Distribution line structure and generation efficiency improvement: A clustered residential grid-interconnected PV

In Japan, the target capacity for installed photovoltaic power systems (PV) in 2020 has been set to 28 GW. The PV output (active power) must be suppressed to sustain adequate voltage (within 101 ± 6V), which was established by the Electricity Business Act in Japan, due to voltage increases by inverse power from PV when clustered residential PV systems are grid-interconnected on a distribution line, even if sufficient irradiance exists. Simulation software was developed to analyze voltage increases when clustered PV were grid-interconnected on a large-scale demonstrative research in Ota City, Japan. From the previous fiscal year, the authors started to research improving whole generation efficiency at a site. We are developing to balance it among all the residences through voltage control, including power conditioning systems of a clustered residential grid-interconnected PV with the developed simulation software. For the subject, we have already demonstrated that 25 percent of the output suppression loss was eliminated with reactive power control when 225 residential PV are grid-interconnected to a simple single distribution line. In this research, a complex single distribution line, where 2160 residential PV are grid-interconnected, is set. We develop suitable voltage control for both simple and complex distribution lines.