Research On Precision Clock Syncchronization Technology In Microgrid Based On IEEE1588 Protocol

With depletion of traditional primary energy, solar, wind power and other clean energy have become an important research direction of energy field. Microgrid is an effective way to exert the distributed power, and it has a great social and economic significance. Due to the increasing size of the microgrid project and the large number of automation equipment using in microgrid, microgrid system structure become more complex. The stable operation of microgrid proposes new requirements on measurement devices and control devices in microgrid, especially clock synchronization. These devices need real-time sampling, monitoring, recording all kinds of power quality data at runtime, such as voltage, current, frequency and active. If there have no unified standard timing and clock, it will be difficult to meet the equal time requirement for consistency of the real-time data sampling, system stability judgment, line fault localization, fault recording, fault analysis, the sequence of events recording (SOE),etc. To solve the problems of clock synchronization in microgrid, this article made the following main research:(1) To meet the functional requirements of engineering applications of microgrid and the hardware and software capabilities need of intelligent devices, and combining the feature of microgrid system structure, we propose a time synchronization method for the microgrid system based on IEEE1588 precision clock synchronization protocol referring to several clock synchronization methods for digital intelligent substation in traditional power system.(2) Considering the feature of layered control microgrid system structure, the clock synchronization system in microgrid is divided into multiple clock domains and the diagram of microgrid PTP system structure is given in this paper. The intelligent devices in microgrid such as the intelligent gateway breaker and inverters have been redefined, these devices have been defined as Slave Clock devices in the PTP system. To meet the reliability and precise demand of microgrid timing, a Grand Master Clock device using Beidou satellite time has been added in the PTP system. IEEE 1588 protocol has requirements for hardware and software of intelligent devices, these intelligent devices need functional design under the premise of achieving their primary functions, including IEEE 1588 protocol stack implantation and acquiring hardware timestamp.(3) To measure the path delay and clock offset between the Master Clock and Slave Clock, a simple Ethernet communication verification platform has been built, including sub-microgrid system controller, Grand Master Clock, the intelligent gateway breaker and inverters. Using conventional switch device to set up the tree network, In this way, we can verify clock synchronization and improve engineering efficiency, experimental result meets the accuracy requirements for clock synchronization of IEC61850 with an average time deviation of 10 ?s. The existence of problems and shortcomings in the experiment are supplemented and it proposes an improved method. The application of Clock synchronization in microgrid was validated on 500kW demonstration platform, we add the sequence of events recording function in the intelligent gateway breaker at the PCC node of microgrid to verify this application and achieve the initial application.