Research of the Safe Distence between Gaoqing HVDC Ground Electrode and Buried Pipelines

In order to ascertain the safe distance between Gaoqing ground electrode of ±800kV Zhalute-Qingzhou HVDC project and the buried pipelines while the HVDC was operate in single-pole mode, a method for the safe distance evaluation is first presented based on equivalent circuit model of pipeline. The stray current and the pipe-soil potentials (PSP) due to ground return current is calculated given different distance between the ground electrode and pipelines. The result shows that the minimum safe distance between Gaoqing toroidal ground electrode and the pipeline is 100km, if not it is necessary to take drainage measures on pipelines.