An Open Source Grid Observer for the Analysis of Power Flexibilities in Low Voltage Distribution Grid Simulations

The existence of voltage range violations represents a challenge in low voltage grids with a high penetration of decentralized generation, storage capacities or electro-mobility. If grid expansion is to be avoided in the future, an extensive information exchange between the system’s components is required to provide an optimal energy supply and guarantee operating requirements. This can be studied in details by modelling the energy system components and the communication between them, which is one of the aims of the research project "Future Energy Laboratories". Highly integrated application scenarios for sample districts in Germany are simulated and thoroughly analysed during the project. For the detection and correction of voltage range violations at individual buses of a grid, an Open Source Grid Observer tool was developed and tested as a flexibility feature in a quasi-dynamic energy system simulation of a residential district. It allows a wide range of compatibility between various simulation scenarios, as it gives recommendations for power control at considered buses according to predefined flexibilities, such as the type of power (active or reactive), flexibility components (e.g. generation and storage) and injection increment. The corrections were calculated using two methods of the voltage sensitivity analysis theory. A comparison between the methods’ robustness, accuracy and calculation speed is presented, being important performance factors to be considered in this kind of simulations. The functionality of the tool is demonstrated in scenarios with temporary peak loads from electric vehicle charging or a high share of distributed photovoltaic power generation.