State Identification Methods for Mv-grid Automation with Special Regard to Lv-interconnections

The utilization of power systems in Germany has changed considerably due to a fundamental shift in the variety of power generation during the last years. Since most of the renewable power plants are connected on distribution level, these grids are affected fundamentally. Smart distribution systems are one important element to handle the new challenges. Therefore the authors of the present paper are developing a decentralized automation concept for monitoring and control of MV-grids. Considering such a smart distribution system for MVgrids, it is most important to get a detailed overview of the current grid state almost in real time. Therefore, a reliable grid state identification is the primary requirement for any continuative surveillance or control method within the grid. An additional challenge of grid state identification within the German electricity network is a specific topology on the LV-level, which may have an influence on an autonomous MV-distribution system. In some distribution networks, there is a strong interconnection of MV-substations on the LV-level, which could be leading to power flows through the LV-grid and therefore influencing the voltage and currents in the MVgrid. The scope of the present paper is a comprehensive analysis of the impact of such LV-interconnections on the grid state identification for a decentralized MVautomation concept. A reasonable approach to enable an adequately accurate state identification in such cases has to be found. The superordinate scope of the research work is to develop an integrated automation system for LVand MV-grids, which enables an integrated smart distribution solution.