State identification and automatic control of smart low voltage grids

Due to the increasing installation of decentralized generation units and the increasing demand of electrical power on distribution level the low voltage grids in Europe are facing different problems, e.g. deviations of the permitted voltage range or local inner overloads of the grid equipment. To overcome these problems a self-sustaining monitoring and control system for low voltage grids has been developed, which monitors the actual power flow situation and controls individual decentralized generation units and consumer loads if necessary. In this context new approaches for power flow calculation and control intelligence are inevitable. This paper describes a newly developed power flow algorithm to be used for online-monitoring of the grid state. In case of critical grid states identified by this power flow algorithm a control intelligence determines and executes possible strategies for elimination of the critical grid state. The developed algorithms have been tested and validated in comprehensive scenarios in consideration of plausibility, calculation speed and reliability of the results.