Pliability Assay of Conventional Gas Insulated Transmission Line and Flexible Gas Insulated Transmission Line Regarding Horizontal Directional Drilling Based Underground Cable Laying for Metropolitan Areas

Gas insulated transmission lines (GIL) have been in use as an efficacious alternate of underground cables and overhead transmission lines. Conventional metal enclosed gas insulated line encounters several technical dilemmas like laying difficulties and jointing complexities due to structural rigidity along with environmental constraints due to possible SF6 gas leakage in case of a seismic event. In this research paper a flexible GIL model is developed and compared with a conventional GIL model regarding enclosure and conductor flexibility. Simulation results reveal that the proposed scheme could result in substantial reduction in minimum bending radius and the required surface area for cable laying. In addition, flexibility will facilitate the horizontal directional drilling based cable laying procedure. Further, the proposed scheme could also eliminate the requirement of acceleration dampers, corrosion protection techniques and trench development as compared to the conventional GIL scheme which could be highly beneficial for implementing underground high voltage transmission lines in metropolitan areas.