Title :
Dynamic behaviors of the streamer development and propagation in SF6
Author :
Zheng, Dianchun ; Zhu, Shihua ; Zhang, Zhonglin ; Lv, Shuming
Author_Institution :
Key Lab. of Eng. Dielectr. & Its Applic., Harbin Univ. of Sci. & Technol., Harbin, China
Abstract :
SF6 gas is an important insulated medium and is wildly used in electric power industry for gas-insulated equipment; this paper aims to deeply understand the streamer discharge mechanism in SF6, and to better use of SF6 gas in the electrical equipment. The two dimensional and self-consistent fluid model of the gas discharge is established based on the electron and ions continuity transfer equations coupled to Poisson´s equation, furthermore including the model of photoionization. To overcome the problem about enormous calculation required of photoionization, some simplified methods are implemented in this paper. In simulation, the particle flux-continuity equations is solved by the flux corrected transport technique (FCT), and the iterative symmetric successive over-relaxation (SOR) method is used to solve the coupling Poisson´s equation. Results of two-dimensional simulation of cylindrically symmetric streamer in SF6 between parallel-plane electrodes are obtained. We present and discuss conclusions about streamer transport based on the results of these studies. The temporal and spatial transformation of charged particle densities, electric field strength, discharge current and discharge propagation velocity during the progression of discharges are investigated and the results indicated that, the processes of discharge have three phases: avalanche phase, streamer formation phase and streamer propagation phase. In addition, by comparing the results of simulation with and without photoionization process can be seen that the photoionization offers a large number second electron, and is absolutely necessary during the streamer propagation phase, which accelerates the velocity of the streamer propagation.
Keywords :
Poisson equation; SF6 insulation; discharges (electric); electric fields; electricity supply industry; electrodes; electron transport theory; gas insulated switchgear; iterative methods; photoionisation; plasma simulation; plasma transport processes; SF6 gas; SOR method; avalanche phase; charged particle density; coupling Poisson equation; cylindrically symmetric streamer; discharge current; discharge propagation velocity; electric field strength; electric power industry; electrical equipment; electron transfer equation; flux corrected transport technique; gas discharge; gas-insulated equipment; insulated medium; ionization model; ions continuity transfer equation; iterative symmetric successive over-relaxation method; parallel-plane electrodes; particle flux-continuity equation; self-consistent fluid model; spatial transformation; streamer development; streamer discharge mechanism; streamer formation phase; streamer propagation; streamer transport; temporal transformation; two-dimensional fluid model; Anodes; Discharges; Electric fields; Ionization; Mathematical model; Sulfur hexafluoride;
Conference_Titel :
Electric Power Equipment - Switching Technology (ICEPE-ST), 2011 1st International Conference on
Conference_Location :
Xi´an
Print_ISBN :
978-1-4577-1273-9
DOI :
10.1109/ICEPE-ST.2011.6123041