In an era defined by the rapid evolution of energy technologies and the necessity of sustainable power generation, effective voltage control is a critical component in optimizing the performance of the power distribution grid and the seamless integration of renewable energy sources. This thesis presents the development and evaluation of an adaptive voltage control policy for high voltage to medium voltage transformers aimed at mitigating voltage limit violations in modern power distribution networks.

The motivation for this research arises from the increasing integration of distributed energy resources and the growing complexity of power grids, which require dynamic and robust voltage management strategies. The proposed policy utilizes a voltage control curve, optimized using a genetic algorithm, which systematically identifies the best parameters for the curve to ensure voltage stability and minimize violations across diverse grid configurations.

The methodology involves quasi-dynamic simulations performed on 30 real-world distribution grids, which test the effectiveness of the voltage control curves in maintaining grid stability under varying load and generation conditions. This was done by setting a stricter ±3% voltage limit for the medium voltage grid. Results show an average reduction of 88.54% in voltage limit violations and a 17.19% decrease in the maximum difference between the maximum and minimum voltage levels in the medium voltage grid throughout a complete year (2023). This study highlights the importance of a grid-specific voltage control curve, as every distribution grid exhibited unique voltage regulation needs.

Furthermore, the policy was evaluated under projected grid scenarios, demonstrating sustained effectiveness across two future timeframes: one set five years and the other ten years into the future. In the first scenario (2028), an 80.06% reduction in voltage limit violations was achieved, while the second scenario (2033) still showed a reduction of 62.25%.

Through the genetic algorithm optimization, the voltage control policy adapts to fluctuating grid dynamics, contributing to improved power quality and the successful integration of distributed energy resources. While effective in medium voltage grids, further research is needed to explore the policy’s applicability to low voltage networks and in environments with limited data availability.

The simplicity and universality of the proposed adaptive voltage control strategy make it a practical solution for real-world deployment, as it can be implemented on existing hardware. In contrast, the proposed strategy alone will not be enough to completely eliminate all the voltage stability problems in distribution grids and additional measures are necessary. However, by minimizing voltage violations and improving grid resilience, this work offers a robust framework for voltage management in modern, evolving power distribution networks, particularly in the context of the global energy transition towards sustainable energy sources. ... Read more

As electric vehicles are quickly taking over the automotive industry, electric airplanes are also starting their upswing. With air travel and transport in general being a large polluter of CO2 gases, the transition to electric flight becomes more prominent every year. This transition is starting small with non-commercial airplanes. Several companies are starting with development of eVTOLs, electric Vertical Take-Off and Landing vehicles. The idea behind them is that they can easily move into and out of the city through the air, speeding up transport and travel in urban areas while keeping CO2 emissions at the vehicle level at zero.
This thesis, together with two other theses, will elaborate on the design of such an eVTOL. Its design is created by looking at the layout of the propellers, the wings and the fuselage and the internal layout is composed by working out the electric drivetrain from the energy storage to the electric motors and by drafting up the control systems. In specific, this thesis dives into the external design and the internal electric energy storage. It does this by settling on a design and calculating certain specifications, like wing area and propeller and fuselage size. From there the necessary powers and energies are calculated. With these powers and energies, a battery pack is designed together with a battery management system and a charging system. The other two theses will design the propulsion system and the control system of the eVTOL.
The result of the thesis is a theoretical design that states the possibilities of Lithium-Sulfur cells inside an eVTOL. An efficient tandem wing design with fixed wings and fixed rotors makes sure there is a healthy balance between the maximum power and total energy needed to take off vertically and fly 125 kilometers. With the Lithium-Sulfur cells a battery pack is made with its accompanying battery management system that monitors and manages the cells' characteristics. Next to the battery pack, theory on charging and a simplified charging simulation has been done to show that charging in 15 minutes should be possible by the time the eVTOL enters into service. ... Read more