Modification of Using Solar PV on-grid Inverter with Battery Unit

摘要

Solar PV plant is the lowest operation and maintenance renewable energy power plant. It contains only solar PV panel and Inverter either connects to the grid or store energy in the battery unit. The power policy of the regulator in Thailand is either sale power to the grid (On-grid) or using off-grid inverter with battery storage without connecting to the grid to avoid mixing of electric tariffs. However, in most potential area, high radiation of sunray, there are located in the rural area that has low capacity of grid cable feeder therefore the on- grid inverter cause over voltage tripping. If the off-grid inverter with battery unit is used instead, the daytime loading cannot be shared by the solar power. This paper propose the modification of the charge control circuit of on-grid inverter to share day-time loading with the solar PV and the rest of the solar power will store to the battery unit in order to avoid the over voltage tripping. The stored energy at the daytime will be used at the nighttime to maximize used of solar PV. The results show that the payback time is decreased. The optimization of load characteristic, cost of battery replacement, cost of utility network improvement, electric tariffs is also investigated.