The Challenge
The G100 requirements of the Energy Networks Association regulate the maximum local PV grid feed-in within a grid area. Due to the decreasing electricity production costs of renewable energies, the installed generation capacity of PV systems in low-voltage grids is steadily increasing. However, many power grids are not yet dimensioned for the increased feed-in capacity. In order to continue to enable the expansion of decentralized power generation and at the same time ensure security of supply, there are so-called “export limiting schemes”. Typically, they specify that no electricity may flow via the substation into the upstream power grid. However, prosumers can share the electricity they produce among themselves in an energy community – provided that only the lowest grid level takes up the surplus PV electricity in each case. Therefore a central smart grid solution is required that manages the entire district, including all PV systems, consumers, and the grid operator’s substation in order to avoid a power flow out of the low-voltage power grid. For this purpose, the system has to curtail each single PV system in accordance to the power flow at the substation within five seconds. A communication infrastructure must be established between the households and respective inverters of the PV systems and the substation in order to monitor and control each single site.