Current system architecture of digital substation is analyzed and a software and hardware design of digital measurement and control unit based on IEC61850 is put forward. The hardware is composed of a few functional boards on CAN bus. The digital AC sampling and control board applies MPC8247 and TMS320F2812 as its hardware platform. MPC8247 receives AC data from Ethernet and TMS320F2812 performs re-sampling and calculation. The key technologies,such as synchronization and so on, are investigated. A re-sampling method using Lagrange interpolation is proposed,which requires real-time,continuality,accuracy and frequency-tracking to ensure the proper switching operation. Result indicates that,the measurement precision meets the requirement of GB/T13729 and the switching operation is correct and reliable. The unit is used in a 500 kV substation.%介绍了当前数字化变电站系统架构,提出了一种基于IEC61850协议的数字化测控装置的软硬件设计方案.装置硬件由可插拔的功能模件组成,模件之间通过现场总线交互信息.数字化交流量采集和控制模件采用MPC8247和TMS320F2812型DSP为硬件平台.MPC8247负责接收以太网上交流量数据,TMS320F2812对数据进行重采样和计算.对同期合闸等关键技术进行了研究,提出了一种拉格朗日插值的重采样方法和注意点:重采样数据必须实时、连续、准确,而且要求频率跟踪,4点缺一不可,否则将造成合闸动作不正确.实际结果表明,交流量采集精度满足GB/T13729国家标准的要求,同期操作正确、可靠.该装置已在国内某500 kV数字化变电站中得到应用.
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