Capacitor voltage transformers is an important primary equipment of power transmission and transformation. For assuring safe and stable operation of CVT

the use of infrared technology for periodic test of CVT can time defect in time and also effectively prevent the accident of the equipment. In this paper

4 times of defects of the CVT found during the periodical test by the infrared detection technology are analyzed. It is shown by the result that electromagnetic unit in CVT prone to short circuit and poor insulation. The validity of the infrared detection is verified. The infrared detection experience is summarized and the daily preventive test and on line monitoring of capacitive voltage transformer is suggested.