Modeling And Experimental Researches On The Characteristics Of Vacuum Arcs In Short-gap VCB

VCB(Vacuum circuit breakers) as controlling and protecting devices in power system,have many advantages,such as powerful extinction capability,small in size, light in weight, maintenance-free, long working-life, no pollution etc.,which have been widly applied in the power system. At present, researches on vacuum switches are important subjects of the advanced topics in the electrical switches filed. The features of vacuum arc in short gap including macro arc modes and micro characteristics of metal vapor, are very important and foundational research in the design of multi-breakers high voltage vacuum switches and intelligent phase-control switches.This paper briefly reviews the overseas and dometic developing history and the status of VCB, which summarizes the basic characteristics and former achievements of VCB. And then educe the developing significance of multi-breakers switches's application in high-voltage velel and intelligent phase-control switches is put forward. In this paper, vacuum switching arc in short gap is researched using experiments and computer simulation, the forms and inner plasma parameters are the proposed content and objectives of this studyTo describe vacuum switching arc in short-gap by experiments, vacuum arc experimental device is established, which includes a power supply circuit whose frequency of removable vacuum room used to extinguish arc are about 50Hz, and a high-speed image acquisition system based on CMOS.Using the high-speed image acquisition of the vacuum arc, we can analy morphological characteristics of vacuum switching arc in short gap. Besides, a set of high precision and high-resolution image acquisition system based on CCD is established, through which the arc of high-quality images can be obtained so that we can get experimental basis for plasma parameters within the metal vapor arc. We design a synchronous control circuit of vacuum switch arc to make the trigger circuit and arc synchronization of image acquisition work at the same time.To use optical and digital image processing technology in the diagnosis of vacuum arc.Firstly vacuum switching arc image is preprocessed by digital image processing, then the vacuum switch arc geometry is extracted and the burning process of diffusion combustion characteristics are analyzed, while the gray image distribution and its contour lines were drawn. Lastly, relative displacement and correlation of arc vacuum switch particles are diagnosed by image particle velocimetry technology and Delphi. In the paper, to describe the high-current short gap vacuum arc behavior in interrupters, a model of two-dimensional steady-state short gap vacuum arc is established based on the two-fluid model of ions and electrons and Maxwell's equations. Electromagnetic phenomena and heat transfer process are studied in the diffusion process of the arc. The influence of external electrical parameters on the arc characteristics and the characteristics of the external ports are reseached.By calculating and simulating, it also obtain the distribution of vacuum arc plasma parameters.At last, we use short gap vacuum switch arc dynamic energy analysis to study the arc phenomena after zero, and analyze the diffusion process of remained arc plasma in vacuum arc gap and control the vacuum gap of energy, optimize the local electric field distributions inside the chanmeber,to guide the design of vacuum chamber in short-gap.In this paper, vacuum switching arc macro-morphological characteristics are studied by using modern advanced optical technology, Digital image processing technology and computer simulation, which is an important part as a key project of National Natural Science Foundation of China. It can support the theoretics research and development of new generation of intelligent VCB.