Optical fiber communication in power distribution automation applications on paper
The first phase in the evolution of Cnc machining communication networks is dominated by the wide spread of telephony and covers over 90 years . However ,the telegraph preceded the telephone by more than 30 years and the teletypewriter by half a century . In1844, Samuel Morse , the telegraph’s inventor ,sent the first telegraph message from Washington D.C. to his coleague Afred Vail in Baltimore, Maryland. Shortly after the invention of the telephone by Alexander Grahan Bell in 1876 ,it was realized that telephone wires had to converge on central points where telephone-to-telephone connections could be made .These points were manual switch-board, Staffed by operator .This was followed by the introduction of electromechanical switching and in 1889,Almond B.Strowger invented the first two-motion step-b-step switch.
The golden age of automatic telephony occurred after Word War ∏ when the entire long-distance network was automated .
The invention of the transistor spurred the application of Electronics to switching systems and led to the deployment of the first electronic switching in the late 1950s . Electronic switching made it possible to design and build switches with greater capacity.
The second phase of networking ,which occurred in the 1960s ,included three major milestones:software switching ,digital transmission ,and satellite deployment.
The third phase of the evolution of communication networks occurred in the 1970s and is characterized by the introduction of data networks and packer switching technology. To achieve compatibility between computers and packet-switched network ,the international Telegraph and Telephone Consultative Committee (CCITT from the French acronym established a word-standard protocol, called X.25 in 1976. This phase of networking is also characterized by the introduction and wide acceptance of local area networks(LANs). The invention of the laser (which stands for light amplification by simulated emission of radiation ) in 1959 led to major technical developments in the field of optical communication. 1970, Corning Glass Works reported on the first low-loss optical fiber (dopedsilica clad fiber ) that achieved 20 dB/km loss.
The fourth phase of communication networking ,which began in 1980, is
characterized by the availability of the integrated services digital networks (ISDN) and mobile communications.
With the development of national economy and people's living standards improve, people's growing demand for electricity, while the reliability and power quality of power supply put forward higher requirements. Feeder Automation is the reliability of power supply distribution network systems to improve the most direct and effective means of technology. Countries has increased in recent years on the city network and the transformation of rural power network, power supply bureaus of the major domestic investment in distribution automation is also increasing. Achieved in the distribution network automation process, we found that communication problems is a difficult problem. In this, just from the fiber-optic communication networks in automation applications with little knowledge about and experience.