Reactive Power Provision with Distributed Energy Resources: Limitations, Potentials and Losses

Presently, reactive power is mainly provided by conventional power plants. As the utilization of these sources decreases, alternatives must be found. Generally, variable renewable energy power plants can be used to provide reactive power for the grid but the utilization possess several challenges. In this work, the limitations of reactive power supply with these sources are investigated and described. Besides the limitations, the resulting additional losses and thus the operating costs are essential for the assessment of the economic efficiency of these sources in comparison to other reactive power sources. In a case study of a real power plant, both aspects are examined in greater detail. The results show that a detailed model of variable renewable energy power plants is necessary to assess both effects accurately. The use of constant loss factors can lead to an incorrect economic evaluation and thus to erroneous conclusions.