Optimal Placement and Sizing of Battery Storage to Increase the Pv Hosting Capacity of Low Voltage Grids

The purpose of this thesis is to investigate the cost-optimal placement and sizing of battery storage as a PV integration measure in the distribution grid level. Additionally, potential synergies between PV generation, battery storage, smart PV curtailment and electric mobility are also explored within this thesis. Accordingly, a versatile optimization tool has been developed in order to identify potential battery location and size combinations that increase the PV hosting capacity of a low voltage grid at minimum cost. The optimization tool is based on the two basic Optimal Power Flow (OPF) algorithms: AC OPF and DC OPF. The high computation times that an AC OPF requires, as well as the many simplifications assumed in the DC OPF, necessitate the development of hybrid methods that render the optimization problem tractable without neglecting crucial operational data (e.g. voltages). In the project PV Leimbach, ewz compares potential PV integration measures on a technical as well as economic basis. In this context, one substation area of Leimbach is chosen for the demonstration of the optimization tool in a real network. Measurement data from a local transformer station and PV plants in the city of Zurich for 2013 are utilized as inputs for the optimization. Moreover, scenarios including electric mobility load curves extracted by a model developed at ETH Zurich are also investigated. The functionality and the performance of the developed methods is assessed for a benchmark network of reduced size and a single method that provides the best trade-off between computational time efficiency and accuracy of the results is chosen for implementation on the real case-study network. The cost optimal battery storage placement and sizing is investigated, while the battery storage dispatch is assessed by a second optimization algorithm that aims at the maximization of the degree of self-sufficiency of the LV grid area. In the second part of the simulations, various sensitivity analyses are carried out to investigate different scenarios and parameter combinations. The results of this work show that a DSO would have to bear considerable costs in case the problems caused by PV penetration are addressed exclusively by battery storage installation. The implementation of even low curtailment levels could result to a drastic reduction of these costs with negligible energy losses. Assuming a high PV penetration, a similar reduction of the required battery capacity results with the introduction of a high share of electric cars. Finally, it can be concluded that the implementation of hybrid AC and DC OPF methods for battery placement and sizing problems can lead to