Investigation of the factors governing water absorption in HV composite insulation

The sensitivity of HV composites to water absorption is studied for various materials and conditions. The role of ions in the transportation of water into composite insulation is investigated. The dependence of water uptake on the applied electric field, the nature of the ions and their concentration are reported. The effect of the frequency of the applied field on water ingress is presented for a range of frequencies from 5 to 15 kHz. The strength of adhesion shown by various reinforcing materials to the surrounding resin is chosen to demonstrate the effect of these materials on water absorption. An investigation of the role of temperature in water uptake is also described.