Public defence in Power Systems and High Voltage Engineering, M.Sc.(Tech.) Verner Püvi

The title of the thesis: Photovoltaic Hosting Capacity of Distribution Networks 

Doctoral student: Verner Püvi
Opponent: Prof. Mikko Kolehmainen, University of Eastern Finland
Custos: Prof. Matti Lehtonen, Aalto University School of Electrical Engineering, Department of Electrical Engineering and Automation

The rapid increase of photovoltaic (PV) installations has posed significant challenges to distribution networks worldwide. Some networks have already signaled that they have reached a critical point, unable to connect additional PV installations in some areas. This situation presents a pressing challenge as the adoption of PVs is far from complete and stable growth is anticipated in the coming decades. Distribution networks must fulfill their responsibilities in hosting distributed PV generation and supporting climate change mitigation efforts. 

My thesis addresses these challenges by exploring the hosting capacity, which measures the amount of installed PV power in a network without compromising normal operational requirements. The study investigates various limiting factors of hosting capacity, with a primary focus on steady-state power quality parameters and network structure. The thesis starts by presenting power quality measurement results, laying the groundwork for future power quality studies. Through Monte Carlo simulations, the impact of battery storage on the hosting capacity is analyzed, also examining how network structure influences the hosting capacity. Furthermore, a novel network topology optimization algorithm inspired by the behavior of slime mold organisms is presented. Additionally, the thesis provides insights into the practical aspects of hosting capacity estimation, by evaluating measurement uncertainty and finding its equivalent PV power. 

The results of the study reveal that approximately one-third of households can adopt PV systems if installations of the same magnitude continue in the future and voltage control measures are necessary to support continuous PV installations. Additionally, measurement uncertainty can account for up to one-fifth of generated PV power, showing the importance of maintaining a safety margin to meet the power quality standards.

Keywords: distribution networks, hosting capacity, network structure, optimization, photovoltaics, power quality, state estimation

Thesis available for public display 10 days prior to the defence at: https://aaltodoc.aalto.fi/doc_public/eonly/riiputus/

Contact information:

Doctoral theses in the School of Electrical Engineering: https://aaltodoc.aalto.fi/handle/123456789/53