The rapid growth of grid-connected photovoltaic (PV) systems in low-voltage distribution networks has transformed traditional one-way electricity grids into two-flow power systems. During periods of high solar irradiance and low consumption locally, maximum power from residential PV systems causes voltage fluctuations. If these fluctuations become too high, they risk damaging components and compromising grid stability. This thesis investigates the technical and economic value of active power curtailment (Volt-Watt-control) in low-voltage networks as an alternative to physical grid upgrades, seen from both Ellevio’s and the customers' perspective.

The methodology is based on power flow simulations conducted in the Python-based tool Pandapower. The simulations were inspired by three networks owned by Ellevio. Real microproduction data was used. To investigate the problem in critical conditions, the production data was scaled to reflect maximum installed capacity during low load summer times. Two different active power curtailment settings were implemented and evaluated. Additionally, an economic assessment framework was developed to calculate financial loss for customers and compare it to grid reinforcement costs.

The simulation results show that active power curtailment is a good technical method for maintaining grid voltage within safe regulatory limits. The 7 percent curtailment threshold was found to be the superior operational configuration. It preserves grid stability while minimizing unnecessary production losses for customers. Economically, implementing this control strategy allows Ellevio to significantly postpone large investments in physical cables, since the cost for compensation for customers remains marginal compared to physical cable replacement. However, the curtailment affects customers unequally depending on their location in the grid. This creates a challenge with fairness that needs a simplified compensation model to be solved.