What methods are used for the installation of the flexible cable leads for the wife-carrying ducts?

When installing bushings for transformers of 110kV and above, the use of soft cable leads can be labor-intensive and time-consuming, often resulting in lead bending and even partial strand breakage. To address this issue and improve work efficiency, a specialized tool for lead installation—the lead pulling pulley device—can be developed.

First, select 25×25 angle steel and bend it into two door-shaped frames with a height of 350mm. These frames should possess sufficient strength and rigidity to withstand the forces generated during the installation process. Next, weld the frames onto the outside of a clamp, which is 10–15mm larger than the outer diameter of the bushing oil conservator. This design ensures that the frames are securely fixed to the bushing, preventing loosening or displacement during operation.

Then, install a pulley of size 60×16×20 near the top end between the two frames. The pulley should be chosen based on its load-bearing capacity and sliding performance to ensure smooth operation when pulling the lead. The installation position of the pulley should also be carefully determined to ensure that the pulling rope can pass through smoothly and minimize friction.

Before lifting the bushing, attach the clamp to the top of the bushing oil conservator and secure it with bolts. This step is crucial because the stability of the clamp directly affects the smooth progress of the entire installation process. Next, thread a nylon rope through the pulley and insert the rope into the bushing until the rope head emerges from the lower end of the bushing. During this process, ensure that the nylon rope is long and strong enough to bear the weight of the lead and will not break during pulling.

When the bushing is lifted to the installation hole, firmly tie the exposed rope head to the upper end of the soft cable lead. At this point, the rope can be pulled from the ground as the bushing descends, allowing the lead to pass vertically through the bushing and reach the top. This method effectively prevents the lead from bending while passing through the bushing, thereby protecting the integrity of the lead.

To further ensure the success of the lead installation, special attention should be paid to the lead near the equalizing ball inside the bushing to ensure it smoothly enters the conduit of the bushing. This is crucial because the path near the equalizing ball is relatively narrow and prone to lead coiling. If the lead coils in this section, it will not only increase the difficulty of installation but may also subject the lead to additional stress during operation, thereby affecting its service life.

In summary, using the lead pulling pulley device can significantly enhance the efficiency and quality of transformer bushing lead installation. Through scientific design and careful operation, it is possible to effectively prevent lead bending and partial strand breakage, ensuring the lead passes smoothly through the bushing. This approach not only saves labor and time costs but also improves the overall reliability and safety of transformer installation.

LuShan, est. 1975, is a Chinese professional manufacturer specializing in power transformers and reactors for 49 years. Leading products are single-phase transformer, three-phase transformers, DC inductors, AC reactors, filtering reactor, expoxy resin high-voltage transformer and intermediate, high-frequency products. Our transformers and reactors are widely used in 10 application areas: rapid transit, construction machinery, renewable energy, intelligent manufacturing, medical equipment, coal mine explosion prevention , excitation system, vacuum sintering, central air conditioning.

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