Investigating the Impact of Different Operational Strategies for DC Links in Medium-Voltage Grids

The demand for grid expansion in medium-voltage grids is expected to increase due to the growing penetration of decentralized generation plants and new types of power consumers. In addition to the conventional expansion of medium-voltage grids, an alternative expansion with DC links is possible, which provides additional flexibility through an active and reactive power flow control capability. During the planning and operation of these DC links, suitable operational strategies are required to determine optimized set points for the corresponding AC/DC converters. In this paper, different operational strategies of DC links in medium-voltage grids are investigated by different formulations of an optimal power flow problem. For this purpose, technical aspects such as current and voltage limits as well as grid losses are investigated.