Assessing the impact of RES on the grid of autonomous electrical systems using representative operation scenarios: the case of Chios Island

The incorporation of renewable energy sources (RES) in the power generation mix can be beneficial for the energy transition towards a cleaner energy mix, however, from a technical perspective, their connection to the grid is not without its drawbacks. Small-scale RES units that are dispersed along the distribution network are likely to provoke voltage and overloading issues, if their connection is not studied properly. To overcome such issues, distribution system operators (DSOs) should carry out detailed grid impact studies, which, in turn, require adequate data that in many cases are not available, and timeseries that are not always given in a granular chronological basis. In that context, DSOs should rely on the available data, even inadequate, to form representative, yet realistic scenarios to capture the coincidence of extreme conditions regarding load and distributed generation. This paper presents a comprehensive methodology that opts for representative scenarios to assess the operation of the medium voltage (MV) distribution network in autonomous electrical systems with increased RES penetration. The proposed methodology is applied to a real-world case, that of the distribution system of Chios Island, to resolve grid issues and to examine the hosting capacity of new hybrid power stations.