Arrangement for AC-voltage limiting of cathodically protected tubular lines which carry high voltage

摘要

Unacceptably high long-term influences on the tubular line occur only in limited times during high electrical loads on a high-voltage overhead line. A thyristor power section (1) is switched on by a control section (2), which contains a threshold-value switch (20...24), when the influencing voltage on the tubular line (A) exceeds a preset threshold value. The power section contains a bridge rectifier (10) and a forwards-conducting power thyristor (11). A diode arrangement (14) is arranged in a forwards-conducting manner, as a series component, in the bridge path between earth (B) and the positive output (12) of the bridge rectifier (10). The control section (1) contains a threshold-value switch (5, 55) which has hysteresis and influences the triggering voltage of the control thyristor. <IMAGE>