Current injection disturbance based voltage drift control for anti-islanding of photovoltaic inverter system

Islanding detection is necessary as it causes power quality issues, equipment damage and personnel hazards. This paper proposes a new active anti-islanding scheme for inverter based photovoltaic system connected to grid. This method is based on injecting a current disturbance at the PV inverter output and observing the behavior of voltage at the point of common coupling (PCC) in absence of grid which depends upon the load connected to the PV inverter in an island condition. The proposed control scheme is based on Synchronous Reference Frame or dq frame. The voltage drift scheme using control gain and current command reference as positive feedback is utilized to drift the PCC voltage beyond the threshold limits to detect island within 2 seconds as prescribed by IEEE 1547. The test system configuration and parameters for anti-islanding study is prepared on IEEE 929 standards. The proposed control scheme is implemented on constant power controlled inverter system with reliable islanding detection. The effectiveness of proposed anti-islanding scheme is validated by extensive simulation done in MATLAB platform.