High voltage surge protection for electrical power line

摘要

A surge protection device comprising an inductor and a limiting bridge stage (10) with two oppositely biased power diodes (15,16) each connected in series with a high-valued capacitor, features an inductor connected in a first stage including a spark-gap (6) to ensure decoupling by the inductor from the second limiting bridge stage. A time-delay relay (10A) is disposed at the terminals of each power diode/capacitor combination to enable charging of the capacitors through a resistor (20) and auxiliary diodes (21, 22) connected between the relay and the power line on the one hand and between the power diode and the capacitor on the other hand, and the subsequent blocking of the bridge once the capacitors have been charged.