Networking Protection In The Feeding Section Zone

At present, all parallel AT mode is usually adopted in traction power supply system for high speed railway of China. The protection configured is just traditional microcomputer protection, which can only reflects impedance parameter and current parameter of the local measurement point, traction substation, AT substation and section post therefore have no information exchange. Moreover, protection configuration basically is independent. The existing protection, whose cooperative relationship is realized by the differences between actual operation time and setting time, cannot take both selectivity and speed into consideration and make the performance optimum. Meantime, when protection trips the first time after faults occur, additional fault standard device is needed so that fault location function can be realized, and thus more equipment will be needed.According to the development of protective relaying and digital communication technology, digital communication protection technology will be the development tendency in future, through which information can be directly exchanged between protectors. Aiming at characteristics of tractive power supply system for high speed railway, with GOOSE communication technology of IEC61850 standard utilized, interconnection and information sharing between feeder protection equipment on substation, AT station and section post are realized through cooperation between intertripping and blocking, and the contradiction between selectivity and speed is solved. What is more, quick and selective tripping is realized, which shrinks the scope of forced outage and information exchange between protectors on the same feeding section is finally realized. Through simulation and comparative analysis on fault location, using transfer impedance method to realize the standardization of fault location should be a priority. Meanwhile, fault location equipment number on traction network is reduced after networking, which will be a more advanced and improved protective scheme of high speed railway traction network.In the end of the paper, the reliability of networking protection is verified through simulation on OPNET, the total time delay of either SDH network or independent optical fiber network can satisfy the requirement of network protection.