High reactive power fluctuations in Low-Voltage (LV) distribution systems may negatively impact the power quality of the electrical network in a variety of ways. In this paper, a novel multi-objective optimal power flow (OPF) formulation is developed to smooth the reactive power fluctuations caused by photovoltaic (PV) inverters in central voltage-control strategies for LV distribution networks with high PV penetration. The proposed multi-objective optimization methodology includes a minimization of the violations to a dead filter-based band to smooth them. Results show that while a typical Voltage Rise Minimization (VRM) optimal method and local Q(U) method have similar behaviour with high reactive output power fluctuations, the proposed method significantly outperforms these two methodologies smoothing the reactive fluctuations until a 75% achieving the optimal control goals set.