Balancing the grid with single-phase PV-installations

Many state of the art voltage control algorithms aim at reducing voltage rise in distribution grids caused by distributed in-feed, e.g. Photovoltaics (PV), by reactive power control strategies or active power curtailment. Due to the R/X-ratio, the effectiveness of reactive power on the voltage is generally more effective in medium voltage networks (MV) compared to low voltage networks (LV). For small scale single-phase PV-installations in low voltage networks, an approach to reduce the voltage rise is presented. Instead of reactive power control, the 3 phase-neutral voltages are monitored and the phase assignment of single-phase DER-installations is changed on the fly during operation to switch to the phase with the highest demand. This approach increases the amount of locally injected power that is consumed by nearby customers. Hence, losses in the LV-network and reverse power flows to the upstream MV-grid are reduced.