Analysis Of The Causes Of Flashover Discharge In Copper Terminal Blocks

Flashover discharge is an electrical breakdown phenomenon that occurs along the surface of insulation or across air gaps. Its essence is that the dielectric becomes ionized and conducts under the action of a high electric field. Since copper terminal block is a critical conductive node inside the system, any deterioration of insulation conditions may trigger partial discharge or even flashover events.

Surface contaminants such as dust and oil on the copper distribution block surface can form conductive paths under the influence of humidity, which can reduce the air withstand voltage between adjacent terminals and easily lead to local ionization at the point of electric field distortion. Changes in the dielectric constant of the insulation material after it becomes damp also alter the conduction path, concentrating the electric field in weak areas and thus promoting flashover.

Installation process errors leading to insufficient gaps between the copper terminal strip terminals or oxidation of the terminal contact surfaces can cause the electric field to be enhanced in tiny gaps. According to the principle of arc discharge, when the electric field exceeds the air breakdown strength, an arc can be generated between the terminal blocks. This arc discharge is not only accompanied by high temperatures but can also cause further insulation damage.