Research Of Error Detection System For Electronic Transformer

In recent years, with the rapid development of computer, communication technology and sensor technology, the State Grid Corporation proposed the grand strategy of building the unified strong and smart grid. The original transformer substation reconstruction and the new transformer substation commissioning have been fully in the development of digital substation. As an important component of power system equipment, the electronic transformer has been widely used in smart grid construction for its high accuracy, wide dynamic range and providing the digital interface for the secondary equipment. The accuracy of electronic transformers is very important for measurement and protection equipment of power system, so calibrating its accuracy is significant.Basing on the standard IEC61850-9-2 and related materials, this paper build an error detection system of electronic transformers by the technology of FPGA and Lab VIEW. The system adopts the direct comparison method. It can be used to check the accuracy of electronic transformers under 0.2 level.Firstly, the paper introduces the working principle of electronic transformer and merging unit, gives the definition of parameters and errors about the electronic transformer. Then the paper puts forward the designing frame of detection system. In the aspect of hardware, the signal conditioning circuit and A/D conversion circuit have been designed for the acquisition and conversion of standard transformer's output data. In order to achieve communicate with the merged unit, the ethernet controller circuit also has been designed. Finally, the USB transmission control circuit is completed, which is used to transform the two channels' sampling value. In the aspect of software, the paper first introduced the standard IEC61850-9-2. According to this standard, programming and simulation for receiving and analyzing the sampling value have been completed. Then, the paper uses the VI of Lab VIEW to complete the function module design including data packets separation and extraction module, fourth order rectangular self-convolution window module, error calculation and user interface module. Finally, the paper conducted the accuracy test, referring to the error test of National High-voltage Metering Station. Test datas show that:the whole system is reasonable and feasible, the system accuracy can be up to the relevant regulatory requirements.