2. General

2.1 Historical overview

• The Leyden bottle (1745) was the first electrical energy storage capacitor. It was used in numerous physics experiments in the 18th and 19th centuries.

  • Capacitors were only used industrially to improve power factor around 1920. These devices, installed on networks, are single-tank units with a reactive power of around 500 to 1,000 kvar. Their dielectric consists of sheets of paper impregnated with mineral oil.

  • In France, this technique continued until the early 1950s. At that time, single-tank units were replaced by single-phase capacitor banks using all-paper technology impregnated with mineral oil. The electric field is 12 V/µm,...