Reduction method for planning cross-energy carrier networks in the cellular approach applicable for stability assessment in low-voltage networks

Abstract

Stability assessment for electrical networks is an essential research topic for sustainable energy generation and, therefore, future electrical networks. Renewable energy sources implemented in the grid in order to substitute fossil fuels as energy sources present a challenge for current network infrastructures since renewable energy sources are highly volatile and, therefore, not always predictable. Especially in low-voltage networks with high shares of PV penetration and extended network branches that supply customers with high consumption, power quality issues arise since these infrastructures were historically built to transport and distribute electrical energy from local substations to the consumers. Due to further developments and new consumer groups connected to the grid as well as generation in PV units, load flows may be reversed or enlarged leading to challenges in terms of overloads and voltage problems. In this work, a method for reducing electrical networks at the low-voltage level by applying the cellular approach is presented with special regard to power quality issues that may arise in low-voltage networks. Network reduction, in general, enables faster calculations of expanded networks with fine temporal resolution and can, therefore, be applied when handling large amounts of grid data. This methodology for network reduction within the cellular approach is implemented into a hybrid load flow calculation framework developed at the Chair of Energy Network Technology. The results obtained from the hybrid load flow calculation can then be used to show how hybrid flexibility options as well as storage units can help increase network stability (in this case regarding voltage stability).