The first truly commercial underground HVDC cable manufactured
by Le Societ´e des Cˇables de Lyon was installed in
the early 1900s. This project was built for the transmission of
power between the power station at Moutiers and the railway
station in the city of Lyon. The 4-km-long cable system, used
in conjunction with the overhead HVDC transmission lines,
had a cable thickness of 18 mm mass impregnated paper
(MI). The DC operating voltage and power for the cables
were 125 kV and 30 MW, respectively [26], [27]. Since then,
the mass impregnated paper insulation has become one of the
most reliable and longest living dielectric material for HVDC
cables.