Influence of HVDC Transmission System Ground Electrod on West-East Gas Pipeline

This study is targeted to investigate the electrical interference of monopolar ground return operation of high-voltage direct current (HVDC) ground electrode in Wengyuan on West-East Phase Ⅱ gas transmission pipelines.The relationship between the injection current from HVDC ground electrode and the interference potentials on the pipeline was comprehensively analyzed.The results show that at the injection current of 1 200 A,the interference potential on the pipeline reached up to 100 V,and the interference potential shifts were towards opposite direction at the far end (section distant from the ground electrode) and the near end (section close to the ground electrode) of the pipeline,with higher interference severity at the near end than at the far end.The mitigation measures of directly bonding the station and valve chamber grounding system with the pipeline was capable of effectively decreasing the pipeline potential shift at the bonding locations so as to reduce the risk,but meanwhile,increasing the stray current in the pipe at other locations with the interference severity deteriorated accordingly.Therefore,if the station grounding systems are to be used for HVDC interference mitigation,it is strongly recommended that bond sites be properly selected and effectively optimized.