Photovoltaic array fault defect diagnosis system and method

Abstract

The invention discloses a photovoltaic array fault defect diagnosis system and a photovoltaic array fault defect diagnosis method in the technical field of photovoltaic cell arrays. The method comprises the following steps: acquiring voltage and current values of each photovoltaic cell string in a photovoltaic array; the collected voltage values are compared, and the battery string with the minimum voltage value and the current and voltage values of the battery string are found out; calculating a difference value between the voltage value of the battery string with the minimum voltage value and the voltage value under normal operation, and judging whether the difference value exceeds a normal deviation or not; when the difference value does not exceed the normal deviation in response, the voltage and current values of each photovoltaic cell string in the photovoltaic array are collected again for continuous monitoring; and when the difference value exceeds the normal deviation, the battery string with the minimum voltage value is put into the suspected fault group for secondary fault battery string judgment. According to the invention, a traditional voltage and current positioning method, a time tracking method and a photovoltaic cell diagnosis model are combined, so that the type and the position of a fault can be basically judged.

Description

technical field [0001] The invention relates to a photovoltaic array fault defect diagnosis system and method, and belongs to the technical field of photovoltaic cell arrays. Background technique [0002] With the promotion of green energy, solar power generation technology has developed rapidly. The physical principle of solar power generation technology is to use the photovoltaic effect to convert the solar energy irradiated on the photovoltaic panel into direct current electric energy, and then convert it into various types of electric energy for the load to use through power electronic devices. In the process of solar power generation, photovoltaic cells are the core components in the power generation process. However, in the actual use of the photovoltaic panel, there will inevitably be obstacles such as birds, clouds, dust, etc., which will form partial shadows on the photovoltaic panel. In addition to the defects such as cracks and broken grids in the photovoltaic c...

AI Technical Summary

Problems solved by technology

The temperature difference between different cells in the photovoltaic panel of type A problems is not large, which is usually caused by the cracks of the cells caused by the handling and installation of the components. In the test of the indoor solar simulator, the power drop of this type of problem is about 5% to 8%. %; The failure of a single string battery in a photovoltaic panel with a Type B problem causes about 30% of the power loss. Usually, the components with a Type A problem have been operated outdoors for a long time, and the performance of a single string battery has failed after several months or longer. Converted to a component with a class B problem; a photovoltaic module with a class C problem causes a rapid rise in local temperature in a short period of time under a large reverse bias leakage current or reverse bias voltage, and the battery and panel are directly burned in a short period of time (a few days), This type of problem is mainly due to the current mismatch caused by shading or partial shading. At this time, the bypass diode is turned on and generates a lot of heat, and its performance decays and fails for a long time; after that, the photovoltaic cell will withstand higher reverse bias without protection. voltage, eventually causing the battery to burn out

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