Do transmission lines sway due to fluctuations in the current being transmitted?
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Our company has a power transmission line (copper bar) that transmits direct current, with a current level of around 15,000 A. However, for certain reasons, the current fluctuates to some extent, ranging from 12,000 to 15,000 A. What can be observed on the copper bar is shaking, which is quite alarming. The manufacturer says it is caused by these current fluctuations. Does this really be the reason?
High currents (especially direct current) cause significant temperature rises; the bolts used to connect the busbars must be made of the same material as the busbars themselves, to ensure that both have the same coefficient of expansion. I have never seen high-voltage busbars in operation (due to safety reasons). I have seen many low-voltage busbars, and I have also dealt with the problem of overheating caused by excessive contact resistance at the connections. But I have never seen busbar vibration caused by high current. From the perspective of maintenance, busbars must be securely fixed; it is recommended to check the material and tightness of the connection bolts.
When an electric current flows through a wire, a magnetic field is inevitably generated; this magnetic field exerts a force in contrast to the Earth’s magnetic field. This effect is not noticeable when the current is small. Especially when the current is large, and particularly the greater the change in current, the magnetic force (also known as electric field force) becomes more pronounced. The resulting phenomenon is the swinging or vibrating of the cable. Furthermore, when multiple wires operate in parallel, high currents can exert forces on one another, causing them to swing or vibrate.
It might be due to the effect of electric power; is the cross-sectional area sufficient? With or without balance reactor