Low voltage distribution networks incorporating solar photovoltaic (PV) panels experience overvoltage and voltage unbalance during periods of low load and high PV generation. Resolving overvoltage by active power curtailment (APC) is an effective and cost-efficient solution. However, current APC techniques result in excessive and unfair power curtailment for prosumers at the sensitive parts of the grid that might induce neutral current. In this work, an analytical approach for fair APC and Reactive Power Control is presented for voltage regulation along with neutral current compensation. The desired power quality is maintained by controlling each phase of the PV inverter independently. The proposed algorithm regulates the voltage at the point of common coupling (PCC) within grid limits, eliminates neutral current, and reduces the grid unbalance. Furthermore, the results demonstrate that reducing the neutral current reduces the voltage at the PCC and consequently decreases the power curtailment required for overvoltage regulation.

With the increasing adoption rate of electric vehicles, power peaks caused by many cars simultaneously charging on the same low-voltage grid can cause local overloading and power outages. Smart charging solutions should spread this load, but there is a residual risk of incidental peaks. A decentralized and autonomous technology called GridShield is being developed to reduce the likelihood of a transformer’s fuse blowing when other congestion solutions have failed. It serves as a measure of last resort to protect the grid against local power failures from unpredicted congestion by temporarily limiting the virtual capacity of charging stations. This paper describes the technical development and demonstrates how GridShield can keep a transformer load below a critical limit using simulations and real-world tests. It optimizes grid capacity while ensuring grid reliability.

Driven by the effects of climate change, our world is in a rapid transition towards a sustainable society powered by renewable energy, such as produced by solar panels and wind turbines. As a result, the supply of energy becomes less controllable, endangering the stability of the electricity system. On the other hand, the adoption of electric vehicles and heat pumps also provides an opportunity to avoid overloading as electricity can be produced and consumed locally. The scope of this thesis is to perform decentralized energy management, specifically within residential distribution grids where large scale adoption of distributed energy resources (DERs) is expected. A cyber-physical systems approach is taken to study the interaction between control systems, the operation of devices and the effect on the physical grid. The first contribution is a proactive control methodology called profile steering to decentralize the coordination between all DERs in a microgrid. The hierarchical structure of profile steering allows for a natural mapping between and radially operated low voltage grids. The model predictive nature of this approach resolves prediction errors in both the time and energy domain. A second contribution is a control methodology based on double-sided auctions, for real-time balancing in islanding situations. In such situations, DERs can assist conventional backup solutions in balancing a microgrid. Local information can be used to avoid overloading when communication networks fail. The third contribution is the developed simulation and demonstration framework to test these control methodologies in a cyber-physical systems context. A real-life stress-test resulted in a supply interruption due to grid overloading. The lack of controllability was a major cause for this, illustrating the importance of control in future distribution grids. The presented decentralized energy management approach is a valuable tool to unlock flexibility of DERs and provide means for a smooth energy transition