Analysis of the Monitoring Data of UHVDC Grounding Current Interference in a Buried Pipeline

Abstract

The transmission power and rated current of the ±800 kV ultrahigh-voltage direct current (UHVDC) project is so high that the grounding current aggravate the corrosion of buried pipelines during the monopole operation period, which is a critical issue that needs to be studied. The stray current and the pipe-soil potentials (PSPs) synchronous monitors have been installed on a buried pipeline near the receiving end of the Zhalute-Qingzhou ±800 kV UHVDC transmission project and the monitoring experiment for the effect of the grounding current of the receiving ground electrode is carried out. The monitoring data of stray current and PSP offset in relation to the grounding current of the ground electrode are obtained for the first time all over the world, during the UHVDC project commissioning in October 10th and December 24th, 2017. The results of data analysis show that the pipeline 150 km away from the ground electrode is also affected by the UHVDC project, its PSP offset exceed the limit value required by the national standard for discharge measures and the dc stray current is produced in the pipeline. According to the data and calculation, the characteristics and rules of the influence of UHVDC grounding current on pipelines are acquired.