Introduction of vibration analysis of aluminum tube busbar in substation
The power distribution device of the aluminum tube busbar occupies less area, has a clear layout and a simple structure, so it is used by more and more substations. Since the substation adopts the aluminum tube busbar to operate, it has been found that the phenomenon of breeze vibration occurs in many space partitions. In the long run, it will inevitably lead to fatigue damage to the supporting hardware of the aluminum tube and the fracture of the supporting insulator.
Causes of vibration analysis of aluminum tube busbar in substation
When a stable breeze blows perpendicular to the axis to a wire with a circular cross-section, the airflow on the downwind side becomes chaotic and an airflow vortex (called Karman vortex train) appears, which alternately and continuously appears on the upper and lower sides of the wire. When the period of the resulting force is approximately consistent with the natural frequency of the wire body, the phenomenon of breeze vibration occurs. Therefore, the aluminum tube busbar has a slight wind vibration.
It will only occur under specific circumstances where the following three conditions are present at the same time:
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1. The outside breeze must have sufficient excitation energy and last for a period of time (such as 15s).
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2. There must be stable wind perpendicular to the axis of the aluminum tube busbar. Usually only when there is a relatively open area in front of the power distribution device
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possible.
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3. The natural frequency of the busbar must be relatively low, because a stable laminar flow can only be generated when the wind speed is below 5-6 m/s. correspond
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The frequency of vibration caused by this wind speed range is 5-6 Hz.
Preventive measures of vibration analysis of aluminum tube busbar in substation
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1. When designing the substation, avoid the vertical wind according to the local meteorological conditions.
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2. The use of long bracket support can shorten the free span of the busbar, improve the rigidity, and avoid the low frequency of breeze vibration.
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3. Place a slack steel-cored aluminum stranded wire in the aluminum tube busbar. When the aluminum tube busbar vibrates, it will impact the tube wall to absorb the vibration. The optimal weight ratio of steel-cored aluminum stranded wire and aluminum tube is 12% (due to the improvement of the electric field distribution at the end of the busbar during installation, most of the aluminum tube ends have been closed, and it is not economical to place wires in the aluminum tube at this time).
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4. An anti-vibration hammer can be installed at the space partition of the busbar, which is simple and economical. Since the anti-vibration hammer was installed on the vibration part of the busbar of this station for more than a year, the phenomenon of breeze vibration of the busbar has not been found again.
