Beyond the increased cost of undergrounding transmission lines 10 to 30 times greater than overhead construction depending on voltage , the main issues are heat and environmental impacts. When high-voltage energy flows through a conductor, resistance in the conductor generates waste heat or transmission losses.
The higher the energy transmitted, the more heat is generated. With overhead transmission lines, the air surrounding the lines acts as an insulator and absorbs this waste heat. In underground transmission lines other mediums must be used to dissipate this heat, which to-date has restricted the undergrounding of transmission lines to voltages less than kV except for very short distances.
Another consideration of underground lines is the ground disturbance caused by the tunnels through which the transmission line runs. Instead of impacting the ground only at tower footings, underground transmission construction requires extensive excavation and can disrupt habitats or water resources. All Rights Reserved. Subscribe Log In Logout. News Ticker. At a steam generating plant, the fuel coal, nuclear or biomass heats water to make steam and drive a turbine.
In a combustion turbine, the fuel gas or oil is burned and the hot gas drives a turbine. When it comes to danger, amps — the measure of how much current travels through the body — is more important than voltage. Electricity can jump several feet in order to complete this task, so safeguards were needed to contain the electricity in power lines from leaving their paths.
The glass, ceramic or plastic caps found on some utility poles prevent the flow of electricity — or information when discussing communication lines — from leaving the wire and following the pole into the ground. Companies first started producing these caps, called insulators, in the s to allow electricity to travel over large distances.
These are not the same as those brightly colored balls or other attachments hung along long, high utility wires. These markers or marker balls act as a warning to low-flying aircraft. Residents often assume power lines are insulated to protect people from shock in the event of a line breaking and falling to the ground. Surprisingly, less than 10 percent of residential power lines are insulated, so why do people have this misconception? They often mistake the weatherproof coating on the outside of electrical lines for insulation, but this is used to protect the naked wires inside, not to protect people.
When insulation is installed, two things happen:. The drawbacks outweigh the benefits of insulating lines, so many companies opt out of the expense. According to the California Public Utilities Commission, about 10 percent of wildfires are started by power lines. This happens when:. This is one reason utility companies, municipalities and property owners trim back trees around power lines.
Some wildfires have raged unchecked over tens of thousands of acres, killing people and causing massive destruction. Unfortunately, placing all existing lines underground would be too expensive and destructive. Underground placement is a safer option for future developments, however, for safety and as a component of community beautification.
Eventually, the standard height of power lines could be a negative number. In this way, power lines are deceptive. They might look perfectly safe, but can be deadly to approach. The reason birds and other small animals can sit on a power line without getting hurt boils down to laziness.
Currents take the fastest, easiest path to where they are going. It would take needless time for electricity to leave a wire, travel through a squirrel and return to the line. Real estate studies from around the nation are mixed about the size of the impact on property value. Expensive homes seem to take more of value hit than lower-cost homes. And it is also possible the impact on your home or property may be insignificant.
However, if your home is near a power transfer station or has a transmission line easement, then there is likely to be a more significant impact. Or, if your home is in an area where a new power line is going through, your property value may see a significant drop. In any case, one must always be aware of the risk to any future sale of the property if there is a perception of a problem, whether fact-based or not. If you are concerned about your exposure to electromagnetic sources around you, including power lines, you can measure the field strength with a device called a gaussmeter.
0コメント