The Research Of Electronic Current Transformer And Its Communication Interface

The development of Power System so far has faced a series of new requirements and tasks, such as the realization of high accuracy and high reliability in fault detection and relay protection, the construction of reliable grid including renewable energy power, and the fully sharing of substation information and resources. Smart Grid has been proposed to achieve all above functions effectively. Digital substation building is an important part of the implementation of Smart Grid. At the same time the Electronic Current Transformer and its interface facility--Merging Unit which play key role in digital substation will have an extensive application prospect.This paper first analyzes the significance of researching ECT and its digital interface MU under the vigorously development of Smart Grid both at home and abroad, and then the basic theory about ECT and MU is described after analyzing the standards of IEC60044-8 and IEC61850. This paper just focused on the active electronic current transformer which uses the Rogowski coil as its sensor. The hardware design based on MSP430F2419 is discussed. In order to realize the functions of MU, a design based on AT91SAM9261 and FPGA is proposed, in which choose DM9000 to implement the Ethernet Communication function. The software design adopts the IDE of IAR SYSTEM including MSP430F2419 platform software design and AT91SAM9261 platform software design. In the later part the design of the BootLoader which according to the functions of MU and the software realization of reading and sending data are mainly discussed. To improve the transmission accuracy between the high voltage side and the MU CRC check is used, and the theory of CRC check and software realization are introduced in this paper.At last, a series of experiments (including the check of the Ratio error and the Phase error) has been conducted to test the performance of the design in this paper. And the results proved that this system fully meets the accuracy requirements.