GridShield: A Robust Fall-Back Control Mechanism for Congestion Management in Distribution Grids

The growing number of electric vehicles (EVs) in the low-voltage distribution grid increases the load and thereby the risk of overloading and damaging grid assets. Since energy management systems designed for controlling electric vehicle charging can fail, e.g. due to cyber attacks or failure of communication systems, a robust fall-back control mechanism is required to prevent congestion and overloading problems in the grid. This paper presents three variants of such fall-back control mechanisms and evaluates them using a simulation of a Dutch neighbourhood. Comparison of the three strategies with respect to power limit violations and energy not served to EVs shows that all strategies significantly reduce power limit violations, while the energy not served is less than 21% of the energy served in the base case without control. The AIAD (additive increase, additive decrease) and AIMD (additive increase, multiplicative decrease) strategies achieve similar reductions of total power limit violations, 84.1% and 84.6% respectively, while an optimized PID based controller performs considerably worse with 55.9%.