Envelope-Based Worst-Case Analysis of Shielded Cable Systems Under Bulk Current Injection

Abstract

Bulk current injection (BCI) is a standardized immunity test method for automotive subsystems connected via electrical cables and harnesses. While BCI tests are performed using fixed configurations, real vehicle installations exhibit significant variations in cable length and grounding conditions. Since BCI-induced disturbances are strongly influenced by resonance effects, worst-case susceptibility scenarios may remain undetected. This paper presents an envelope-based evaluation of BCI-induced disturbances in shielded cable systems. Using a previously validated transmission-line-based model, worst-case distur-bance voltage envelopes are derived for variations of cable length and grounding configurations. The results show that cable length variation is the dominant factor governing resonance shifts and worst-case disturbance levels, while grounding conditions further influence the susceptibility behavior. For a fixed cable length, the current probe positions specified in ISO 11452-4 provide good resonance coverage. Representative measurements are included to validate the model for critical grounding configurations.