Optimized Charge Simulation Models of Horizontal Sphere Gaps

The horizontal sphere gap is modeled using six point charges per electrode as a test case. Two intuitively felt optimized charge simulation method (OCSM) models of horizontal sphere gap arrangement are set up by selectively changing degree of freedom to understand its effect on the simulation errors. The optimal location of charges is obtained using genetic algorithm (GA). A large number of numerical experiments are conducted by varying potential assigned to the low potential sphere, height of the spheres above the ground plane and gap separation. Lower potential sphere always shows higher error. For a typical case, the maximum surface potential error with increased freedom in locating charges reduced to 4% from its earlier value of 9.5%. The simulations with symmetrical supply show maximum surface potential error of 1.0% on both the spheres. On the other hand simulating a ground potential electrode near a high voltage electrode involves more errors and hence more effort. The charge simulation method being semi analytical technique, the shape of the geometry and symmetry (if any) plays a major role and setting up accurate OCSM model still requires user experience.