Underground Electrical Cable Vs Overhead Lines

The design and construction of underground transmission lines differ from overhead lines because of two significant technical challenges that need to be overcome.

Underground electrical cable vs overhead lines.

With overhead lines you have to watch that tall trucks farm implements augers and other tall pieces of equipment don t get tangled in them. With underground feeders you have to watch out when you are digging. Significantly less cost especially initial cost. Much less visual clutter.

Voltage drop there is more voltage drop in the overheads due to the fact that their cables are of much smaller diameter than underground cables for the same power delivery. Overhead lines are nothing but a conductor laid on the top of earth by installing transmission tower. Safety less chance for public contact. To minimize a large charging current produced in high voltage cables the length of the cable should be minimized.

According to the may 2011 paper underground electric transmission lines published by the public service commission of wisconsin the estimated cost for constructing underground transmission lines ranges from 4 to 14 times more expensive than overhead lines of the same voltage and same distance. Longer life 30 to 50 years vs. Cost of underground cables e g. 1 providing sufficient insulation so that cables can be within inches of grounded material.

Overhead lines interfere with communication lines that are in close proximity have corona discharge radio and tv interference which does not happen with the underground lines. Overhead line is a source of electrical and magnetic field where underground cables have the magnetic fields screened so only electrical fields might be an issue in this case. Undergrounding is the replacement of overhead cables providing electrical power or telecommunications with underground cables it demonstrates the higher technology in developed countries for fire prevention and to make the power lines less susceptible to outages during high wind thunderstorms or heavy snow or ice storms. Digging around underground feeders is a disaster waiting to happen.

It is difficult to find and repair the wire breaks in case of failure of system. In overhead line inductor plays major roles and in underground cable the capacitor plays major role. Following are the disadvantages of underground transmission. Reliability shorter outage durations because of faster fault finding and faster.

Aesthetics underground s number one advantage. Hvdc are three times higher compare to overhead lines e g. The electric field of the cable lines is fully limited by the metallic screen. Moreover laying or burying cost of underground lines are greater compare to overhead lines.

And 2 dissipating the heat produced during the operation of the electrical.