As part of the Aspern Smart City Research (ASCR) energy research project, Wiener Netze and Siemens Austria researched the integration of e-mobility charging infrastructure into urban low-voltage grids. The team examined five different planning and operating strategies for the charging infrastructure of a typical urban low-voltage grid section. The focus was primarily on solution scenarios that do not require grid reinforcement. These range from current static processes to innovative operating modes in which dynamic operating envelopes (OEs) are also used. The research results were presented at this year’s CIRED conference in Geneva.

A typical urban low-voltage grid with a very high capacity utilization was used for the simulations. Actual grid bottlenecks were determined on the basis of real-time data and the complete fulfillment of the charging capacity was ensured in a grid-compatible manner by flexibly adjusting the charging capacity. “The rapid increase in electric vehicles poses a major challenge for the existing electricity grid infrastructure. The aim of our research project is to make optimum use of the available capacities and ensure the security of the grid through grid capacity management. Transparency in the distribution grid is absolutely essential for this,” says Alfred Einfalt, Principal Key Expert at Siemens, who co-initiated the associated project.

Operating envelopes as dynamic performance limits

By introducing OEs as dynamic power limits for charging facilities based on real-time data, the number of charging points for electric vehicles could be increased around sevenfold in the simulation scenario – without any grid expansion. In addition, a scenario was also examined in which the strategic use of the n-1 reserve capacity is released for public fast-charging facilities. N-1 is a central criterion in grid planning that ensures that a power grid can compensate for the failure of individual components by “filling in” for other components. Power outages can thus be reduced and their duration shortened.

The results show that dynamic grid capacity management can significantly improve the efficiency and utilization of the electricity grid – and that intelligent planning and control of electromobility make an important contribution to the energy transition. The next step is to test the research results in the ASCR test area in aspern Seestadt. The SENSE project was funded by the Austrian Research Promotion Agency (FFG) and the Federal Ministry for Climate Protection, Environment, Energy, Mobility, Innovation and Technology (BMK).

Siemens offers various solutions to enable grid operators to better monitor their low-voltage grids and thus optimize grid operation. These include the Gridscale X LV Insights software solution and the SICAM EGS sensor.