Verfahren zur Bewertung des dynamischen Verhaltens von Spannungsregelungen zur Flickerreduzierung
Bertram, Reinhold; Schnettler, Armin (Thesis advisor); Monti, Antonello (Thesis advisor)
Dissertation / PhD Thesis
Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2020
Perceptible changes in brightness that occur due to rapid voltage fluctuations are called flicker and can lead to health consequences for those affected. As a common countermeasure, compensation devices such as STATCOMs are used. Distributed generation systems are available in the power grid as a result of the large-scale implementation of the energy transition. As "virtual STATCOMs", they could be another solution for reducing flicker in distribution grids. Generation units coupled with a power-electronic interface already have the technical prerequisites to provide reactive power to the utility grid in short time and could therefore compensate for flicker without hardware upgrading. A procedure must be developed to evaluate the feasibility of this solution. This thesis presents an evaluation method that can be used to compare the performance of different technology portfolios and control systems with respect to their potential to reduce flicker - especially when considering distributed reactive power control systems such as "virtual STATCOMs". To this end the flicker reduction potential is defined and its calculation method presented, consisting of the steps for calculating the steady-state, the dynamic and the simulative potential. The main innovations of this approach are the adaptation of the hosting capacity method for flicker in combination with the application of non-linear optimization, with the use of an RMS flicker meter and with the time-domain simulation of reactive power controls. The evaluation method determines the flicker level that can be reduced below the threshold value defined in standards by the option of a "virtual STATCOM". The results of the exemplary investigation show that the level of the steady-state potential depends on the network topology, feed-in and load. The available reactive power is the main limiting factor. The time-dependent behavior of the reactive power control systems restricts the dynamic potential. Finally, the evaluation by means of the simulative potential shows how the potential for the control systems that can be implemented is dependent on the gradient of the characteristic curve and the controller speed.