Disaggregating solar generation from feeder-level measurements

Photovoltaic (PV) systems are increasing in distribution systems, but utilities lack visibility of the generation of this distributed PV. This paper presents a set of methods for disaggregating the photovoltaic (PV) generation downstream of a measurement device that measures net load using only readily available measurements. We propose two strategies in which we use measurements from the substation as well as a proxy solar irradiance measurement. Using these two measurement points, we first propose a multiple linear regression strategy. We estimate a relationship between the measured reactive power and the load active power consumption, which are then used in real-time disaggregation. Then, we expand this strategy to reconstruct the errors in the estimators, thus separating the solar and load signals from their aggregate. We show that it is possible to disaggregate the generation of a 7.5 megawatt photovoltaic site with a root-mean-squared error of ≈ 450 kilowatts.