Experimental and numerical study on formation of interface separation and interfacial dielectric strength of GIL insulator

Zihao Guo, Zehua Wu, Haoran Wang, Huidong Tian, Lilan Liu, Zongren Peng, He Li, Qing Wang

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


As the transmission capacity of gas insulated transmission line (GIL) increases, the synergistic improvement in dielectric and mechanical strengths of GIL insulators is urgently needed for the development of advanced power systems. Mechanical defects in power equipment are prone to induce discharges during high voltage operations, which need to be mitigated. In this paper, the strains on the GIL insulator surface are measured by fiber Bragg grating (FBG) strain sensors during hydrostatic tests. An abnormal change of strain is detected near the interface between center conductor and the spacer. The numerical results of stress distributions of GIL insulator during manufacturing and high-voltage operation are calculated by the finite element method. The results indicate that the mechanical stresses are concentrated at the interface, which lead to the development of conductor-spacer interface separation. In addition, based on the hydrostatic test and the FEM calculations, the dielectric interfacial strength, including the electric field distribution, and flashover are investigated by a combination of numerical and experimental studies. The results indicate that the air gaps generated by the separated interface distort the electric field at the tip of the gap, which is likely to cause discharges and reduce the gas-solid interfacial flashover strength of the insulator, placing concerns of insulation failure and even operating failures of GIL. This work sheds light on the importance of interfacial structure of power equipment and will guide the design and the manufacture of GIL insulator.

Original languageEnglish (US)
Article number8924102
Pages (from-to)1738-1746
Number of pages9
JournalIEEE Transactions on Dielectrics and Electrical Insulation
Issue number6
StatePublished - Dec 2019

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering


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