| IRIG-B has been widely used for synchronization in traction substations at the moment.The system is easy to build with high accuracy,while optical fiber link replacing cable lines can shield the outside electromagnetic interference which improves the capacity of anti-jamming in the system.However,the synchronization network based on IRIG-B is separate from the communication network,making it difficult to detect errors since the system needs more lines.The synchronization system is definitely the basis of protection,measurement,and control of the traction substation,which,with the digital transformation of traditional substation and new substations to be put into use,concerns the experts.The IEEE 1588 synchronization system has been considered as a better way of synchronizing clocks in recent years,which,on the contrary,transfers clock signals through the Ethernet and shares one network with sampled values as well as switch signals.In this paper,several different measures of synchronization was analyzed on both technical details and application occasions,including PPS pulse,IRIG-B,NTP/SNTP and IEEE 1588 protocol.To meet the requirement of self-adaption,strategies were introduced of synchronization under the circumstances of abnormal GPS signal,so was the comparison of advantages and disadvantages between them.In addition,networking mode was also discussed in this paper due to common network resources sharing of IEEE 1588 system above.An IEEE 1588 synchronization system was involved in this paper,in which the clock of a PTP node will be built using a dual-core device ADSP BF609 as its main chip and a network card DP83640 supported for IEEE 1588 protocol.Under the circumstances of abnormal GPS signal,the PTP port state will be PASSIVE,SLAVE or MASTER on the Best Master Clock(BMC)algorithm.In the end,this system will go on with a real test.Its result shows characteristics of self-adaption on network topology changing,high level of conformance to requirements on information sharing,which serves as a valuable reference for real project applications. |
