long rod suspension composite insulator

The ambient air temperatures is no higher than +40º C, no lower than -40.
The altitude above sea level does not exceed 1000-2000m
AC system frequency 50Hz or 60Hz
Industrial frequency voltage brough to bear on arrester for a long time does not exceed arrester's sustained operation voltage.
Maximum wind speed does not exceed 35m/s
The earthquake intensity does not exceed 7 degrees.
The filthy area should be given clear indication.
Keystone:
The zinc oxide arrester is the most advanced over-voltage protector in the world. Due to make the resistor disc of core component mainly adopt zine oxide arrester. Compared with the conventional silicon carbide arrrester, this presciption of the product improves greatly the volt-Amperecharacterisics of the resistor disc and increased through-current capability at over-voltage so as to bring a radical changes for the characteristics of the arresters.

Under the circumstance of normal operating voltage, the current through the arrester is just on mincroampere degree. When suffered from the current through the arrester increase to several thousand amperse, while the arrester will be under the circulating state and release over-voltage energry so as to protecting the power thansmission equipments against the damage caused by the over-voltage.