Electromagnetic forces in Three Phase Copper Busbars (Rectangular)

In summary, the problem involves finding the force exerted on a single busbar in a 3 phase system with each phase carrying 3300A. The goal is to determine the appropriate size of busbar supports to handle the worst case scenario of induced magnetic forces between the busbars. A simplified model and FEMM simulation have been used to calculate the forces between the busbars using the force from stress tensor function. The main concern is how the offset of currents in a 3 phase system affects the forces on the busbars. Equations for calculating magnetic fields, forces, current density, and emf can be used to solve this problem. Any help or brainstorming on this topic would be greatly appreciated.
  • #1
benyzk
1
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Homework Statement


So here is the Problem :

I am Modelling an interesting problem for a project i am busy with. I need to find out the force exerted on a single busbar in a 3 phase system, with each phase carrying 3300A.

This is mainly so that i can deduce what size of busbar supports i should be using so as to handle the worst case scenario induced magnetic forces between the busbars. Assume a short circuit current of 25KA.

i am attaching a very simplified model of the problem to this post.

i have also modeled the problem using FEMM (which i will attach to the post as well) and from there i am able to calculate the forces between the busbars in the using the force from stress tensor function. For anybody who is familiar with this force, can i assume this force to be that between the busbars


Also my second problem is that the model assumes that there is 3300A running through the busbars with the Go current and -3300 running through the busbars in the return Busbars (during normal operations) However, this is not true, because in 3 phase, the currents will be offset by 120 degrees at any point in time. What effect(Magnetically) does this have on the busbars? does the force remain the same as though the current in teh phases is 0 degrees apart?




Any help / brainstorming will be greatly appreciated folks. Thank you.
 

Attachments

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  • #2
Homework Equations I'm not sure exactly what equations you would use to solve this problem, but I suggest looking up the equations used to calculate magnetic fields and forces. This includes: Magnetic Flux Density (B), Magnetic Field Strength (H), and Magnetic Induction (A/m). You may also want to look into the equations for calculating current density (J) and emf (V). These equations should give you the information you need to calculate the forces exerted on the busbars.
 

What is a three phase copper busbar?

A three phase copper busbar is a type of electrical conductor used in three phase power systems. It is made up of three parallel bars or strips of copper, which are connected at both ends to form a continuous conductor. It is used to distribute electrical power from a source to various loads in an electrical system.

What is the purpose of using copper in busbars?

Copper is commonly used in busbars due to its high electrical conductivity and low resistance. This allows for efficient transfer of electrical power. Copper is also a good conductor of heat, which helps in dissipating heat generated by the flow of electricity in the busbar.

What is the role of electromagnetic forces in three phase copper busbars?

Electromagnetic forces play a crucial role in the operation of three phase copper busbars. These forces are created when electric current flows through the busbar and interacts with the magnetic field it produces. These forces can cause mechanical stress and thermal effects, which need to be carefully considered in the design of the busbar to ensure its safe and efficient operation.

How are the dimensions of a three phase copper busbar determined?

The dimensions of a three phase copper busbar are determined based on various factors such as the magnitude of the current, the type of load being supplied, and the maximum allowable temperature rise. The dimensions are also influenced by the desired level of voltage drop and the type of cooling method used for the busbar.

What are the common types of cooling methods used for three phase copper busbars?

The most common types of cooling methods used for three phase copper busbars are natural convection, forced air cooling, and liquid cooling. Natural convection relies on the movement of air around the busbar to dissipate heat, while forced air cooling involves the use of fans to increase air circulation. Liquid cooling involves the use of a coolant, such as water or oil, to remove heat from the busbar.

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