High accuracy sequence of event system based on GPS

Abstract

In order to meet the resolution requirement of hundreds of microseconds,microsecond global clock synchronization must be achieved in Sequence of Event(SOE) system.By means of assessing the existing clock synchronization methods and analyzing the cause of the error in the clock synchronization process,a new method based on the combination of improved Network Time Protocol(NTP) server synchronization and 1PPS synchronization was proposed.That is: advanced NTP server was used to eliminate the clock error between the control stations,"cross-second" phenomenon was avoided in this situation;1 PPS was used to synchronize the millisecond counters in order to eliminate the crystal accumulated error of Field Programmable Gate Array(FPGA).This method is simple,precise and stable.The resolution of SOE system by using this technique can be up to 0.5 ms,and it has been applied to the turbine protection system in a power plant successfully.