Heartbreak at a busbar
There is no love lost at a busbar, when things get too hot it can only end in catastrophe. A busbar is an electrical component used to carry high-voltage power from a source to the loads. More than just a wire, a busbar is able to cope with higher frequencies and the accompanying eddy currents.
Palpitations send them into a spin (circulation)
A rapidly changing electromagnetic field i.e. that generated by an AC current, encourages electrons to circulate inside the conducting material. This circulation is what we refer to as an eddy current.
So they like to circulate, can’t we just let them be sociable?
If only that were possible. Circulating electrons have a habit of bumping into things, and each bump makes them a little warmer. If left to circulate for too long or in a material that just isn’t able to cope we can end up with a thermal meltdown.
Sparks fly with High voltage but be aware of your blood pressure
When the arteries in our bodies are healthy, they constrict and expand to help maintain the blood pressure. As we age, their walls stiffen. Additionally, people who suffer from high cholesterol will have deposit build-up in their arteries that restrict blood flow. This resistance to flow elevates the blood pressure as the heart pumps harder to force the blood around the body. Similarly, an electric circuit operating at higher frequencies induces AC effects (eddy-currents and proximity), which require a higher voltage to drive the same current. If the design of the system can not cope with high-frequency effects, it must derate it. Derating is standard practice for in-service induction motors and transformers. Alternatively, we can isolate these frequency effects from the system using filters.
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While there is a similarity between the increased blood pressure, due to deposits in the blood vessels, and the higher voltage required to overcome the AC effects, the circularity system has one advantage over an electrical system. The blood vessels can change their diameter to allow more or less blood through to maintain the blood pressure. Conversely, an electrical circuit is fixed, and therefore, engineers have to design robustness and safety into the system from its conception.
The engineering challenge when designing a busbar
Therefore, busbar analysis dictates simultaneous consideration of multiple power sources and sinks to reproduce operational and failure modes. That is, support for various voltages and currents (DC, AC, and PWM), multi-terminals, active (switches), and passive (RLC) components. After a complete busbar analysis incorporating the power loss and temperature hotspots, engineers can size busbars and protective devices based on their current carrying capacity. However, several common misconceptions and assumptions when conducting an analysis can be fatal to the product.
In a recent blog I cowrote with siemens experts we looked at some of these misconceptions and showed how software can help prevent oversight from becoming a safety-critical mistake.
The original blog can be found here
Other related blogs I have worked on
Why are power transformers so noisy? here
What’s new in Simcenter SPEED, Simcenter Motorsovle, and Simcenter MAGNET 2022.1. here
Electromagnetic motors are the world’s biggest energy consumers. here
