Resistance to Tracking of EPDM Aged by Gamma Irradiation under AC and DC Voltages

The present paper reports the results of a study of dielectric ageing of Ethylene Propylene Diene Monomer (EPDM) by gamma radiation. EPDM flat specimens were aged under gamma radiation with three different doses. Samples were irradiated in air up to 300 kRad with a dose rate of 51 kRad/h using a 60Co gamma source. The resistance to tracking on applying DC and AC voltage was examined. We found that the DC resistance to tracking is lower than the AC resistance. The tracking resistance under –ve DC voltages are lower than +ve DC values. With the increase in radiation dose, the DC and AC tracking resistances change in a non-linear way. The erosion depth and contact angle affected by radiation have been studied. In addition, Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) analyses were done, to analyze the morphological changes.

[1]  R. S. Gorur,et al.  Contamination performance of polymeric insulating materials used for outdoor insulation applications , 1989 .

[2]  Marc Tavlet,et al.  Observation of radiation degradation of electrical insulators in the CERN particle accelerators , 1999 .

[3]  B. X. Du,et al.  Discharge energy and dc tracking resistance of organic insulating materials , 2001 .

[4]  S. Kobayashi,et al.  Environmental factors affecting DC resistance to tracking of polyethylene , 2003, IEEE Transactions on Dielectrics and Electrical Insulation.

[5]  E. Cherney,et al.  Non-Ceramic Insulators for Contaminated Environments , 1981, IEEE Transactions on Power Apparatus and Systems.

[6]  I. Kuriyama,et al.  Radiation Resistance of Cable Insulating Materials for Nuclear Power Generating Stations , 1978, IEEE Transactions on Electrical Insulation.

[7]  R. Sundararajan,et al.  In-service aging and degradation of 345 kV EPDM transmission line insulators in a coastal environment , 2004, IEEE Transactions on Dielectrics and Electrical Insulation.

[8]  J. Mackevich,et al.  Polymer outdoor insulating materials. II. Material considerations , 1997 .

[9]  Robert B. Blodgett,et al.  Insulations and Jackets for Control and Power Cables in Thermal Reactor Nuclear Generating Stations , 1969 .

[10]  Shaobin Li,et al.  Effect of gamma-ray irradiation on the TSC in polyethersulfone , 1997 .

[11]  Shigeo Kobayashi,et al.  Effects of Sample Temperatures on Tracking Resistance of Organic Insulating Materials , 1996 .