Discussion Forum

I am struggling with a simulation of the AC/DC module, where I would like to simulate for example 4 busbars/wires/cables of 2000mm2 areas, the input is High Current(100kA). And I would like to consider the forces between them wires.

I use Magnetic Field in 2D with a Stationary or Frequency(50Hz) domain. In the Magnetic Field settings, I used the "coil" to set up the current, which in my case is a boundary condition. Next, I marked "Single conductor" and I set the value of the current. The first step was to see how does it look like for DC, so the current density is constant in the cross-section and in the result the Magnetic Field was exported. I could say that the results are good and are compared with other researches papers.

But the problem is coming when I want to apply for AC. I have changed for the frequency domain and run the simulation. I noticed the skin effect(good) and different Magnetic Field distribution around(bc of the current density), but surprisingly when I was measuring the current by "Surface Integrator: I have received MORE than I applied. I checked many times, applying few "coils" in MF and only one, and always I receive bigger current. Do I use wrong physics? Could you help me with it? On one tutorial of Comsol, I have seen that they used "Homogenized multi-turn" but later they set up as one coil. I do always compare the result with well-described phenomena, but for AC busbars I could not find papers or Magnetic field distribution calculations.

Thanks in advance :)