The possibility of using glycerin as the dielectric in pulse forming lines

In this paper, an approximately scaled coaxial test device is designed and constructed to study the breakdown characteristics of glycerin dielectric in pulse forming lines (PFLs). In the test device, factors affecting the breakdown strength of the glycerin are investigated, including polarity of high voltage, applied gas pressure, temperature, magnetic field, and the electrode surface characteristics. The time and temperature characteristics of the glycerin resistivity are investigated as well. The results show that glycerin has extremely high and stable resistivity, and its breakdown field strength is independent of the polarity of the applied electric field. As the nitrogen gas pressure is applied up to 2 MPa on the glycerin, the breakdown field strength is increased by 40%. When the temperature is changed from 10 to 55 °C, the breakdown field strength reduces from 310 to 165 kV/cm. It is also found that there is no effect on the breakdown field strength of glycerin on magnetic field under 1T. Moreover, the filling process of the glycerin PFL is investigated for exhausting the gas as far as possible. The glycerin PFL has been employed in pulsed power generators, and some breakdown problems in the practical application have been solved.