Power Communication using Optical-fiber

Transcription

1 Power Communication using Optical-fiber Saurabh 1 Varun Kumar 2 1 Modinagar, Ghaziabad 2 Room N0.314 Ginni Hostel, KNGD Campus Modinagar, Ghaziabad ABSTRACT Power transmission is a very important tool in electrical engineering field. In power transmission it is very necessary to communicate from on location to another. For such communication it is generally desired to have a wired communication but that cost too high and also faces the problem of interference of power frequency of 50Hz /60Hz with communicating frequency of GHz. To win over this problem certain improvement in wired communication or else wireless communication can be chosen but wired communication is given priority over the wireless communication due to economic considerations and the complexity of the wireless communication. Also wireless communication use is prohibited in the radioactive zone of the nuclear plants. Here a brief detail on the power communication using Optical fiber will be presented. Keywords: optical -fiber, forward current, communication, power line 1. INTRODUCTION Power transmission and communication is the major field in electrical and electronics sectors where the work has been carried out simultaneously to improve the quality and cost effectiveness. When we talk about power we mean to convey the voltage and current of high magnitude. Since, the development and the work of the electronics, communication sector through the optical- fiber the world has seen a complete turnout. Today the data from the Pacific is send to Asia in very few seconds, this has been made possible due the presence of optical fiber cables in the Pacific Ocean and Indian Ocean. In the field of power transmission one needs to properly communicate with the other sub-stations or grids for the proper transmission and knowledge of breakdown occurrence. In such a case power line communication plays a better role and it perfectly fits in the role of a medium of communication channel. 2. POWER LINE COMMUNICATION Power line communication or commonly referred as PLC is used to carry data on conductor that is also used for ACelectric power transmission or electric power distribution. Mainly the wire we use in PLC technologies are limited to the wiring a house or building together with their outbuildings but some cross their levels by between both the distribution network and the premise wiring. Power line communication system mainly works by adding a modulated carrier signal to the wiring system. Different types of power communication are designed to operate for different ranges of frequency but generally 50/ 60 Hz is intended as the power transmission operates for this frequency only but the power line carrier are limited carry high frequencies. The wired emission are regulated time to time as they have the potential to cause radio transmissions. Data rates transfer and the distance are some of the limitation faced by PLC standard. Higher data rates generally imply for the short ranges of the area of the network but it also removes the installation of the network cabling. While utility companies use microwave and now, increasingly fiber optic cables for their primary system communication needs. 3. OPTICAL FIBER (why and How) An optical fiber is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human air. Optical fiber are more often used as to transmit the light between the two ends of the transmitting channel here fiber and find usage in optical-fiber communication, where they permit transmission over longer distances and at higher bandwidths than wire cables. Fibers are used at large scale instead of wired cables due to the fact that they faces less amount of loss in comparison to the wired cables also one reason of preference of optic fiber over the wired cable is that the optical fiber are almost immune to the electromagnetic interference. Optic fibers typically include a transparent core surrounding the transparent cladding material with lower index of refraction. Light is kept in the core by the phenomenon of total internal reflection which causes the fiber to act as a waveguide. Fibers that support many propagation paths are called multi-mode fibers (MMF) and that support the single mode are called Single mode fiber (SMF). MMF have wide core diameter and are used for the short distance communication links and where higher power must be transmitted. Volume 3, Issue 12, December 2015 Page 11

2 One important aspect of the optical fiber is that while joining the two fiber there must be minimum be losses that requires proper cleaving of the fibers and the proper splicing of these aligned fiber cores. A. Principal of operation Fig.1- Optical Fiber When light is travelling in an optically dense medium hits a boundary at a steep angle larger than the critical angle for boundary, the light is completely reflected. This is called Total Internal Reflectionfigure (1) illustrates the principal of total internal reflection. Figure 2 Total internal reflection in optical fiber This effect is used in optical fibers to confine the light rays within the core. Light travels through the core, bouncing back and forth off the boundary between the core and cladding. For the process of total internal reflection to take place light must strike boundary with an angle greater than the critical angle, only light entering the fiber with certain range of angle does not leak out. This range of angles comes under the acceptance cone of the fiber. There is a maximum angle at which the light travels in the core and sine of this angle is called as numerical aperture (NA). For single mode optical fiber NA value is comparatively small to the multi mode optical fiber. INDEX OF REFRACTION (OR) REFRACTIVE INDEX The index of refraction or refractive index is an important parameter in Total Internal Reflection. It is a way through which light s speed is measured. One knows that speed of light is maximum in vacuum with a permissible speed of m/s but one when travels from the denser medium to the rare medium the speed of light increases. Thus refractive index is calculated as the ratio of the speed of light in vacuum to speed of light in the given medium. Volume 3, Issue 12, December 2015 Page 12

3 TRANSMISSION LOSSES IN OPTICAL FIBER Transmission losses in fiber optics also known as attenuation of fiber optics. The attenuation of optical fiber decreases the intensity of light in the fiber. The medium which we generally prefer in the fiber is silica. Silica is preferred over any other medium due to its refractive index and low dispersion factor. Attenuation limits the transmission over large distances. Attenuation in optical fiber is generally caused due to the scattering and absorption phenomenon. Due to the presence of roughness and irregularities which cannot be removed practically the light rays instead of being reflected back in total internal reflection suffers scattering and absorption. As the rays intensity decreases by going through such cases of scattering and absorption the overall efficiency and accuracy of optical fiber decreases to certain extent. DESIGN CRITERIA OF FIBER OPTICS The design criteria for fiber optic is broadly classified into two categories viz. primary design criteria and additional design parameter Fig.3 designing criteria of optical fiber The primary design criteria is used for basic and fundamental information parameters to be available to the user for a reliable optic link. The first and the foremost important information needed to be specified is dispersion limitation or bit rate. The next information needed to be provided is attenuation limitation. Along with primary design criteria additional design parameter needed to be taken into consideration for better, proper, cost effective, reliable and commercially availability of optical fiber. A fundamental point to point optical communication can be diagrammatically shown as follows:- Fig. 4 point to point optical fiber communication Volume 3, Issue 12, December 2015 Page 13

4 SIMULINK STUDY OF OPTICAL FIBER The Simulink study of optical fiber is done by using matlab. Here to run a simulation we are using matlab 6.5. The user here have to define all variables linking to optical simulator. The user can modify any value of the available variable. To run a simulation required parametric value needed to be entered by the user. Then by debugging and running the file relevant values are compared with the standard data provided with in mat lab and the values are loaded within matlab work space and Simulink simulator. Following graphs are obtained when simulation is done in the matlab work space Fig. 5 output waveform of optical fiber as observed on matlab Simulink 4.CONCLUSION Communication is changing the world around us and for a fast, reliable, cost effective communication a medium should be chosen as such which could hold better effectiveness and prevent radio interference with the environment. There is a durability, safety and electromagnetic isolation which generally disturbs data transfer in wireless medium and above these factors there is also a presence of high speed data transfer which is requisite for communication parameter. REFERENCES [1.] "Light collection and propagation". National Instruments' Developer Zone. Retrieved Hecht, Jeff (2002). Understanding Fiber Optics (4th Ed.). Prentice Hall. ISBN [2.] "Definition: rip cord". Its.bldrdoc.gov. Retrieved [3.] Chirgwin, Richard (Sep 23, 2012). NTT demos petabit transmission on single fiber". The Register. Retrieved [4.] "GR-20, Generic Requirements for Optical Fiber and Optical Fiber Cable". Telcordia. [5.] "GR-409, Generic Requirements for Indoor Fiber Optic Cable". Telcordia. Volume 3, Issue 12, December 2015 Page 14

5 [6.] ]Xie Y at al., System Performance Degradation due to Nonlinear Signal Distortion in Spectral Inverter, J.Optical Comm., vol 19, no 4, 1998 [7.] Binh, L.N., ECE4405: Optical Communication Systems Notes, Monash University, 2002 [8.] Selliah, A., Simulation of Polarization Mode Dispersion Effects in A DWDM System: a time domain approach, Monash University Thesis, [9.] Coxworth, Ben (3 February 2013). "Hybrid fiber optic cable carries data and power". Gizmag. [10.] ]"Power-by-Light". Fraunhofer ISE. [11.] "IEEE P1901", Draft Standard for Broadband over Power Line Networks: Medium Access Control and Physical Layer Specifications, [online] Available: 1901/index.html [12.] IEEE ComSoc Technical Committee on Power Line Communications, [online] Available: [13.] AUTHOR SAURABHcurrently pursuing bachelor of technology in electrical disciple from Dr. Kedar Nath Modi Institute of Engineering and Technology, Modinagar Ghaziabad (UP).His Area of Interest are dedicated in Serving for better future establishment of society regarding use of optical instruments in power system. His role focuses in how we can use optical fiber in communication for betterment of communication in the electrical fields such as power plants. Varun Kumar currently pursuing bachelor of technology in electronics and communication disciple from Dr. Kedar Nath Modi Institute of Engineering and Technology, Modinagar Ghaziabad (UP).His Area of Interest are dedicated in Serving for better future establishment of society regarding use of communication. His role focuses in how we can use optical fiber in communication in different field of life. Volume 3, Issue 12, December 2015 Page 15