The infrared temperature measurement technology is often used for detecting the terminal heating of composite insulator. Currently

in the process of measurement

the natural environmental factors

especially the environment humidity

plays an important role in effecting the measured results. Therefore

we statistically analyzed the recent 5 years data of infrared temperature measurement in Shenzhen

and studied the correlation between the environment humidity and measured value of temperature difference between the high-voltage and low-voltage terminals of the composite insulator under different environment relative humidity. Moreover

we analyzed the properties of composite insulator under different environment humidity by tests. The results show that

under the condition of higher environment relative humidity

the measured value of composite insulator will rise

the tangent value of dielectric loss angle gradually increases and trends to be saturated. According to the statistical data and test results

we recommend that the infrared temperature measurement shall be conducted when the environment humidity is lower than 67.5%.