10kV Current/Voltage Combined Transducer

According to the actuality of the present research on electric transducers, it is introduced that a new design scheme of electronic current and voltage combined transducer, which is based on the Rogowski coils and accurate resistor voltage divider. This kind of transducer will be used in 10 kV switching box. It overcomes the drawbacks that conventional transducers have, and it has many good characteristic such as small volume, good linearity, wide frequency bandwidth, no magnetic saturation and etc. It can do measurement and protection at the same time. Besides that, it can communicate with the computer through the communicating interface and send parameters of the power system and accepting the instruction.In this paper, the principle how the transducer measures the current and the voltage of power system is discussed. A new kind of Rogowski coils, which is made of PCB, is brought forward. The way to make PCB Rogowski coils is also discussed in the paper. The linearity of PCB Rogowski coils has been tested. It could be considered that the PCB Rogowski coils is perfect as a current transducer, according to the simulation of the coils' magnitude vs frequency characteristic and phase vs frequency characteristic. In addition, the factors that impact the precision of the divider have been analyzed and overcome by the design of divider's cover.In order to test the transducers effect, a digital wattmeter system is designed and made. MSP430 MCU, made by TI corporation, is used for sampling, processing and communicating. Moreover, the software of MCU and the structure of combined transducer are also designed. The electronic combined transducer works well and has good precision, through the analysis of the experimental results.