How to test the attenuation rate of PV modules

author: Source

The component decay rate is the ratio of the component's initial power to the component's current maximum output power and the component's initial power. The key to calculating the attenuation rate is the measurement of the component's initial power and the component's current maximum output power.

The calculation formula is: attenuation rate = component initial power / (component initial power - component current maximum output power) * 100%

The initial power of the component is the maximum output power from the factory test of the component, which is obtained from the component factory laboratory solar simulator. The main factors affecting the factory test of the components are: 1) ambient temperature: controlled by air conditioning at 25 ± 2 ° C; 2) test equipment: solar simulator level requirement is AAA; 3) calibration and standard components: using calibrated standard component pairs The solar simulator is calibrated to correct the test results. 2

The current maximum output power of the component refers to the maximum output power measured after the component has been running for a period of time. The maximum output power of the test component itself should normally be excluded by factors such as dust occlusion and component defects. In the outdoor test component maximum output power, the main influencing factors are the following:

1) Test irradiance: For linear devices, the test should be performed at an irradiance of not less than 800 W/m2;

2) Test temperature: for the general backplane structure single glass component, the junction temperature reflects the battery junction temperature;

3) Solar spectrum: different regions and environments will have different solar spectra, and the accurate measurement should be corrected with the spectral value of AM 1.5;

4) Incident angle of the component: Different illumination angles affect the power generation performance of the component. The accuracy of the measurement should consider the influence of the incident angle on the test results.

5) Test equipment: Hand-held outdoor test equipment, used in conjunction with irradiation test and temperature test equipment;

6) Reference device: usually a well-packaged WPVS;

7) Test result correction: The outdoor irradiance and temperature are corrected to the results under STC conditions according to the IEC60891 standard.