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<p>This paper describes the electric field behavior of air breakdown under various electrode configurations and gap length. By using COMSOL Multiphysics, a Finite Element Method (FEM) software, the values of maximum electric field can be determined based on the air breakdown voltage data obtained from the experiment under AC stress. The results show that R0.5-plane configuration provides a very high electric field upon breakdown, compared to R6-plane, R48-plane and plane-plane configurations. In addition, the comparison between the analytical and simulation results of maximum electrical field gives almost identical results for each electrode configuration except for R6-plane.</p>

This paper discusses a new test vessel developed to investigate the breakdown test performance of gas insulation. The test vessel is equipped with certain specialty including pressure chamber and control measures. Through help from a steering, it is provide of controlling the gap length of the electrodes without the need of removing the gas. Other control measures include humidity, temperature, and pressure readings. The humidity and temperature are read wirelessly and from the readings, the necessary atmospheric corrections can be made according to standards. The developed vessel is then tested with AC breakdown test using air with various gap lengths and various electrode configurations. There are two types of electrode configuration used in this project i.e., rod (R0.5)-plane and plane-plane.

Sulphur hexafluoride (SF6) gas owns remarkable properties as insulation medium and current interrupter, which make it being widely used in gas-insulated equipment up to now. However, SF6 gas has a drawback that gives adverse effect to the environment since it is a strong greenhouse gas. As the effort to minimize the SF6 usage, this study was conducted to investigate the AC breakdown behavior of SF6/N2 gas mixtures with 10/90 ratio at low pressure levels (i.e. 0.11 MPa to 0.15 MPa) under non-uniform field (i.e. R0.5-plane and R6-plane electrodes configurations). The results of the study indicate that the breakdown voltage of SF6/N2 gas mixtures in non-uniform field increases linearly with the increase of gas pressure and electrodes gap distance. As a function of gap distance, a higher increasing rate of breakdown voltage values were achieved at lowest pressure of 0.11 MPa compared to other pressure levels. In addition, it is also found that a higher breakdown voltage values was obtained under R6-plane configuration. But, the difference in breakdown voltage values between R0.5-plane and R6-plane configuration is less significant as the gap distance is increased. It is also observed that the field efficiency factor of R6-plane is higher than R0.5-plane which indicates a more uniform field exists between the electrodes.

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