Online detecting composite insulators by two dimensions electric field distribution

Electric field method is one of the most efficient methods to find conductive defects on composite insulators. This method has already been used in many places including China. If there is a defect on an insulator, the distribution of the electric field along the insulator contrasts with that of a good insulator. The electric fields covered in this paper include that along the axis direction of the insulators, that on the radial direction of the insulators and the synthetic electric field. The characteristics and sensitivity of each kind of electric field distribution along the insulators were studied by experiments in the laboratory to detect defects at the high voltage part and the middle part of insulators. It was found that the electric field along the axis direction is more sensitive to defects at the high voltage part of the insulator and can find 5 cm defects when the insulator does not have a corona ring. The electric field in the radial direction can find 10 cm defects at the middle part and 5 cm defects at the high voltage part when the insulator has a corona ring