Novel installation of a 138kV pipe-type cable system under water using horizontal directional drilling

While the power cable industry throughout the world is moving towards using extruded cable systems for most new ac cable projects, some North American utilities continue the use of high-pressure pipe-type (HPPT) cable systems for specific projects because of the long history of reliable operation using oil-impregnated paper and because the systems afford favorable conditions where long pulling lengths are required. This paper discusses the use of a unique cable design and application of horizontal directional drilling (HDD) to install nitrogen gas-filled HPPT cable under a marine setting in order to minimize the impact on the environment. The HPPT cable system permitted very long cable pulling distances of more than 1.6km, and was able to meet the utility's power transfer needs. The paper summarizes challenges that were encountered during design and construction of the project.