Title :
Electric field modeling and field formation mechanism in HVDC SF6 gas insulated systems
Author_Institution :
Transmission & Substations Div., Israel Electr. Corp. Ltd., Haifa, Israel
fDate :
4/1/2003 12:00:00 AM
Abstract :
This paper reports on the electric field behavior in HVDC SF6 gas insulated systems. In the field model definitions, the SF6/epoxy interfaces are assumed as thin slightly conducting layers with non-zero thickness. The boundary conditions involving surface-reduced parameters of these layers are adopted. This allows avoidance of problems of calculation regarding the proximity of interfaces between subdomains. The boundary-value problem describing capacitive-resistive time-varying electric field is formulated. On this basis, the transient HVDC electric field model and time domain-calculating algorithm are constructed. The model accounts simultaneously for both the surface layer properties and bulk conduction parameters of the bounding dielectrics, while surface conductivity may be specified as a non-linear or an arbitrary function. The method employs direct integration of a continuity equation in the time domain with the calculation of an electrostatic field approximation at each integration step. The basic features and applicability of the method are discussed. The model has been applied for analysis of HVDC electric field formation mechanism in SF6/epoxy insulation. It is demonstrated that charge accumulation phenomena cannot be described by a single time-stable mechanism. Some directions regarding further development of the field model and calculating algorithm are suggested.
Keywords :
HVDC power transmission; SF6 insulation; boundary-value problems; electric breakdown; electric fields; epoxy insulation; gas insulated switchgear; HVDC SF6 gas insulated systems; SF6; SF6/epoxy interfaces; boundary conditions; boundary-value problem; capacitive-resistive time-varying electric field; charge accumulation phenomena; electric field behavior; surface-reduced parameters; thin slightly conducting layers; time domain continuity equation; time domain-calculating algorithm; time-stable mechanism; Boundary conditions; Conductivity; Dielectric breakdown; Dielectrics and electrical insulation; Electrostatics; Gas insulation; Geographic Information Systems; HVDC transmission; Surface cleaning; Voltage;
Journal_Title :
Dielectrics and Electrical Insulation, IEEE Transactions on
DOI :
10.1109/TDEI.2003.1194101