Dependence of Charge Behavior on Electric Field Distribution around GIS Spacer under HVDC Application and Polarity Reversal

Under HVDC application, we have to consider the charge behaviour on the GIS solid spacer for accurate numerical computation of DC electric field. In addition, when DC polarity reversal as the operation of the DC power transmission system is done, the accumulated charge may strongly distort the electric field distribution in the transient state. In DC field analysis, the conductivity of every dielectric material in the insulation system becomes important factor as well as its dielectric permittivity. However, the conductivity of gaseous dielectrics is not easily determined. This is because the conduction current would be less dependent of electric field strength in the practical field level when the only natural ionization of gas molecules plays a role as a source of conduction current. In…