Smart inverter and battery storage controls to reduce financial loss due to overvoltage-induced PV curtailment in distribution feeders

Abstract

The rapid growth of rooftop solar photovoltaic (PV) systems in low-voltage distribution networks has caused reverse power flow leading to voltage rise. As the voltage level increases, PV inverters first reduce the output power to regulate the voltage and may eventually shut down if the voltage level remains above the permissible limit. When this happens, the PV output power is curtailed, leading to financial loss. This paper examines two control strategies to reduce PV curtailment: (1) smart PV inverters and (2) residential battery storage system optimally sized to reduce the cost of household energy. Smart PV inverters can reduce the voltage level by absorbing reactive power at the expense of curtailing its active power output. Residential battery storage can reduce the voltage level by storing excess PV power instead of exporting it to the grid Using these two strategies, a systematic approach is presented to reduce PV curtailment and the associated financial loss. Three types of electricity tariffs are used, namely, electricity market pool price, and retail flat and time of use tariffs for household customers. An 11-kV distribution feeder in South Australia is analysed with the prevailing feeder and inverter voltage limits per Australian regulatory standards. The results demonstrate that installing 100% of PV systems with smart inverters and optimally sized battery storage can reduce the PV curtailment and the corresponding financial losses by 47%.