Methodology for detection of photovoltaic systems underperformance operation based on the correlation of irradiance estimates of neighboring systems

Abstract

The methodology for the detection of under-performance operation of neighbouring photovoltaic systems is presented. The methodology compares the estimations of the total horizontal solar irradiance obtained from a group of photovoltaic systems. The estimations can be obtained from the direct measurement of the solar irradiance or indirectly by utilizing the group of methods for the processing of electrical signals at the output of the photovoltaic system. Inter-system comparison is performed solely during the system operation under the detected clear-sky conditions, as this atmospheric condition in a predictable manner affects the incident solar irradiance at the arbitrary surface area. We assume that the measurement or the estimation of the total horizontal solar irradiance in close proximity area under the particular clear-sky condition is expected to produce comparable results. In order to provide the comparable estimations, the methodology introduces the system efficiency factor to address various influences on the operation of the photovoltaic system, which are not easily addressable in analytical form. These influences are related to different physical, installation, and operational properties of the photovoltaic system, including aging, manufacturing tolerances, and other technology-related properties. The methods for the empirical assessment of the system efficiency factor as well as for the correlation-related processing are also given as a part of the proposed methodology. The utilization of the methodology for the detection of the under-performance operation is verified through the presented case study.