Analysis of Induced Potential on Gas/Water Pipelines due to Extra High Voltage AC/DC OHTL

Abstract

The growth of world population and the need to transport electricity more efficiently has made the integration of both alternating current extra high voltage overhead transmission lines (AC EHV OHTL) and direct current extra high voltage overhead transmission lines (DC EHV OHTL) more attractive. A common constraint in most parts of the world is the availability of land for OHTL servitudes/right-of-way passages. This constraint requires an assessment of shared servitudes for both AC and DC overhead transmission line (OHTL). Where possible shared structures should also be considered which may be located in areas where metallic pipes exist such as, water and gas pipelines. When gas and water pipelines are laid in parallel with extra high voltage overhead transmission lines (EHV OHTL), a potential will induce on the pipeline due to the electromagnetic coupling (EMC) impact and can reach dangerous levels, resulting in potentially unsafe conditions for utility operating personnel and in those areas accessible to the public at large. Such induced potential can exasperate pipeline corrosion and cause undesirable electromagnetic interference on neighboring communication networks. In this paper, a pipeline located close to an extra high voltage overhead transmission lines (AC/ DC EHV OHTL) is studied. The induced potential on pipeline is analysed and studied in two scenarios: AC OHTL and DC OHTL. The study analyses the induced potential on pipeline and the impacts of each system individually. In addition, the impact of pipeline location profiles and earth soil resistivity are discussed. The analysis is carried out by using Alternative Transient Program which is the modelling package of Electromagnetic Transient Program Software (ATP/EMTP).