Time Synchronization System Research On The Digitized Substation

In the power system, various kinds of automation devices need to have strict timesynchronization, especially in digitized substation, electronic transformer, merge unitequipment need precise time setting. At present our country electric power GPS clock system ispopular with GPS and Beidou (BD) satellite GPS clock benchmark as single GPS, single BD,double GPS, double BD and GPS/BD redundant time synchronization system. With the rapiddevelopment of digital substation, the total time synchronization system requirements are moreand more high.This paper analyzes the time synchronization system in some of the specific application oftransformer substation, considering the situation of time synchronization equipment mostlyfor the stand-alone systems or single time source in the current market, according to GPS andBeidou clock theory, combined with the power system time synchronization technologystandards, puts forward FPGA programmable logic as the core device, using GPS, the Beidouand IRIG-B as time signal sources, choose a better signal source of multimode redundant timesynchronization system.In designing this time synchronization system, firstly, determine the overall frameworkdesign, compares the different redundant technology and the advantages and disadvantages ofthe scheme, choose reasonable solution; Secondly, complete GPS, the Beidou clock functiondesign, including with a specific message content and format and design of serialcommunication module, the optimization of the data extraction, conversion module containstime zone and the second revised data processing module and display module, etc.; And thenfinish IRIG-B yards GPS clock function design, including the IRIG-B decoding module,contains the days conversion data processing module and various format message of outputmodule, etc.; Based on the state symbol of three groups clock signals and external selective,complete three clock selected based redundant switching module design, realization signal ofredundancy input multiple output signal. GPS is currently the most extensive coverage of themost developed, GPS clock module is cheap, but controlled by the United States; The Beidousystem is independent development clock by Chinese, clock precision, clock system and safetyguarantee coverage, costs are higher; the local IRIG-B is strong anti-interference abilitycompared to the wireless satellite signal, but the cost is higher. The key points of the design isparallel decoding time signals then redundant switch function design, comprehensiveconsideration of the system cost, safety and signal source independent configuration.The designof the application of FPGA improve the running speed of the system, is convenient for the expansion of the input/output interface; The VHDL language design process is from top to thebottom expansion, and detailed design each function module, simulate them and check in thedesign process gradually, to amend the design error in time, and shorten the design cycle.This design is fully considered of the security of independent research and developmentbeidou signal, GPS signals and IRIG-B widely used by many factors in power system ofsynchronization, it has a good application popularize value.