Design Of A Semi-automatic Block Information Optical-electrical Conversion And Transmission System

Block is one of the main security measures for the railway system to prevent collision or rear-end collision of trains. The exterior block line in the semi-automatic block system under Jinan Railway Bureau is only equipped with loop cables and has a lot of problems, such as overtime service, electrical performance degradation and difficulty in maintenance. At present, extensive research has been carried out to improve the electrical characteristics of the block cable. However, high cost prevents it from practical application in the near future.The Communication Department of Jinan Railway Bureau has ample optical cables and digital transmission channels. It has computer rooms in all stations along the railway, and all the computers constitute a digital transmission network based on 10G backbone network. Every digital transmission facility has an audio communication interface. If the existing digital communication transmission channel can be used to transmit the semi-automatic block information by a specific signal along the stations, we can provide a stable backup channel for cable transmission.In this work, a semi-automatic block information optical-electrical conversion and transmission system was designed. The system consisted of a semi-automatic block information transmission apparatus (referred to as 64D transmission equipment), SDH optical transmission equipment and network monitoring software.Firstly, hardware of the 64D transmission equipment including network monitoring unit, transmission unit, power supply unit (main and spare ones) and protection unit was designed. Secondly, the 64D chassis and the 64D communication protocol format were designed as well. Furthermore, the operating environment of the network monitoring software was described, and the flow diagram of the main functions, the user interface, and the operating procedures and data structure of this software were also designed. The software can be used in the 64D transmission equipment for real-time monitoring including monitoring information, alarming information and parameter configuration.This system can realize real-time switch between electrical cable and optical cable (main and spare ones), block signal (digital signal) coding and decoding, channel state network monitoring and management, information sampling and other functions. It was suitable for single or double line semi-automatic block section.