Estimation of a simple model of solar power generation using partial information

Abstract

This paper presents a heuristic method for the estimation of a model of a photovoltaic plant to be used for power generation forecasting purposes. The problem is addressed in a scenario where measurements of meteorological variables (i.e., irradiance and temperature) at the plant site are not available. The proposed approach efficiently exploits only power generation measurements and theoretical clear-sky irradiance, and is characterized by very low computational effort. A real-world application is presented to validate the procedure, which is also currently in pre-deployment phase at a Distribution System Operator control center in Northern Italy

Estimation of photovoltaic generation forecasting models using limited information

“…The information contained in such portions is then exploited in a recursive parameter estimation algorithm in combination with theoretical clear-sky irradiance provided by a suitable model. The method proposed in this paper improves over [26,27,29], since it is able to adapt to parameter variations and requires the tuning of a single threshold coefficient whose physical role can be interpreted in terms of the cloud cover factor (CCF) [31].…”

“…• As previously stated, a good guess for the main power/irradiance gain µ 1 is represented bŷ µ 1 (0) = P nom /1000, where P nom denotes the nominal plant power [24,27]. As pointed out in Remark 1, it is appropriate to start with an underestimate of this value, e.g., 75%, to ensure faster parameter adaptation.…”

“…In order to estimate model parameters, replacing the measured values of I and T with forecasts Î and T provided by a meteorological service is not a viable solution, due to the fact that forecasting errors on the irradiance are in general too large. On the contrary, temperature forecasts are quite reliable and can be used in place of actual measurements (see [26,27] for details).…”

“…In these approaches, however, further information on the cloud cover index at the plant site is assumed to be available. In [26,27], a heuristic method for the estimation of the parameters of well-known PVUSA model [28] based on theoretical clear-sky irradiance is presented, while in [29], a recursive procedure based on the clear-sky criteria proposed in [30] is devised. However, the former approach does not allow for capturing possible parameter variations or seasonal drifts, and moreover both approaches require trial-and-error in order to manually tune a number of algorithm parameters whose values may vary significantly according to the climate zone.…”

Model estimation for solar generation forecasting using cloud cover data

“…In [19,20], two methods are proposed to estimate the parameters of the PVUSA model [21] of a PV plant via a recursive framework based only on measures of generated power and temperature forecasts. This solution is not always data-efficient, since generation data collected during cloudy days are not exploited.…”