Investigation of Surface Degradation of Aged High Temperature Vulcanized (HTV) Silicone Rubber Insulators

Abstract

Polymeric composite insulators are subjected to varying work conditions like rain and heat, which create an impact on degradation during their long service period. Electrical tracking under the Alternating Current (AC) field plays a predominant role in surface degradation, which can be different for fresh and aged insulations. The tracking studies on the fresh and aged polymeric insulation therefore become significant. Motivated by this, an indigenous low-cost electrical tracking setup was developed, and the tracking studies were carried out as per International Electro technical Commission standard (IEC) 60587 on fresh, thermal-aged and water-aged silicone rubber samples. Contact angles of samples were measured to analyse the effect of ageing on hydrophobicity. Further, to analyse the influence of ageing on insulation integrity, tracking tests were conducted and parameters like leakage current pattern and magnitudes, tracking length and loss of weight in the material due to tracking were examined. The physicochemical impacts of ageing on the surface degradation of the samples were also analysed using X-ray diffraction analysis and Fourier Transform Infrared Spectroscopy analysis. The investigations added insight into the degradation mechanism of polymeric insulators in terms of their electrical performance and physicochemical changes in the material. Comparison of these changes showed that ageing could influence surface degradation of samples.

Evaluation of the Impact of Organic Fillers on Selected Properties of Organosilicon Polymer

“…For the unmodified material, stress at break increased after aging for 7 days (1.90 MPa, a 45% increase compared to the native sample) and slightly dropped to 1.48 MPa (13% increase) after 28 days. This could be caused by increased crystallinity of the polymer after aging [ 33 ]. Only in the case of GCW composites, for 10% and 20% filler fractions, stress increased with aging days (8% and 16% after 7 days and 2% and 7% after 28 days compared to the native samples).…”

Electrical Strength of Natural Esters Doped by Iron Nanopowder in a Hydrophobic Carbon Shell

“…Additionally, the lifetime of such material decreases drastically. As shown in [21], the reduction of hydrophobicity of insulators results in their faster degradation. Water contained in the esters is generally present in the dissolved and undissolved form.…”

Effect of Ageing on the Tracking Characteristics of High-Temperature Vulcanized Silicone Rubber Hybrid Composites for High Voltage Insulation

“…The temperature accuracy of the hot air oven is ±2 • C. Thermal stress was maintained at a high temperature of 150 • C for a cumulative period of 240 h. Similarly, for water ageing, five samples were immersed in 500 mL of demineralised water for 500 h. The temperature of the water was kept at room temperature at atmospheric pressure [28,29]. In our previous research, a•similar ageing methodology was adapted to study the effect of the ageing on Miro ATH filled Silicone rubber insulators [37].…”

“…The primary voltage of 204 V is set to get 4.5 kV at the secondary side of the test transformer. The design of this low-cost indigenous tracking setup was reported in our previous tracking studies on micro ATH filled silicone rubber insulation [37].…”