Abstract
Today, the power system of the Baltic States (comprised of Lithuania, Latvia, and Estonia) is synchronized with the Integrated/Unified Power System (IPS/UPS) of Russia and Belarus. It is planned that by 2025 they desynchronize from the IPS/UPS system and to join the largest interconnection in the world, Continental Europe. The goal of this master thesis is to delve further into planned out-year operations in the European power grid with the synchronized connection of the Baltic States. To understand this topology, there needs to be a methodology for performing the power system analyses of the interconnected large power grid, particularly the case when the smaller grid is being connected to a large power system and when the models available are limited in terms of fidelity and completeness.
The focus of this research is threefold: 1) develop a procedure on how to find an AC solution from an approximated DC solution; 2) present a methodology for building the transmission system model from scratch using only publicly available data and 3) conduct dynamic studies to ensure reliable operation of the interconnected system. In this research, an open-source European grid model will be used, however, the available model was only built to study simple DC power flow solutions. The process of finding an AC solution from a DC one has been a difficult topic for the power system industry, and a new methodology on how to achieve this is proposed and will be discussed and demonstrated. The Baltic States transmission power grid equivalent will be added by using publicly available data for the transmission system topology, generation capacity, and load distribution. Finally, dynamic generation machine and control models are going to be introduced and assigned to the model, based upon the type of generation that exists at each location (or large-scale equivalent).
The built model of the integrated grid will allow a wide range of studies, from steady state to dynamic and it will help in the development of the new control and protection schemes to assist in increased system stability. To demonstrate the value of the developed model, a transient stability analysis will be performed on the interconnected model to analyze both the impact of the Baltic States on the dynamic stability of the interconnected grid, and the impact of events in the European grid on the Baltic States through the synchronous connection.