Study on Insulation Condition of <SF_6> Gas Insulated Cubicle (GIC)

点击翻译按钮获取中文摘要

<SF_6> gas is being used in gas-insulated substations (GIS) at pressures of a few atmosphere. Since the regular pressure of GIS is high (a few atmospheres), rather expensive pressure vessels are required, and this fact prevents <SF_6> gas insulation from being widely used for insulation at low rated voltages. The advent of gasinsulated cubicle (GIC) has made it possible to widen application of <SF_6> gas insulation to low rated voltage area. The purpose of the present study is to make clear the insulation condition of GIC with which <SF_6> and air gas mixtures may be used at near-atmospheric pressures. The results obtained may be summarized as below.1) The effective ionization coefficient, which is the most important fundamental parameter for prediction and simulation of breakdown in gases, of <SF_6> and air has been measured for E/p up to 2,000 V <cm^(-1)> <Torr^(-1)> and summarized in a form of experimental formula.2) The breakdown voltage of <SF_6> and air mixtures in uniform fields has been measured to show that the voltage assume maximum values at an <SF_6> percentage pressure of about 90%.3) Interpreting comprehensively the results obtained in the present study, use of about 80 to 100% percentage <SF_6> pressure may be recommended for use for GIC.