Abstract:

The increased active power injection of the grid-connected Photovoltaic (PV) inverters has led to some challenges in the power quality issues. The PV inverters have been recommended in the technical standard requirements in order to control the reactive power supply into the grid. The purpose of this study is to investigate the correlation of the power factors to total harmonics distortion in a 30 kWp grid-connected PV inverter using two different operating modes. This research presents analyses of the statistical results of power quality parameters such as the changes in relative and reactive power, THD on current and voltage, and harmonic components of current and inverter voltage at different loads. The power quality parameters is assessed by using the Var regulation based on a constant power factor (CPF) and compared with the Var regulation based on changes in grid voltage (Q(U)). The unity and non-unity PF is simulated with high and low capacitive level. The results showed that THDi and THDv were less than 5% when the inverter approached nominal power. The non-unity PF constant inverter produces lower harmonic distortion than the unity PF. The simulation results found that the harmonic component of the current increased by more than 7% in the 7th order when the active power was less than 9% of the nominal power. However, reactive power regulation is proportionally constrained to prevent overvoltage of the inverter. The presented results are useful in fulfilling the technical requirements associated with the operating mode of the grid-connected PV inverters.

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