Coordinated Voltage Control of Microgrids With Integrated Electric Vehicles in Real-World Experiment and Application: Industrial Design and Implementation on EUREF-Campus in Berlin

A coordinated voltage control algorithm is developed to facilitate the integration of electric vehicles into microgrids. This proposed algorithm reduces the voltage fluctuations via the optimal adjustment of the tap positions of on-load tap changers and of the reactive power injections of inverter-based distributed energy resources. Based on the proposed voltage control algorithm, an industrial implementation framework is established to enable the interactive communications among the on-load tap changers, the inverter-based distributed energy resources, etc. Compared to previous studies on voltage regulation in microgrids, this work is distinguished by the fact that the proposed voltage control algorithm is implemented and tested on a real-world experimental test site, known as the micro smart grid on the EUREF-Campus in Berlin. Constraints, such as actual process latencies are readily observed. The micro smart grid comprises a power transformer with on-load tap changer, rooftop photovoltaic systems, battery energy storage systems, and electric vehicle charging stations. The real-world test results confirm that the voltage deviations are significantly reduced by the coordinated voltage control algorithm, as opposed to the uncontrolled state. Thanks to the analysis of the trigger cycle of the proposed algorithm, the lifetime of the on-load tap changer can be extended while ensuring the effectiveness of voltage control.