Dielectric Behavior of Compact Design Three Phase Coated Gas Insulated Busduct with Metallic Particle Contamination
The use of a gaseous medium with higher dielectric strength like sulphur hexafluoride (SF6) instead of air helps in manifold reduction in the size of the sub-station component. Compact GIS systems are essentially three-phase common systems with more than one functional element in one enclosure. Metallic particles can be either free to move in the GIS or they may be tuck either to an energized electrode or to an insulator surface. If a metallic particle crosses the gap and comes into contact with the inner electrode or if a metallic particle adheres to the inner conductor, the particle will act as a protrusion on the surface of the electrode, and the voltage required for breakdown of the GIS will also cause a significant reduction of the breakdown voltage. One method of conducting particle control and deactivation is by coating the inner surface of the outer enclosure. To determine the particle trajectories in a three-phase common enclosure gas insulated busduct (GIB) an outer enclosure of diameter 500 mm and inner conductors of diameters 64 mm spaced equilaterally are considered. Aluminum, copper and silver particles were considered to be present on enclosure surface. Simulation of particle movement with reduced phase conductor is also carried out with a view to obtain optimum size of conductor for reliable operation by reducing the original diameter of the conductor from 64 mm to 54 mm in steps of 5 mm.
Study of Electric Field Stress with Metallic Particle Adhering to FGM Spacer in Three Phase GIS
Recently, spacer design is considered as an important factor for the smooth functioning of three phase gas insulated busduct (GIB) to prevent itself from several defects like delamination, void, particle etc. In this paper, a post type spacer with functionally graded material (FGM) has been designed for a three phase GIB with particle and further electric field stress is minimized by inserting metal inserts. FGM post type spacer is spatially distributed with multiple fillers materials to achieve uniform electric field stress using the finite element method. Simulation is carried out with the designed spacer and with a particle as a defect for different FGM gradings and operating voltages. The effect particle with different sizes is minimized with the insertion of the metal insert to the post type FGM spacer and the results obtained are presented and analyzed.
Globalization and the Internationalization of Legal Education in the United States: An Annotated Bibliography
Globalization and its influence on legal education is a topic of growing interest to the legal profession and to legal educators alike. The first articles on the subject appeared in the mid-1990s, and the frequency of publications has been increasing ever since. This bibliography provides annotations to English-language law journal articles published between 1995 and 2008 that focus on the impact of globalization on legal education in the United States.