Modeling and steering of multi-use operation with uninterruptible power supply systems utilizing the example of lead-acid batteries

Badeda, Julia; Sauer, Dirk Uwe (Thesis advisor); Monti, Antonello (Thesis advisor)

Aachen : ISEA (2019, 2020)
Book, Dissertation / PhD Thesis

In: Aachener Beiträge des ISEA 135
Page(s)/Article-Nr.: 1 Online-Ressource (XIII, 15-282 Seiten) : Illustrationen, Diagramme

Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2019


With an increasing share of fluctuating renewable energy generation the necessity arises for flexibility options in the electrical grid. Within a portfolio of options, battery energy storage systems (BESS) represent one solution. One major drawback of BESS is still their relatively high costs per kW and kWh. Hence, it is of interest to enable already installed battery systems to deliver services to the grid. The combination of several markets leads to an increase of possible monetary revenue and is defined as multi-use application. Industrial Uninterruptible Power Supply (UPS) systems are investigated as a valuable solution. Different UPS topologies are elaborated to identify the most suitable one for the above-mentioned purpose. Furthermore, a categorization of currently foreseeable applications within the German market as well as a detailed analysis of the most attractive opportunities is given. An equivalent electrical circuit (EEC) model with physically motivated sub-models is developed and parameterized for an UPS lead-acid battery to simulate its electrical characteristics under multi-use operation. The electrical model is coupled with an electrochemical aging model to evaluate the economic benefit of multi-use vs. stand-alone operation. The parameterization process is described in detail to facilitate the adaption of the model for other battery types. For the model implementation and diagnostic applications, the influence of the different aging mechanisms on the impedance spectra of a lead-acid battery is further investigated. This work is a contribution to enable UPS systems to deliver flexibilities to a future electrical network.