A Novel Methodology for Partial Shading Diagnosis Using the Electrical Parameters of Photovoltaic Strings

Partial shading (PS) is inevitable during the outdoor operation of photovoltaic (PV) arrays. If not addressed appropriately, PS events will significantly reduce the output power and induce other severe issues, such as hot spotting. In addition, maintenance strategies should be designed according to the specific PS patterns, which are different from the measures for faults, for example, short circuiting. In this article, a novel PS diagnosis methodology is proposed to detect and classify shadings in PV strings, for which only electrical parameters are used. The impact of two common types of shading, static shading and variable shading, was studied in detail. The volatility and periodicity of the time series were utilized to achieve real-time monitoring instead of current–voltage measurements. The effectiveness of the proposed methodology was validated through experimental tests conducted on a PV system at Southeast University, China. The results demonstrate that the proposed method can effectively differentiate PS events from other faults and realize shading classification. Moreover, the application scenario for each technique was further illustrated through extensive tests, making the diagnosis and maintenance more efficient.