A Thai National Demonstration Project on PV grid-interactive systems: power quality observation

We report here the first results obtained from a 4.2 kWp PV grid-connected system installed at a secondary school under a Thai national demonstration project on PV grid-interactive systems. The power quality of system output as a function of radiation and its load are monitored. The power quality parameters measured are the complex, active and reactive power, the power factor, the voltage and the current of each harmonic and the total harmonic distortion. It is found that the inverter supplies power of low quality at low solar radiation level. Low solar radiation results in correspondingly low PV output and inverter output power in comparison with its rated power. Under this operating condition, the inverter exhibits large non-linearity.