Measuring the voltage distribution (or zero checks) of suspension insulators and multi-element pillar insulator strings is one of the methods to check for degraded insulators. It is carried out without power failure.
(1) Characteristics of voltage distribution on the insulator string
The voltage that each element in the suspension insulator string bears is different. This is mainly due to the capacitance between the metal part of the insulator and the ground, the cross arm or the tower, and the point wire, which makes the voltage distribution of the insulator string Very uneven. The voltage drop on the insulators closer to the wire in the insulator string increases, and the voltage on the insulators farther away from the wire gradually decreases, but the voltage drop of the insulators close to the cross-arm increases again, and the more the number of insulators, the greater the voltage distribution The more uneven.
(2) Inferior insulators and their treatment
If one or several insulators on the insulator string are degraded, the voltage distribution on each insulator along the insulator string will be different from the normal voltage distribution. If the degraded insulator has been conducting through electricity, the voltage across the insulator will be zero (called a zero-value insulator). If the insulator deteriorates, the voltage on it will be reduced, and the reduced voltage will be transferred to other insulators, especially the nearby insulators, thereby reducing the electrical withstand capability of the entire insulator string. Therefore, it should be checked and replaced in time. Commonly used tools such as resistance distribution rod, capacitance distribution rod, and spark gap inspection rod for measurement.