Detection method of pid using reverse saturation current and leakage current density of photovoltaic modules

Abstract

Using the PID method of reverse saturation current and leakage current density detection of photovoltaic modules, 1) Connect the solar cell module to the first power supply, and after applying voltage for several hours, test the reverse saturation current density and leakage current density respectively; 2) The test is completed Finally, connect the solar cell assembly with the fourth power supply, and after applying the voltage for several hours, carry out reverse saturation current density and leakage current density tests respectively; if step 1) the reverse saturation current density and leakage current density of the solar cell assembly are As the pressurization time of the first power supply increases, and the reverse saturation current density and leakage current density of the solar cell module in step 2) decrease with the pressurization time of the fourth power supply, the PID phenomenon occurs. The invention can accurately determine whether the PID effect occurs in the component, not only can realize early detection and early prevention of the built photovoltaic power station, but also can carry out online detection on the solar battery component before leaving the factory.

Description

technical field [0001] The invention belongs to the technical field of solar photovoltaic power generation, and relates to a method for detecting a PID by using reverse saturation current and leakage current density of a photovoltaic module. Background technique [0002] At present, solar photovoltaic power generation is the most promising form of power generation among renewable energy sources. However, the phenomenon of potential-induced attenuation (ie, PID effect) of photovoltaic module power attenuation caused by high system bias has frequently appeared in photovoltaic power plants in recent years. When PID is severe, it will cause the power generation capacity of the entire photovoltaic power station to drop significantly, or even be scrapped. Generally speaking, when the PID of crystalline silicon photovoltaic modules is relatively light, it can be recovered by applying reverse voltage, and the power can be restored to more than 95% of the output power before PID occu...

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Problems solved by technology

[0003] Although the method of testing the open circuit voltage of the module on-site at the power station can judge whether the PID effect has occurred on the module, this method cannot detect the PID in the early stage, and it can only be found when the PID phenomenon is serious. The test also has an impact, so this method is not accurate in the field test, especially it cannot be found in time in the early stage of PID, and it has already caused a large loss when it is found

[0004] The principle of using infrared thermal imager to detect PID on site is that the battery with PID phenomenon runs at a higher temperature than the normal battery. It shows a higher temperature than the solar cells with normal performance, so the detection method relying on the on-site infrared thermal imaging camera is not accurate, and this method cannot diagnose whether PID has occurred in the early stage of PID

[0005] The method of detecting PID by electroluminescence is to dismantle the components back to the room for testing. This method cannot distinguish the battery performance degradation caused by the PID effect from the battery performance degradation caused by other attenuation. Therefore, the method of detecting PID by using electroluminescence is also Inaccurate, and this method cannot diagnose whether PID has occurred in the early stage of PID

[0006] None of the above three existing PID detection methods can accurately detect whether PID occurs in the early stage. Therefore, in order to solve the common problems faced by the field of photovoltaic power generation, the present invention proposes the method of detecting PID by using reverse saturation current density and leakage current density of photovoltaic modules. method, when the reverse saturation current density and leakage current density of the component change in a few mA / cm2 and nanoampere / cm2 respectively, it can be judged whether the PID effect has occurred in the component. This method is accurate and sensitive.

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