Abstract: One of the existing most popular technologies for finding open bypass circuits to prevent hotspots is the measurement of surface temperature with an IR camera. However, this solution has defects. For example, the thermal image is affected by the reflection of surrounding structures such as antennas and buildings, and so on, and it is difficult to measure the true surface temperature of PV modules with an IR camera. To solve the problems mentioned previously, we developed new detection technology for open-fault bypass circuits. The stationary state reflection effect is deleted, and the position of the open fault part is identified exactly by the development technology. However, the reflection effect of moving clouds is not deleted. Therefore, we studied the advanced detection technology to delete the reflection effect of moving clouds. In this paper, the outline and effect of a new proposed technology is described.