The insulator with built-in surge arrester unit

which combines the functions of insulator and line arrester with series-gap

can provide support and insulation for fixed-line

and restrain lightning over-voltage and power-frequency continuous current arc. Explosion protection performance is an extremely important issue in its design

and experimental study is necessary. In this study

two kinds of representative insulators were selected to conduct experimental research on their explosion protection performances through short-circuit current tests. The internal short circuit discharge energy of both kinds of insulators was obtained under the actions of the electric power and the thermal stress of power-frequency continuous current arc. The results show that the explosion protection performance of the composite insulators with built-in surge arrester unit is better than that of the porcelain insulators with built-in surge arrester unit. Small current short circuit test verifies that the explosion protection performances of both kinds of insulators meet the application requirement. According to the actual operating conditions of the arresters in distribution system

the explosion protection performance assessment of the insulators can take the single-phase grounded short-circuit fault condition into account.