Investigation of the behavior of protection elements against field radiated line coupled UWB-pulses

摘要

To protect electronic systems against electromagnetic interferences ingeneral nonlinear protection circuits are used. These protection circuitsare optimized mostly against special transient interferences such aslightning electromagnetic pulses (LEMP) or electromagnetic pulses caused bynuclear explosions (NEMP). Previous investigations have shown that theseprotection elements could be undermined by so-called ultra wideband (UWB)pulses. Thereby a direct charge of the UWB-pulse to the elements has beenassumed. This assumption was a worst case approximation because in practiceUWB-pulses only get into systems by coupling effects. In this investigationthe behavior of typical nonlinear protection elements has been tested withfield radiated line coupled UWB-pulses. For that line coupled UWB-pulseshave been defined depending on the coupling behavior of typical electronicsystems and a possibility of generation of this kind of pulses is presented.After it typical nonlinear protection elements such as spark gaps, varistorsand protection diodes have been tested with the previously defined testpulses. Finally the measured behavior of the elements has been compared withthe behavior by direct charged UWB-pulses and the protection effect of theelements against field radiated line coupled UWB-pulses is re-evaluated.