Application Experiences of Low Voltage Inline Voltage Regulator with Significant Photovoltaic Generation

Renewable energy generation is spreading apace worldwide, bringing integration challenges for distribution system operators. The focus of this study is to investigate the possible solutions to increase the hosting capacity of an actual low voltage (LV) feeder in Hungary. This pilot site already has significant photovoltaic (PV) generation, but more installations are expected in the near future. Simulations were carried out to compare the available technical options increasing the hosting capacity. Detailed on-site measurements were taken, which included the neutral line, to have a better understanding of the basic situation. It showed that the voltage is close to the limits with significant unbalance. Therefore, an unbalanced model was adopted with a new calculation method in order to incorporate the neutral line and the groundings. The simulations compared local PV inverter control, inline voltage regulator, tap-changing transformer and phase balancer and found the inline voltage regulator as the most effective and versatile solution for this case. A new device was developed and installed that implements an inline voltage regulator, optimized for local circumstances. Then, a longer series of measurements were taken which proved the effectiveness of the unit, showing that it can be a cost-effective grid development alternative to grid reinforcement.