【正文】 ical fibers areusually more to strengthen the core protecting materials fixed materialsbined to form the transmission line MODEM to be pleted by optical signal and digital signal conversionbetween. Fiber MODEM generally have more than one data port to transfersynchronous or asynchronous signals. Communication speed up to 2Mbps orhigher with monly used work munication rate is generallysynchronous asynchronous 19200bps N 64K or less. It is sufficient to meet theneeds of distribution work munication。 6 結束語 在實際的配網自動化的通信系統(tǒng)，必須構建一個成本低、收效高的雙向通信系統(tǒng)，用可以接受的費用在可靠性和信息流量方面提供非常高的性能。這一功能使通信的可靠性大大增強。單模光纖比多模光纖傳輸距離長，目前一般地，光信號在多模光纖內可傳 6km 左右，在單模光纖內可傳 30km。 2經濟性： 考慮到配電網系統(tǒng)的總體經濟效益，通信系統(tǒng)的投資不應過大，力爭充分利用現(xiàn)有的主網通信資源，進行主、配網整體規(guī)劃，避免重復投資。配網饋線自動化是配網系統(tǒng)提高供電可靠性最直接有效的技術手段之一。 通訊網絡的第二個階段發(fā)生在 20 世紀 60 年代，包含三個主要的里程碑：軟件，數字交換，和衛(wèi)星的發(fā)射部署。但是，電報領先于電話 30 多年，打字機領先于電話半個世紀。 第二次世界大戰(zhàn)之后，整個長途網絡自動化后，自動電話進入了黃金期。康寧光纖實驗室發(fā)布第一個低能耗光纖，可以實現(xiàn) 20Db/km 損耗。配網系統(tǒng)擁有眾多的開閉所、配電變壓器、柱上斷路器，要對這些設備進行監(jiān)控就需要許多 FTU 和 TTU，同時這些 FTU 隨配電設備安裝，地域分布廣，通訊節(jié)點分散。 3 光纖通信 自激光器和低損耗光纖問世以來，光纖通信系統(tǒng)以其技術、經濟上無可比擬的優(yōu)越性而迅速崛起，并風靡全球。通信速率可達到 2Mbps 或更高，配網常用的通信速率一般為同步 N64K 或異步 19200bps 以下。 實際工程設計中，充分考慮到電力通信專網拓撲結構的復雜性， SDH 傳輸系統(tǒng)可以采用多達 126 個 E12M 口全交叉連接和雙主光環(huán)多光分支的設計思想。 In addition there is a doubleloop fiber optic MODEM with selfhealing function. This feature greatly enhance the reliability of the munication. the signalis not affected while the main station to send the appropriate alarm andpositioning signals so that maintenance personnel section of cable fault the characteristics of optical fiber municationLarge capacity optical fiber munication with the munication theattenuation is small not afraid of lightning antielectromagic interferencecorrosion resistance confidentiality reliability and easy installation but therelatively high investment costs especially for inner city buried cable lines fiberlaying construction costs will be optical fiber munication implementations in distribution worksOptical fiber munications work formation is very flexible and can frame intoa star chain tree mesh single fiber work dualfiber work ringmultibranch multiring intersection tangent and other multiring to the characteristics of distribution automation systems fiber optic ring usually made up of work and puter local area work connectiondata She Ji practical engineering the fully take into account the special worktopology power structure o