 5.1, a fundamental study on hydraulic-mechanical-electrical coupling mechanism for small signal stability of HPPs is conducted by Eigen-analysis. Considerable influence from hydraulic-mechanical factors is shown, and it is further quantified in Sect. 5.2: An equivalent hydraulic turbine damping coefficient and the corresponding methodology are proposed to quantify the contribution on damping of rotor angle oscillations from hydraulic turbines based on refined simulations. In Sect. 5.3, the quick hydraulic—mechanical response is discussed to support the results in this chapter. The engineering case of all sections is HPP 5.
Weijia Yang

6. Efficient Operation and Balancing Renewable Power Systems

Abstract
In this chapter, the efficient operation of HPPs during balancing actions for renewable power systems is studied, focusing on PFC that acts on a time scale from seconds to minutes. In Sect. 6.1, the problem description, cause and initial analysis of wear and tear of turbines are presented. Based on the analysis results, a controller filter is proposed in Sect. 6.2 as a solution for reducing the wear of turbines and maintaining the regulation performance, reflected by the frequency quality of power systems. Then in Sect. 6.3, the study is further extended by proposing a framework that combines technical plant operation with economic indicators, to obtain relative values of regulation burden and performance of PFC.
Weijia Yang

7. Conclusions

Abstract
In this chapter, the summary of results and the general conclusions are presented, then the future works are discussed.
Weijia Yang

Backmatter

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