Gas-filled surge arresters operate on the gas-physical principle of the highly effective arc discharge. Electrically, surge arresters act as voltage-dependent switches. As soon as the voltage applied to the arrester exceeds the spark-over voltage, an arc is formed in the hermetically sealed discharge region within nanoseconds. The high surge current handling capability and the arc voltage, which is almost independent of the current, short-circuit the overvoltage. When the discharge has died down, the arrester extinguishes and the internal resistance immediately returns to values of several 100 MΩ.
The surge arrester thus meets almost perfectly all requirements made on a protective element. It reliably limits the overvoltage to permissible values, and– under normal operating conditions – the high insulation resistance and the low capacitance contribute to the fact that an arrester.
Post time: Jul-06-2020