This paper presents the design of hierarchical communication network for traction power supply supervisory control and data acquisition (SCADA) system. Some key points, such as data transmission synchronization, datab...This paper presents the design of hierarchical communication network for traction power supply supervisory control and data acquisition (SCADA) system. Some key points, such as data transmission synchronization, database distribution, data transformation, and the network communication optimization at the supervisory level of the communication network are discussed. At the control level, based on the specificity of communication lines for electrified railway, a structure of two layer ring telecommunication network and the efficient bi directional polling scheme in software design are utilized. Then, an analysis for the scheme under normal and disturbance conditions is given. By means of the scheme, software switching over at a fault point of a channel is realized automatically.展开更多
文摘This paper presents the design of hierarchical communication network for traction power supply supervisory control and data acquisition (SCADA) system. Some key points, such as data transmission synchronization, database distribution, data transformation, and the network communication optimization at the supervisory level of the communication network are discussed. At the control level, based on the specificity of communication lines for electrified railway, a structure of two layer ring telecommunication network and the efficient bi directional polling scheme in software design are utilized. Then, an analysis for the scheme under normal and disturbance conditions is given. By means of the scheme, software switching over at a fault point of a channel is realized automatically.