Skip to main content

SUPERCONDUCTORS: LOSSLESS TRANSMISSION OF ELECTRICITY

What are superconductor’s roles for lossless power distribution?
All the power losses that occurs in an electrical system boils down to the fact that all of the components needed to transmit electrical power has resistance. Power losses is dissipated in the form of heat in the electrical system happens because there is an opposition to the flow of current called resistance.
Given this fact, we may wonder what if resistance does not exist in any electrical components. By then we can assume that our system would inevitably be a 100 per cent efficient one. Utilities would no longer worry about technical losses in its system.
Fortunately, we now have that technology readily available for use in the form of Superconductors. Superconductors are defined as materials that have no resistance to the flow of electricity and are one of the last great frontiers of scientific discovery.
Not only have the limits of superconductivity not yet been reached, but the theories that explain superconductor behavior seem to be constantly under review. In 1911 superconductivity was first observed in mercury by Dutch physicist Heike Kamerlingh Onnes of Leiden University. When he cooled it to the temperature of liquid helium, 4 degrees Kelvin (-452F, -269C), its resistance suddenly disappeared. The Kelvin scale represents an "absolute" scale of temperature.
Thus, it was necessary for Onnes to come within 4 degrees of the coldest temperature that is theoretically attainable to witness the phenomenon of superconductivity. Later, in 1913, he won a Nobel Prize in physics for his research in this area.
Superconductivity, on the other hand, is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature.
The electrical resistivity of a metallic conductor decreases gradually as temperature is lowered. In ordinary conductors, such as copper or silver, this decrease is limited by impurities and other defects. Even near absolute zero, a real sample of a normal conductor shows some resistance.
In a superconductor, the resistance drops abruptly to zero when the material is cooled below its critical temperature. An electric current flowing in a loop of superconducting wire can persist indefinitely with no power source.
Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state. The occurrence of the Meissner effect indicates that superconductivity cannot be understood simply as the idealization of perfect conductivity in classical physics.

Sources: wikipedia, www.superconductors.org

Comments

Popular posts from this blog

PARTS OF A POWER TRANSFORMER

What are the name of the basic parts of a Power Transformer? We can not deny the fact that only a handful of electrical engineering students are presently familiar with power transformers especially on what it looks like. Unlike a transformer we found in our homes, a power transformer’s appearance and construction is somewhat more complicated. It is not just a simple winding with a primary and secondary terminal although basically any transformer has one. The function that a power transformer plays in an electrical system is very important that an electric utility can not afford to loss it during its operation. Our discussion here will focus more on the basic parts and functions of a power transformer that are usually tangible whenever you go to a substation . Although not all power transformers are identical, nonetheless they all have the following listed parts in which the way of construction may differ.

ELECTRIC MOTOR FRAME SIZE STANDARD SPECIFICATIONS

ELECTRIC MOTOR FRAME SIZE STANDARD SPECIFICATIONS How is electric motor frame size being specified? Motor frame dimensions have been standardized with a uniform frame size numbering system. This system was developed by NEMA and specific frame sizes have been assigned to standard motor ratings based on enclosure, horsepower and speed. The current standardized frames for integral horsepower induction motors ranges from 143T to 445T. These standards cover most motors in the range of one through two hundred horsepower. Typical example of where you can locate the frame is shown in Fig 1.2.D – Frame No. The numbers used to designate frame sizes have specific meanings based on the physical size of the motor. Some digits are related to the motor shaft height and the remaining digit or digits relate to the length of the motor. The rerate, or frame size reduction programs were brought about by advancements in motor technology relating mainly to higher temperature ratings of insulating mate...

ELECTRIC MOTOR NAMEPLATE SPECIFICATIONS

How do we interpret an electric motor nameplate? Motor standards are established on a country by country basis.Fortunately though, the standards can be grouped into two major categories: NEMA and IEC (and its derivatives). In North America, the National Electric Manufacturers Association (NEMA) sets motor standards, including what should go on the nameplate (NEMA Standard MG 1-10.40 "Nameplate Marking for Medium Single-Phase and Polyphase Induction Motors").