Electrodynamic Force Calculation on Bus Bars using Maxwell
Introduction
In this session, we will conduct a three-phase short circuit analysis using Simplorer. Our objective is to simulate a power transformer and perform busbar force calculations.
Setup and Configuration
- Define Voltage Sources:
- Set three voltage sources in sine wave mode.
- Specify voltages, frequencies, and phase shifts.
- Set System Parameters:
- Configure resistances and inductances to represent a simplified power transformer.
Busbar Force Calculation
- Current Selection:
- Select values at 10 milliseconds.
- Simplify currents to 20 kiloamps for the two high side busbars and -40 kiloamps for the remaining busbar.
- Magneto-static Analysis:
- Utilize three copper busbars.
- Apply boundary conditions and define a balloon boundary.
- Excitation Definition:
- Apply three-phase current excitation.
- Positive current in two busbars and negative current in one, with the latter carrying twice the current in the opposite direction.
- Force Parameter Definition:
- Apply force parameters individually to each busbar to avoid calculating the total system force.
Mesh and Solution
- Mesh Operation:
- Select the vacuum region and busbars.
- Refine the mesh using a length-based inside mesh.
- Solution and Analysis:
- Add a solution and run the analysis, which will solve quickly.
Results and Visualization
- Magnetic Flux Density Plot:
- Plot the magnetic flux density and refine by adding more divisions and setting quality to very fine.
- Observe that flux density is concentrated near the busbar carrying the most current.
- Flux Density Vector Plot:
- Select the vacuum region for plotting, not the copper, to visualize flux lines in the vacuum.
- Force Results:
- Access results under "Results Solution Data".
- Force is applied mostly in the x-axis, with individual forces on busbars as follows:
- Busbar 1: 124 N
- Busbar 2: 1045 N
- Busbar 3: 1169.5 N
- The sum of forces is close to zero, indicating that the total force applied to the system is balanced.
Conclusion
Thank you for following along with this analysis of electrodynamic forces on busbars using Maxwell. The results demonstrate the effectiveness of our setup and analysis approach.
We will start our three-phase short circuit analysis using Simplorer. We will define three voltage sources in sine wave mode, setting their voltages, frequencies, and phase shifts.
We will also set the resistances and inductances of the system, representing a power transformer in a simplified way, to perform busbar forces.
Currents are high, so we will select the values at 10 milliseconds and simplify them to 20 kiloamps for the two high side busbars and 40 kiloamps for the remaining busbar. We will perform magneto-static analysis on the busbar system.
We have three copper busbars, so we will apply our boundary condition, selecting the borders and defining a balloon boundary. Next, we will define our excitations by selecting each of the two values and each of the objects, which are the busbars.
We will apply an instant of three-phase current excitation, with positive current in two of the busbars and negative current in one of them. The last busbar will carry twice the current of the other busbars but in the opposite direction.
Now, we will define a force parameter, ensuring not to select all the busbars, which would give us the total force of the system. Instead, we will apply the force parameter to each of the busbars individually.
Next, we will select the vacuum region and the busbars to define a mesh operation, refining the mesh with a length-based inside mesh. Finally, we will add a solution and run the analysis. This one will solve quickly.
Now we can plot the magnetic flux density, refining the plot by adding more divisions and setting the quality as very fine. The flux density is mostly concentrated near the busbar carrying the most current.
Next, we will plot the flux density vector, selecting only the vacuum region, not the actual copper. The flux lines are plotted in the vacuum, not in the copper. The flux density is concentrated near the busbar carrying the least current.
Taking a look at the force results, we can see the force based on the surface of the busbars individually. The force will be applied mostly in the x-axis. Busbar 1 has 124 N in one direction, Busbar 2 has 1045 N, and Busbar 3 has 1169.5 N.
If you sum all three, you will get a value close to zero, which makes sense because that means the total force applied to the system is zero. Thank you.
