Dynamic Grid Support by Wind Farms: Potential of Rotating Kinetic Energy (Dynamische netondersteuning door windparken: potentieel van roterende kinetische energie)

Since the beginning of this century, Renewable Energy Sources for Electricity (RES-E) and mostly wind power have gained a huge momentum and are continuously triggering new stability challenges. The rising capacity of RES-E in the generation mix already poses challenges to current operation of power systems and subsequently sets the direction for new approaches to control them. This dissertation deals with operational problems, primarily arising duringfavorable weather conditions for RES-E and low demand. During such conditions, the framework for system operation of today sets limits to the instantaneous output of RES-E because system operators rely on conventional power plants to provide the necessary grid support. The pursuit for a generation mix with quasi only RES-E requires the provision of support by RES-E. Subsequently, the focus of this dissertation is on enabling RES-E, with a significant share of Variable Speed Wind Turbines (VSWTs) in the provision of grid support, preserving the same level of power system stability. This dissertation firstly analyzes the impact of proposed support modes of VSWTs on grid stability. Dynamic voltage and frequency support modes are evaluated in grid topologies hosting a rising share of wind power. Such studies show that the effectiveness of supporting modes is highly dependent on the specific grid topology. Additionally, the resulting interaction with other gridelements, such as induction motors and load shedding schemes, provides new insights to fine-tune the support by wind turbines in the future.Secondly, the potential of rotating kinetic energy in VSWTs is evaluated to smooth power variations from large wind farms, or to assist in the task of system frequency regulation. To this end, an optimization framework is constructed to calculate the trade-off between maximizing energy yield and smoothing power or frequency variations. The results show a significant potential for smoothing that benefits both from the coordination among individual turbines and from forecasting the prevailing wind.1. Introduction 2. Wind power development and control Part I Grid impact of dynamic support by wind farms 3. Dynamic voltage support by wind farms equipped with DDSGs 4. Frequency response support by wind farms equipped with DDSGs Part II Optimal control of rotating kinetic energy in wind farms 5. Distribution and control of a kinetic energy reserve among individual turbines 6. Trading energy yield for power smoothing 7. Trading energy yield for frequency regulation 8. Conclusions and further researchSince the beginning of this century, Renewable Energy Sources for Electricity (RES-E) and mostly wind power have gained a huge momentum and are continuously triggering new stability challenges. The rising capacity of RES-E in the generation mix already poses challenges to current operation of power systems and subsequently sets the direction for new approaches to control them. This dissertation deals with operational problems, primarily arising during favorable weather conditions for RES-E and low demand. During such conditions, the framework for system operation of today sets limits to the instantaneous output of RES-E because system operators rely on conventional power plants to provide the necessary grid support. The pursuit for a generation mix with quasi only RES-E requires the provision of support by RES-E. Subsequently, the focus of this dissertation is on enabling RES-E, with a significant share of Variable Speed Wind Turbines (VSWTs) in the provision of grid support, preserving the same level of power system stability. This dissertation firstly analyzes the impact of proposed support modes of VSWTs on grid stability. Dynamic voltage and frequency support modes are evaluated in grid topologies hosting a rising share of wind power. Such studies show that the effectiveness of supporting modes is highly dependent on the specific grid topology. Additionally, the resulting interaction with other grid elements, such as induction motors and load shedding schemes, provides new insights to fine-tune the support by wind turbines in the future. Secondly, the potential of rotating kinetic energy in VSWTs is evaluated to smooth power variations from large wind farms, or to assist in the task of system frequency regulation. To this end, an optimization framework is constructed to calculate the trade-off between maximizing energy yield and smoothing power or frequency variations. The results show a significant potential for smoothing that benefits both from the coordination among individual turbines and from forecasting the prevailing wind.nrpages: 222status: publishe