Study On Electrical Transformer Calibrator

With the increase of the capacity and voltage grade in Power system, the traditional electromagnetic transformer showed plenty of deficiencies. Moreover, the traditional transformer output can not be directly connected to microcomputer-based measurement and protection device, so it is unable to meet the needs of future digital substation. With the use of photonics technology and optical fiber communication technology, the electronic transformer has overcome the shortcomings which exist in the traditional transformer, so electronic transformer will lead the technology development of transformer. However, the development of electronic transformer will inevitably bring about the development of calibration error, so speeding up the research on electronic transformer calibrator will be of great significance. In this paper, under the research on the calibrating methods in analog output and digital output of electronic transformer, we design and develop an electronic transformer calibrator.First of all, the article briefly introduced calibrating methods on traditional transformer, compared the difference between electronic transformer and traditional transformer. The article focuses on the calibrating methods in analog output and digital output of electronic transformer. Comparing those methods, we choose difference method for the use of analog output and direct method for the use of digital output.Secondly, we designed the electronic transformer calibrator. The electronic transformer calibrator was composed of Industrial Personal Computer, Card for Data Acquisition and Difference Detection Circuit. This article focuses on designing of hardware with Difference Detection Circuit, this Circuit is based on the Analog-to-Digital Converter of MAX125 and the Single-chip .With the use of Phase-locked loop technology, the entire cycle of signal sampling is become possible. In order to select the Gain for input signal as our wish, Programmable Gain Amplifier was chosen. In software, this paper showed the flow chart of the relevant control procedures.Finally, we test the Check-channel in analog input of the electronic transformer calibrator. The test results show that the channel meets the calibrating requirements.