电子式互感器较电磁式互感器有体积小、动态范围大、无铁磁谐振、绝缘性能好等显著的优势，数字化变电站必将广泛采用电子式互感器，然而在数字化变电站实现中的关键技术问题之一就是电子互感器与变电站二次设备之间如何接口，而本文研究的合并单元就是连接电子式互感器与二次设备之间的装置，它对简化二次设备，提高系统的准确度和可靠性，实现变电站内的信息共享和系统集成具有重要的理论意义和应用价值。 本文以IEC61850标准为基础，详细分析了相关标准中对电子式互感器的数字接口元件（合并单元）所作的规定，同时对合并单元的通信特点及功能划分进行了详细的分析与研究，将合并单元合理划分为数据接收模块、数据处理模块和数据输出模块三个功能模块，在此基础上提出了本文的设计思路。 本文首先按照IEC61850标准对合并单元进行了信息建模；接着采用FPGA技术详细设计了合并单元的数据接收模块，并对合并单元的同步问题作了深入的分析与研究，采用了一种自适应的时钟同步法对采样数据进行同步处理，该方法能很好的保证数据的同步；最后设计了合并单元的数据输出模块，采用了ARM与以太网控制器组成的硬件开发平台，按照IEC61850-9-1实现了采样值的编码和快速传输，并通过实验验证了其传输数据的正确性。 软件仿真及实验结果证明本文设计的合并单元的两个功能模块都能较好地完成各自的功能，为解决合并单元同时处理多任务、通信信息流量大、通信速度高等问题提供了一种可行的实现方法。

Electronic Transformers have more advantages then electromagnetic transducer ,such as small in size, large dynamic range, without Ferroresonance, good insulation ect. It will be widely adopted in digital substation. But in the realization of digital substations, one of the key technologies question is how to interface between the electronic transformer and the second equipment, and the merging unit is the device of connecting electronic transformer and the second equipment , so researching the merging unit not only can simplify the second equipment but also can improve the accuracy and reliability of realizing the sharing of information within the substation and enhance system integration, it have great theoretical significance and application value. Based on IEC61850 standards, this paper described and researched the features and functions of merging unit－the digital interface components of electronic transformer of the relevant standards. At the same time it is reasonable divided to three function modules: data receiver module, data-processing module and data output module, which is based on the design of this paper. This paper first design the model of the merging unit according as IEC61850 standards, secondly, it use the FPGA technology design the data receiver module of merging unit. It also research in-depth the synchronization problem of merging unit, and use the method of clock synchronization to sync the sampling data of merging unit, this method can good guarantee data synchronization; Finally, it design the data output module, using ARM and Ethernet controller hardware platform, it realizes the sample data rapid and accuracy transmission according as IEC61850-9-1. Software simulation and experimental results show that the design of the two units function modules of the merging unit can better accomplish their respective functions, it also provided the realization of a viable method of merging unit to solve the same time multi-tasking, communication of information flow, high speed of merging unit.