Surge arrestor circuit for power distribution system - has LC filter and earthed capacitor shunted by varistor

摘要

The surge arrester circuit, for power distribution systems, is equally effective with AC as with DC voltages and consists of an LC input filter with the inductor between input and output and the capacitor earthed. A spark extinguishing circuit is connected after the filter and consists of a relatively large earthed capacitor (3) and a non-linear resistance (7) in series with it. The non-linear resistance is formed by a varistor. The extinguishing circuit (capacitor + varistor) has an impedance roughly equal to the supply network at the supply frequency.