The Research And Design On Merging Unit (MU) Of Electronic Transducer

With the obvious improvement of transmission capacitance and rated voltage inpower system, conventional ferromagnetic transducers have several drawbacks andhave been already difficult to meet the need that network develop towards automationand digitized direction. In this case, considerable interest has been paid to theelectronic transducers, based on computer and optical technology. Electronictransducers become the revolutionary research direction. However, the interfacebetween the electronic transformers and bay device is the focus of the successfulapplication,the research and design of the merging unit is the key technology inrealizing the interface.At first, this paper introduces the principal of electronic transformers also theresearch and development in domestic and international. Then the whole designscheme of the electronic transducers are finished based on Rogowski coil and accuratecapacitor voltage divider, according to the requirement of standard IEC 60044-8 andIEC 61850, the digital output interface characteristic of electronic instrumenttransducers is introduced. analyses and research to merging unit's structural principle ,communication characteristic and function, then research into the method forimplementing the merging unit and proposes a new method using FPGA/DSP. Thisproject divides the merging unit into three different function modules: data-recoverymodule based on FPGA; data-processingmodule based on DSP; data-out modulebasedon IEC 61850-9-1.(1)Data-recovery module,its functions is adjacent to the data-sampling systemfor the transmission of simultaneous switching signals, and receive the correctinformation from the high-pressure side of the transmission of data. These sampledvalues can be ordered correctly via FPGA before they are transmitted todata-processingmodule.(2)Data-processing module, its functions is using DSP processor to designdigital filter for the receiving signals, work out the root mean square values and phaseangle, then the phase compensation technique is applied to modify the signals, at lastexport the combining frame data. to data-output module.(3)Data-output module, its functions is transmitting combining frame data toEthernet controller, then send the data to the protective device.