Temporary emergency power supply using medium-voltage islanded microgrids – a modular concept for distribution system operators

Abstract

Due to the continuous increase of distributed generation (DG) units at the distribution grid level, temporarily islanded microgrid (TIM) operation in case of a blackout becomes energetically feasible. DG units with black start capability and additional MVA-scale generation units in TIMs are a strong option for a fast intermediate supply. They create possibilities for a longer-term emergency supply for a large number of customers until the overall grid restoration (GR) is completed. To develop generalised concepts that are applicable for more than one individual medium-voltage grid, general requirements and conditions have to be analysed thoroughly and defined as generic as possible. Therefore, a modular concept is developed comprising individual modules for GR, energy management (EM), control, protection, communication and operation. The focus of this study is to present the developed modular concept with a special focus on EM and control approaches for TIMs. As a result, the exemplary application of the modular concept is successfully conducted. Finally, the modular concept provides recommendations for project planning and engineering for distribution system operators, which can easily be extended. Special requirements of the distribution grid operation can be defined and considered by this approach.