Allowing islanded operation of photovoltaic system with the aid of droop-controlled inverter

Under existing regulatory framework, islanded operation of renewable energy sources is not allowed. This is because the voltage and frequency of an islanded network can´t be regulated. As a result, the available renewable energy cannot be utilized during the outage of the main grid. Therefore, it is beneficial if the renewable energy sources can continue to supply without any voltage and frequency violation during islanded operation. In this paper, islanded operation of photovoltaic systems is enabled with the aid of a droop controlled bidirectional inverter. A control algorithm is developed to control the inverter so that it is able to stabilize the voltage and frequency by minimizing the power mismatch at the inception of islanding, allowing the photovoltaic systems to operate in the islanded mode. The experimental results show that the proposed solution allows the photovoltaic system to operate effectively without posing any voltage and frequency violations during islanded operation.