Breakdown phenomena in ultra-fast plasma closing switches

Timoshkin

Wilson

et al. 2021

Plasma

The present paper investigates the breakdown characteristics—breakdown voltage, with breakdown occurring on the rising edge of the applied HV impulses, and time to breakdown—for gases of significance that are present in the atmosphere: air, N2 and CO2. These breakdown characteristics have been obtained in a 100 µm gap between an HV needle and plane ground electrode, when stressed with sub-µs impulses of both polarities, with a rise time up to ~50 ns. The scaling relationships between the reduced breakdown field Etip/N and the product of the gas number density and inter-electrode gap, Nd, were obtained for all tested gases over a wide range of Nd values, from ~1020 m−2 to ~1025 m−2. The breakdown field-time to breakdown characteristics obtained at different gas pressures are presented as scaling relationships of Etip/N, Nd, and Ntbr for each gas, and compared with data from the literature.

Section: Breakdown Voltage and Time To Breakdown In Investigated Gasesmentioning

confidence: 99%

The Nanosecond Impulsive Breakdown Characteristics of Air, N2 and CO2 in a Sub-mm Gap

Timoshkin

Wilson

et al. 2021

Plasma

“…Yet, the blowsystem is usually large in size and expensive. Hydrogen with its high thermal diffusivity and high molecular speed allows the recovery time to be an order of magnitude faster without refer to gas blow [2][3][4] and it is widely used in Ultra Wide Band(UWB) [5][6][7]. In the references above ， the investigations of hydrogen insulating recovery characteristic is limit to low voltage or short pulse width.…”

Section: Instructionmentioning

confidence: 99%

Application of a self-breakdown hydrogen spark gap switch on high power pulse modulator

2007 16th IEEE International Pulsed Power Conference

Yin

Zhan

et al. 2007

Hydrogen has the best recovery property compared with other gases such as N2 and SF6, which has a potential application on the multi-pulse and high repetitive pulse modulator. This paper introduced a high pressure hydrogen gas switch with two cylindrical structures. The stress of the switch under high pressure is analyzed theoretically, and the pressure of hydrogen gas in the switch was hydrostatically tested up to 30atm. Such a switch was employed on high power pulse modulator with water dielectric PFL (Pulse Forming Line). At the switch breakdown voltage of 520kV and the pressure of hydrogen 12atm, a 230kV, 31kA and 60ns during time electron beam is obtained at the field-emission diode. Furthermore, when the switch was filled in different gases such as H2, N2, SF6, the rise times of diode voltage of modulator have been compared at the switch breakdown voltage 400kV. The results show that the rise times of diode voltage is reduced obviously when hydrogen is used as the dielectric of spark gap switch.

“…Grenoble, France (e-mail: ting.liu@strath.ac.uk; igor.timoshkin@strath.ac.uk; scott.macgregor@strath.ac.uk; mark.p.wilson@strath.ac.uk; m.given@strath.ac.uk; nelly.bonifaci@ g2elab.grenoble-inp.fr; rachelle.hanna@g2elab.grenoble-inp.fr) on different experimental and modelling aspects of fast, µs and sub-µs, breakdown events in gases reflects the importance of understanding of complex fundamental breakdown processes. Development of plasma closing switches, [2], [3], circuit breakers, [4], and gas-insulated systems, [4], requires comprehensive information on such gas breakdown processes. Understanding of the basic breakdown mechanisms also provides a basis for further development of environmental, bio-medical and other practical applications of gas discharges, [5].…”

Section: Introductionmentioning

confidence: 99%

Field-Time Breakdown Characteristics of Air, N₂, CO₂, and SF₆

IEEE Trans. Plasma Sci.

Timoshkin

MacGregor

et al. 2020

The dielectric performance of gases in insulation systems used in high voltage power and pulsed power applications is a subject of intensive theoretical and experimental investigation. Transient breakdown processes in gases stressed with short, high-field impulses, have been studied for many decades. However, there are still significant gaps in the understanding of the main breakdown processes and mechanisms associated with fast transient breakdown processes in gases. This knowledge is important for optimisation of gaseous insulating systems and for coordination of gaseous insulation in power and pulsed power apparatuses. This information is also required for the development of gas-filled components such as circuit breakers and plasma closing switches. The present work is aimed at analysis of the field-time breakdown characteristics of air, N 2 , CO 2 , and SF 6 , using kinetic and drift-diffusion approaches. The kinetic approach is based upon the avalanche-to-streamer transition criterion, while the fluid drift-diffusion model requires self-consistent numerical solution of the continuity equations for charged species, and the Poisson equation for the electric field. The time to breakdown as a function of the applied field was obtained for all investigated gases. The obtained analytical results agree well with the experimental data reported in the literature, which suggests that both approaches can be used for insulation coordination, and for the development of gas-insulated power and pulsed power systems and components. Index Terms-Transient breakdown in gases, ionization front, time-field breakdown characteristics.