Fault diagnosis method and diagnosis equipment

Abstract

The invention provides a fault diagnosis method and diagnosis equipment, which are applied to the technical field of photovoltaic power generation. The method comprises the following steps of acquiring a high-irradiance IV data set and a low-irradiance IV data set of a diagnosis object, and taking any IV data set as a target IV data set, screening target IV data as inflection point data in the target IV data set, taking another IV data set as a reference IV data set, and screening IV data with the same voltage value corresponding to the target IV data in the reference IV data set as referenceIV data. And if the reference IV data also belong to the inflection point data, the mismatch type of the diagnosis object is determined according to the change result of the target IV data and the reference IV data along with the irradiance. According to the method, whether the mismatch fault of the diagnosis object is front current mismatch or back current mismatch is determined by analyzing theIV data under different irradiation conditions, so that decoupling of a fault judgment result of the diagnosis object is realized, and the accuracy of fault diagnosis is improved.

Description

technical field [0001] The invention relates to the technical field of photovoltaic power generation, in particular to a fault diagnosis method and diagnostic equipment. Background technique [0002] The IV data of photovoltaic modules or strings refers to the current-voltage data of photovoltaic modules or strings during operation. In practical applications, the corresponding IV data set can be obtained by performing IV scan on the photovoltaic module or string through the detection equipment. The data set includes multiple value pairs, each value pair consists of a current value, and the current value The voltage values ​​at the same sampling moment are formed. Since IV data can directly reflect the operating status of photovoltaic modules or strings, IV data is widely used in fault diagnosis of photovoltaic modules or strings. [0003] Most of the diagnostic methods in the prior art draw IV curves based on the test object, that is, the IV data set of the photovoltaic mo...

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Problems solved by technology

[0004] The inventors have found that for double-sided modules or strings, the IV data is the superimposed result of the output characteristics of the front and rear modules, and most of the commonly used diagnostic methods are based on the IV data of single-sided modules or strings. However, it only has good adaptability and diagnostic accuracy for single-sided components or strings. For double-sided components or strings, the existing diagnostic methods cannot determine the specific cause of the mismatch fault, that is, it is impossible to determine the cause of the mismatch fault. It is caused by the mismatch of the front current or the mismatch of the back current, which is difficult to meet the actual application requirements.

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