Browsing by Author "Eurasto, Vincent"

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Oikosulkuvirtojen ja -tehojen reaaliaikainen laskenta Suomen kantaverkossa
(2021-05-14) Eurasto, Vincent
Sähkötekniikan korkeakoulu | Bachelor's thesis
Tuning of the load-frequency controller for the Finnish power system
(2023-10-09) Eurasto, Vincent
Sähkötekniikan korkeakoulu | Master's thesis
Balancing the production and consumption of electricity is essential to uphold the power system and deliver electricity to all consumers. A power imbalance causes the system frequency to deviate from its nominal value, and extensive frequency deviations lead to the disconnection of production units due to the activation of equipment protection functions. In the Nordic countries, transmission system operators are responsible for balancing the power system in real-time. To achieve this, a number of reserve-providing units, such as power-generating units, consumption entities, and energy storages control their power exchange with the grid based on the frequency deviation or power imbalance. In recent years, the Nordic power system has been undergoing a transformation with an increasing share of renewable energy production and increased cross-border energy exchange. Maintaining the power balance and managing cross-border flows have become more challenging, leading the transmission system operators to develop a new balancing model. Currently, a centralized load-frequency controller is used to balance the whole Nordic power system by activating automatic frequency restoration reserves. In the new balancing model, the power system is divided into separate load-frequency control areas, each equipped with a load-frequency controller balancing the consumption and production in that area. Finland is one of those areas. In this thesis, the optimal parameters for the Finnish load-frequency controller were determined in a way that the balancing is efficiently and securely performed. In order to tune the controller, the essential dynamics of the power system and reserve-providing units were modeled. The modeled system was exposed to various operating conditions and imbalances in a simulation environment. In addition, an optimization method was developed to evaluate the performance of the controller over long time periods. Furthermore, the influence of the control dynamics of other areas on the choice of optimal parameters was studied. The magnitude of the power imbalances and the control dynamics of other areas were found to have an influence on the choice of the parameters. Nevertheless, the identified optimal parameters are robust to different operating conditions. Furthermore, the performed studies show that the addition of a low-pass filter to the control algorithm can improve the quality of the control signal.