Abstract
The integrity of the electrical insulation is of greatest importance in the reliability of high voltage equipment. For the development of high temperature superconductivity power equipments the cryogenic insulation technology need to be established. The present research work aimed to develop practical and reliable methods that can diagnose the degradation status of the electrical insulation. In the present work an analysis has been made to study the dielectric strengths of composite laminates for designing a good insulation system. The breakdown voltages of glass fiber reinforced plastic composite laminates, natural fiber composite laminates (coir, human hair, sisal, and banana) at room temperature (300 K) and liquid nitrogen temperature (77 K) has been examined. The experimental results show that the breakdown strength at room temperature for human hair, coir, sisal and banana were found to be 134.5 kV/cm, 52.92 kV/cm, 22.93 kV/cm, 20.31 kV/cm and 18.16 kV/cm respectively while the breakdown strength at cryogenic temperature for glass fiber reinforced plastic, human hair, coir, sisal and banana were found to be 177.86 kV/cm, 118.99 kV/cm, 120.84 kV/cm, 127.67 kV/cm and 102.29 kV/cm respectively. The results suggest that there exist a significant increase in the breakdown voltage at cryogenic temperatures. From the experimental results, it is concluded that dielectrics made of natural fiber composites can be considered as an insulation medium for cryogenic applications.