The Transmission Line for the SPIDER Experiment: From design to installation

•In SPIDER a −100kVdc Transmission Line (TL) carries power and signal conductors.•An original air insulated design of the TL has been conceived.•The paper reports on the construction solutions developed by the Manufacturer.•The factory type tests to validate the TL design are described.•On-site installation and final acceptance tests concluded in June 2016 are reported. SPIDER (Source for the Production of Ions of Deuterium Extracted from RF plasma) is the full scale prototype of the Ion Source for the ITER 1MeV Heating Neutral Beam Injector (HNB) and is presently under construction in the Neutral Beam Test Facility at Consorzio RFX premises, in Padua, Italy. The required Ion Source and Extraction Power Supply (ISEPS) system and the associated diagnostics need to be hosted inside a −100kVdc air-insulated Faraday cage, called High Voltage Deck (HVD); a High Voltage Transmission Line (TL) carries many power and signal conductors from the ISEPS to the Ion Source. An air insulated design of the TL, coping with the large dimensions required to host ISEPS diagnostic and power cables and duly screened against Electromagnetic Interferences (EMI), has been conceived. The paper reports on the construction solutions developed by the Manufacturer to meet the design indications and requirements of the technical specification for such unconventional device. Moreover, the factory type tests to validate the design and release the manufacturing of the overall TL are described. Finally, the paper reports on the on-site installation and commissioning activities for the final acceptance concluded in June 2016.