Electrostatic field calculation in air gaps with a transverse layer of dielectric barrier

In this paper the influence of transverse layer of dielectric barrier to the electrostatic field strength of air gaps using a hyperbolic needle-to-plane configuration is investigated. A three dimensional field problem is presented for simulating the electrostatic field in the air gap. This is achieved by using the charge simulation method. Group of ring charges are used to simulate the needle surface. A genetic algorithm is used for optimum number, location, dimension and value of simulating ring charges. The used needle tip radius was 8 μm while the gap spacing varied from 0.3 cm to 50 cm. The optimum barrier position minimizes the maximum electrostatic field and the electric energy density at the needle tip and consequently maximizes the required breakdown value. The simulation result has been compared with available experimental observations. A good agreement is found between the numerical and experimental data.