High voltage breakdown is an exciting way to destroy expensive new systems in spectacular fashion. This unfortunately happens far too often as programs usually move forward at risk as historically investigative work of this nature costs too much and takes too much time. ElectroMagnetic Consultants now has the capacity to do investigative research in record time, at a faction of the typical cost. Let's walk through the following example of our capabilities, which took less than 24 hours to go from scratch to getting results confirming the design.

The above is a 10KV bushing typically used to feed high voltage lines through some type of physical disconnect. In this case, the pink is modeled as a simple rubber compound with an epsilon value of 3. Custom dielectric dispersion tables can be used if the values are known for a given insulator. Thermal conductivities, diffusivity, and expansion coefficients can be used to investigate how the material behaves during long periods of loading. The 10KV bussbar and the square disconnect plate are all modeled as annealed copper.

Resulting equipotential voltage distribution on the bussbar can be viewed in 3D as shown above, but further inspection needs to be done by slicing the end result to look at the field levels within the dielectric insulator.

Ahh that's better. As we can see, the low dielectric value has little effect on the electrostatic potential, and is influenced more by the conductive nuts on the end of the bussbar, as well as the disconnect plate in the middle, which is being held at 0V for a reference.

No one cares about the previous two graphs. What is really of interest here is the E-Field distributions throughout the model. Ensuring that these values are within safe levels is what will eliminate breakdown and destruction of the system. Here we can see that the maximum electric field strength is no more than 0.62MV/m, which is almost an order of magnitude below breakdown.

Viewing the fields as vectors is a helpful way to diagnose issues. Simulation is a wonderful way to give a good approximation of what to expect in the real world. The field strength at which breakdown occurs depends on the respective geometries of the dielectric (insulator) and the electrodes with which the electric field is applied, as well as the rate of increase at which the electric field is applied. Because dielectric materials usually contain minute defects, the practical dielectric strength will be a fraction of the intrinsic dielectric strength of an ideal, defect-free, material. While simulation cannot account for real world challenges such as these, it does help clients design with a margin of error to take these factors into account.