Termorio-S.Jose double circuit transmission line crossing several pipelines-modelling problems

This article reports the procedures used to determine the voltage applied upon several pipelines crossing the 138 kV double circuit Termorio-S.Jose transmission line. During a fault to ground, the current flowing along one of the circuits can differ, in terms of value and direction from the current flowing in the other circuit. This fact gives rise to the need of special simulation techniques which are dealt with here. This article also presents a summary of the basic calculation procedures used to determine the voltage difference which appears across the pipeline insulation (between metal and ground), when a fault occurs on the transmission line crossed by the pipeline. This voltage difference should not exceed 5 kV for safety reasons.