Test Scenario 1

Test Date: September 2025

Test Location: A centralized photovoltaic power station in Qinghai, with an altitude of approximately 3000 meters

Time: 9:30 – 19:00

Weather: Cloudy   Temperature: 10℃ – 23℃    Humidity: 66%

組件1（N型）-測試時(shí)陽光直射
PL
The module is damaged and cannot be powered on, rendering the EL test invalid.
組件2（N型）-測試時(shí)陽光直射
PL
The module is damaged and cannot be powered on, rendering the EL test invalid.
組件3（N型）-測試時(shí)陽光直射
EL
PL
組件4（N型）-表面玻璃碎裂-測試時(shí)陽光直射
EL
PL
組件5（TOPCON）-測試時(shí)有薄云層
EL
PL
組件6(N型)-測試時(shí)有薄云層
EL
PL
組件7（多晶）
EL

Test Scenario 2

Test Date: September 2025

Test Location: A distributed photovoltaic power station in Qinghai, with an altitude of approximately 2000 meters

Time: 11：00~12：00

Weather:Sunny with direct sunlight     Temperature: 20℃ – 22℃    Humidity:51%

組件1（BC）

EL

PL

組件2（單晶PERC）

EL

Test Scenario 3

Test Date: August 2025

Test Location: A rooftop distributed photovoltaic power station in Jiangsu, with an altitude of approximately 100 meters

Time: 17：00~18：00

Weather:Overcast    Temperature:35℃    Humidity:80%

Irradiance：40w/m²

檢測最下方一排組件PL，組件如下圖：

檢測結(jié)果統(tǒng)計(jì)表：

Total Number of Inspections	23
Number of Modules with Microcracks	5
Detection Rate of Modules with Microcracks	21.74%
Total Number of Microcracks	9
Module1-2：Number of Microcracks（0）
Module3-4：Module3 Microcracks（5），Module4 Microcracks（1）
Module5-6：Module5 Microcracks（1）
Module7-8：Microcracks（0）
Module9-10：Microcracks（0）
Module11-12：Microcracks（1）
Module13-14：Microcracks（0）
Module15-16：Microcracks（0）
Module17-18：Microcracks（0）
Module19-20：Microcracks（0）
Module21-22：Microcracks（1）
Module23：Microcracks（0）

Conclusion：

 Tests on various types of PV modules for PL and EL were conducted at centralized and distributed photovoltaic power stations located in Qinghai (plateau region) and Jiangsu (plain region). The tests covered different environmental conditions including direct sunlight and cloud cover, as well as different time periods such as morning, noon, afternoon and dusk. A wide range of defects were detectable, including virtual soldering, microcracks, bypass diode failure, contamination and scratches.

Adventage：

Daytime EL/PL testing is safer and more efficient than nighttime testing. This advantage is even more pronounced for centralized power stations located in wilderness areas, mountainous regions, on water surfaces and in low-lying lands, as well as for distributed power stations installed on high-rise rooftops.

During the construction phase of power stations, daytime EL/PL testing enables convenient random inspection of incoming modules outdoors in daylight hours, eliminating the need for testing at night or in indoor darkrooms.