Increase of photovoltaic (PV) systems penetration in distribution networks is being challenged by technical barriers, especially in low voltage (LV) networks, such as over-voltages caused by reverse power flows and high PV power injection to the grid. Among other solutions for over-voltage mitigation, active power management can be a highly effective method in LV feeders. However, such methods usually curtail the excess power resulting in a loss of clean and renewable energy and do not take into account the interaction of a prosumer with the grid. To deal with that, this paper proposes a novel active power management methodology for over-voltage mitigation in active LV networks. The methodology calculates the maximum allowed amount of injected power to the grid at each time instant of the day and generates an active power management schedule for the prosumers based on their self-consumption ratio (SCR). This schedule allows prosumers to choose whether to employ either controllable loads or storage systems to manage the generated energy. In this way, injected power to the grid is efficiently handled and over-voltage mitigation is ensured, while the permissible level of PV penetration is increased without requiring large investments by the network operator. The proposed methodology is examined on a LV test network and is compared to other existing techniques for feeder voltage support. The results show that the application of the methodology increases SCR of installations, treating at the same time prosumers in a fairer way compared to existing methods.