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From ancient times to modern times: How has underground power transmission technology evolved?
The development of underground power transmission systems is the result of technological progress and demand driven. From the initial simple cables to today's complex networks, the rapid progress of this technology has had a profound impact on our lives. Compared to traditional overhead power lines, underground power lines have demonstrated significant advantages in reducing the risk of wildfires and reducing power outages during severe weather. As the public attaches great importance to safety and environmental beauty, underground power transmission is gradually becoming more and more popular.
Historical evolution
The history of underground power transmission can be traced back to ancient mining techniques and undersea telegraph cables. Cables were used in Russia to detonate mining explosives as early as 1812, and in 1850 they were used to transmit telegraph signals across the English Channel. With the development of power systems, the application of underground cables has begun to expand. Thomas Edison used underground DC "street pipes" in his early electricity distribution systems, initially insulated with burlap and later with rubber insulation.
Over time, advances in insulation and manufacturing techniques have led to the widespread use of underground cables.
Comparison of the advantages and disadvantages of underground cables
Compared with overhead cables, underground cables can effectively reduce the impact of high-voltage power lines on the landscape, especially in cities or areas with expensive land and environmentally sensitive areas. According to a 2024 Wisconsin Public Service Commission report, a 69-kilovolt overhead cable costs $284,000 per mile, while the corresponding underground cable costs up to $1.5 million. As a result, utility companies often exercise caution when selecting buried cables.
Advantages of underground cables
Underground cables have the following significant advantages over overhead cables:
- Not easily affected by severe weather, such as lightning, hurricanes, and ice and snow storms.
- Reduce the risk of fire.
- Reduce the impact of surrounding electromagnetic radiation.
- No harm to low-flying aircraft or wildlife.
Underground power distribution systems make urban design more flexible and increase the potential for greening within limited space.
Disadvantages of underground cables
However, the construction and maintenance of underground cable systems is not without its challenges. The cost of laying underground cables is usually several times that of overhead power lines. Not only is the material cost high, but the construction is also more complex. Because fault detection and repair in underground cables often takes longer, this could result in longer outages. In addition, ground construction will also affect traffic and cause inconvenience.
Technical methods
Installation methods for underground cables include:
- Horizontal drilling: Drilling starts from the ground to form an arc-shaped channel.
- Trenching and burying: dig trenches, lay out and cover cables.
- Conduit Bank: Uses parallel conduit set up with filler to protect cables.
Regulations and policies
There are also differences in the management of underground power transmission in different regions. For example, Europe has clear regulations on the cost recovery of underground cables, and the cost of undergrounding is amortized through corresponding user prices. In the United States, California's Public Utilities Commission allows undergrounding projects to be implemented under different circumstances, with some shared by users.
Whether it is in the design, construction or operation stages, the development of underground electrical transmission systems requires multi-party collaboration and technological innovation.
Conclusion
With the increasing global awareness of sustainable development and environment, underground power transmission technology will continue to evolve and innovate to meet future society's needs for safety and aesthetics. In the future, can we see more cities moving their power systems underground to improve city appearance and living environment?
