Prevention of stray current during welding and hot work operation for oil and gas pipeline

Large current occurs during the welding and hot work operation for oil and gas pipelines. Improper protection or wrong operation may cause fire and explosion accidents. The theoretical model was established for stray current distribution of pipeline during welding and hot work operation. The pipeline was meshed to N elements, the N-order tri-diagonal equations for each node was set up by utilizing nodal voltage method, with the catch-up method calculating the pipe-ground voltage distribution and stray current values in pipe. The convergences with respect to different spatial calculating steps were verified. With the model, the main factors affecting the stray current during welding and hot work operation were investigated, including the installation position of insulation blind plate, ground-pipe resistance, contact resistance of main welding circuit, ground protection settings of pipe and locations of connected containers. The corresponding prevention measures were brought to provide an instruction to the prevention of stray current during welding and hot work operation oil and gas pipelines.