Copper busbar shearing machine when process busbars.there are some tips need to pay attention to.Like selection of busbar material and shape.There are three kinds of materials for hard busbar: copper, aluminum and steel. Copper has the characteristics of low resistivity. high mechanical strength and good corrosion resistance. but the reserves of copper in China are not much, and it is more valuable. The conductivity of aluminum is about 60% of that of copper. Aluminum welding is more complex.The section shapes of the rigid busbar are rectangle, groove and tube.and also for welding joints busbars need the distance from the edge of the supporting insulator busbar. clamp plate shall not be less than 50mm.and the butt weld shall be reduced on the same busbar.the distance between the two welds shall not be less than 200mm.
1、 Selection of busbar material and shape when processed by busbar machines
The busbar materials processed in the bus bar machine include copper, aluminum, steel, etc. Copper has high conductivity, corrosion resistance, light aluminum and low price. When selecting the busbar material. the technical policy of “replacing copper with copper” shall be implemented. Except for the special environment where only copper is allowed in the regulations, aluminum busbar shall be used. The steel busbar is used in places where the load current is very small .and the annual utilization hours are small.
busbar shape includes rectangle, tube and stranded wire. The indoor voltage is less than 35 kV, and the outdoor voltage is less than 10 kV. Usually, the rectangular busbar is used, because it has the advantages of better cooling conditions.smaller AC resistivity and smaller cross section under the same conditions than the solid round busbar. Considering the cooling condition, skin effect, mechanical strength and other factors.the rectangular busbar usually adopts high temperature, high temperature and low temperature
Rectangular material with a width ratio of 1 / 5-1 / 12.
For outdoor distribution busbar of 35kV and above, multi strand stranded wire (such as steel core aluminum stranded wire) and tension insulator are generally used. In the outdoor distribution equipment with voltage higher than 35 kV, the busbar with circular section is often used.such as tubular busbar and multi-core stranded wire, instead of rectangular section busbar.which is mainly to prevent the busbar from corona.
2、 Selection of conductor material and conductor section shape of busbar will be used on bus bar machine
When the busbar is processed by the copper busbar shearing machine
, pay attention to the selection of the conductor material and the conductor section shape of the busbar:
Selection of conductor materials which will use on copper busbar shearing machine
There are three kinds of materials for hard busbar: copper, aluminum and steel. Copper has the characteristics of low resistivity, high mechanical strength and good corrosion resistance. but the reserves of copper in China are not much, and it is more valuable. The conductivity of aluminum is about 60% of that of copper. Aluminum welding is more complex, and its mechanical properties .and corrosion resistance are worse than that of copper. However, aluminum has low price and light weight. Steel is cheap, mechanical strength is good, welding is simple. but skin effect is serious. If the load working current is too large. it is often used in the connecting wire of grounding grid.
Selection of conductor section shape will be used on bus bar machine
The section shapes of the rigid busbar are rectangle, groove and tube. Rectangular busbar has large heat dissipation area, high material utilization rate, good bending strength when bearing vertical bending.but large skin effect, the surrounding electric field is very uneven. easy to generate corona.so it is only used in the indoor power distribution device with 35kV and below and continuous working current of 4000A and below. The channel busbar has small skin effect, good cooling condition and high mechanical strength. It is commonly used in the distribution equipment with 35 kV and below and continuous working current of 4000 a-8000a.
The tubular busbar has large curvature radius, good material conductivity utilization, heat dissipation, bending strength and rigidity.and small skin effect. It can be used for the large current busbar with a capacity of more than 8000A. as well as for the outdoor distribution equipment with a capacity of more than 220kV and longer span.
3、 Requirements for butt welding joints of bus bar which will use on copper busbar shearing machine
For the busbar processed in the copper busbar machines, the welding joints shall meet the following requirements:
The distance from the edge of the supporting insulator busbar clamp plate shall not be less than 50mm.and the butt weld shall be reduced on the same busbar; the distance between the two welds shall not be less than 200mm. For butt welds of straight sections on different pieces of the same phase busbar, the staggered position shall not be less than 50 mm. and the welded parts shall not be bent.
Fasteners for connecting busbars shall be galvanized bolts, nuts and washers. When the busbar is horizontally placed, the bolt shall be penetrated from the bottom to the top. and the length of the probe bolt shall be suitable to expose 2-3 threads of the nut screw thread. In other conditions, the nut shall be placed on the maintenance side. and washers shall be padded on both sides of the bolt, with a clear distance of more than 3mm between adjacent washers. and the nut side shall also be equipped with spring locking or locking nuts.
4、 After the fault, the busbar can’t be used any more. At this time, it can’t be used until it is reprocessed by the busbar processing machine in the factory. Here are several common faults of the lower busbar.
- Due to poor contact and increased contact resistance of the busbarbar joint. it will generate heat, which will cause the joint to burn red in serious cases.
- The supporting insulator of busbar reduces the insulation resistance of busbarto ground due to poor insulation. In serious cases, it will cause flashover and breakdown.
- When the large short-circuit current passes through the busbar. under the action of electric power and arc flashover, the busbar will be bent, broken and beaker. and the insulator will be broken.