Methodology and Instrumentation Development for a Solar Module Diagnosing System in a Remote Mode under Non-Uniform Illuminaion

Abstract

The monitoring principle of the solar module conditions as a part of photovoltaic power plants is considered. In the existing monitoring technology, information about the electrical parameters of individual solar modules being the part of linear chains gets lost. If a fault is not detected and corrected in a timely manner, energy production is reduced and the risk of local hot spot formation in the photovoltaic converters that make up the solar modules increases. The technical task is to equip the solar module with a diagnostic unit simple in design and capable to detect a violation of the normal operating mode automatically. A system for diagnosing solar modules in a remote mode has been developed, which determines the presence of current in the bypass diode circuit being the violation of the normal operation mode of the module. The current sensor (based on the Hall effect) detects the presence of current in the bypass diode circuit (i.e., current flowing bypassing a group of solar cells located at reduced illumination). This installation makes it possible to detect electric current in the bypass diode circuit, where it should not exist during normal operation, which is a consequence of the fact that the solar module group of solar cells shunted by this bypass diode has stopped generating electric current, due to the fact that the illumination of one or several PV cells in this group became lower than the PV illumination in other groups of the solar module. The diagnostic unit operates as part of a wireless sensor network. Each wireless diagnostic unit has a unique address, thanks to which it is possible to determine the coordinates of a module that is operating intermittently. The technical result is to simplify the design, increase the reliability of the solar module, and reduce the time for localizing the “problem module”.