Identification of typical quality control issues in distributed PV power measurements

Distributed PV power output measurements and their metadata are subject to significant errors and uncertainty. However, no standard mechanism for quality controlling these data is currently available within the literature. For this purpose, we present a two part approach to parameterize PV system metadata and quality control their power output measurements. These methods are based on open-source solver routines and require only one exogenous input (ambient temperature) besides the power output measurements, and therefore are widely applicable. The central routine, entitled QCPV, imposes physical limits on the measured data through the use of the extraterrestrial radiation and the clear sky index for photovoltaics Kpv. It also enables detection of cloud enhancement events and spurious power output reporting through the application of "across-systems" statistics. The method allows for PV array orientation to be determined to within ~ 4°, and has found most erroneous data to be located at elevated Kpv values, at increased zenith angles and also for values near zero.