A study of the automatic analysis for the I-V curves of a photovoltaic subarray

The authors are studying a diagnostic method of a PV array by utilizing the I-V curve. In this paper, the standard dI/dV-V curve obtained by the I-V curve of normal PV subarray is decided as the standard characteristic for the automatic analysis. This dI/dV-V curve is used to compare with dI/dV-V curves of abnormal shaped I-V curves such as the PV subarray with partial shadow. The dI/dV-V curve of abnormal PV subarray is remarkably different from the standard dI/dV-V curve. And the variance value to evaluate the difference between the standard dI/dV-V curve and the abnormal dI/dV-V curve is calculated. It is clear that the degradation of generating power characteristics of PV subarray can be analyzed by the variance value quantitatively.