9 Intermittency ramp rates and timescales analysis

To demonstrate the effect of rapid fluctuations in solar radiation on PV systems, ten months of data from the Desert Knowledge Australia Solar Centre (DKASC), Australia, was obtained and analysed. The 10-second sampled data includes the irradiance and power output at the same site. The data also includes the average line-to-neutral voltage of the three phases at a centralised switchboard measured using a class 0.5 ION 7550 energy meter. The main feeder connecting the Solar Centre to the nearest substation is approximately 350 metres long and connected from a 22kV step-down transformer. The PV system at DKASC can be considered a medium-scale installation among all currently existing and operating PV systems in Australia. To analyse PV power output ramp rates for a small-scale system and also a large-scale system in Australia, data was obtained for a 22 kW PV system at the CSIRO Newcastle site with 5-second resolution and for a 1.22 MW PV system at the University of Queensland (UQ) (currently the largest flat-panel PV solar power system in Australia) with 1-minute resolution.