UNDERGROUND CABLES: Opportunity for sustainable development

Today, majority of the world's population live in cities and towns. With the rapid urbanization it is estimated that in the next 10-15 years there will be a further surge in urban residents while rural population will diminish rapidly. To ensure the rural population receive uninterrupted and continuous share of electricity for the process of urbanization these upgrades need to be sustainable in the long run. Therefore, the right index of urbanization can be recognized by sustainable development.

Infrastructure should be considered as one of the shaping forces for urban and regional development. In developed areas, underground framework may offer one of the few acceptable ways to encourage and support more sustainable growth. A well-maintained, resilient, and adequately performing underground infrastructure is essential to future sustainability of cities. Much, however, can be done to improve the sustainability aspects of underground facilities themselves.

Electrical cabling is the nerve of any electrical network and is one such critical, yet unfocused aspect for the process of modernization. They are also the most vulnerable to failures. While most failures can be attributed to improper selection of cables, suitable selection is not only a key for reliability of power supply and safety of devices as well as human beings but also avoids loss of assets and saves costly business hours. Understanding the importance coupled with demand of rapid transformation, developed countries have increasingly shifting effort towards underground cabling as a method of power transformation.  Some countries which have exclusive medium voltage cable distribution grids like Singapore, Netherlands have a very reliable underground public power supply.

Apart from the obvious aesthetic advantages of improved appearance and ecological maintenance of property, underground cable transmission systems have many advantages over overhead lines. Below are some points to consider while planning to opt for underground cabling.

• The initial cost of underground cabling is high. Underground cables costs approximately three times more as compared to that of overhead lines. However, since underground cables are covered by insulation layers they are not exposed to damage or the environment. Ensuring the chances of developing faults are low and require less maintenance in the long run.  Underground systems generally have longer life expectancy.
• Underground cables are less susceptible to environmental hazards and severe weather conditions such as heavy rain, thunderstorms, lightning, extreme wind and more. Service is uninterrupted by these factors when the cables are buried below the ground. A practical example can be seen with Mumbai- consumers here enjoy virtually uninterrupted power through heavy rains, thunderstorms and high winds.
• In case of the failure or damage in underground cables, it is hard to discover and fix the wire breaks. Rectifying the problem could be a time-consuming exercise. This could be overcome if necessary, precautions and systematic planning is considered prior to the installation of underground cabling.
• The underground power cables are designed to reduce the power losses so there is very less voltage drop. They have decreased the EMFs (Electric and Magnetic Fields) and therefore removes the potential health issues.
• Once underground the underground cable system is setup, it is very hard to steal, and also very hard to sabotage or make illegal connections.
• Underground cabling setup requires a narrow surrounding area as compared to the overhead line. They are suitable for congested urban areas where overhead lines may be difficult or impossible to install. They have minimal visual pollution and aesthetically pose no danger to low flying aircrafts or wildlife and trees can grow unhampered. They also prevent accidents and the hazard of people being exposed to high-voltage power, or from poles becoming hazardous to vehicles, or from fallen poles and live wires
• Land being a valuable and scarce resource, particularly in urban areas. Underground cable systems do not restrict the construction of buildings and other structures over and around them.

Burying power cables has become a critical aspects of distribution business in India after the recent cyclones that have battered the electric infrastructure of different parts of the country. Massive power infrastructure in the state of Odisha, including two lakh electrical poles, 84,000 kilometers of low tension wires, 11,000 distribution transformers and four 132 KV grids were damaged in the rare summer cyclone that plunged more than 25 lakh families into darkness. To overcome disruptions in power distribution and withstand any kind of weather conditions, over the last few years, states such as Tamil Nadu, Maharashtra, Odisha and Karnataka have started planning, executing the replacement of high-tension lines with underground cables in a phased manner.

Underground cables are suited for places where it is difficult to use overhead lines due to obstructions and dangers presented by the overhead lines. They offer an affordable and justifiable solution for critical parts and in some cases the entire length, of overhead high voltage power lines. While underground cables are more expensive to install than overhead lines, however, the maintenance cost of underground system is very low and also free from interruption of natural catastrophes. Both overhead and underground has its advantages as well as disadvantages. However, the overall advantages of underground cables outweigh their disadvantages.

- Deepak Chhabria

Chairman, Finolex Cables

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