Research And Design Of The DC Leakage Current Transformer

The DC power supply in electric power system is a complex and deep degree system.It is significant to measure the DC leakage current to ensure the safety operation of the power system.Magnetic modulation transformer is widely used to measure the DC leakage current in the system,but the traditional method of the magnetic modulation transformer is not very suitable for the measurement of DC leakage current.At present,there are few researches on the measurement algorithm of the DC leakage current and the effect of the temperature on the transformer.In this paper,the traditional algorithm is improved to measure the DC leakage current,and design a transformer system using the improved algorithm.Aiming at the c ore of the model for better understanding of the influence of temperature on the transformer.The compensation method is proposed for this effect.The development of this project can make up for the existing research,and improve current measurement level.In this research,the measurement method is proposed to measure the DC leakage current and the relevant research results to analyze the research results related to this topic at home and abroad and summarize the current methods of measuring DC leakage current..The design of the DC low current transformer based on FPGA is divided into two parts: hardware design and software design.The hardware design provides a platform for the software design,which is based on the differential algorithm for the DC leakage current,and uses the double coil to measure,which can improve the accuracy of the system.And FPGA has a large number of IO resources,for the future after the expansion of the multi-channel transformer.The software part uses the FPGA kernel development,it has two kinds of output modes,they are serial port output and DA voltage output,which makes the transformer output more directly.The experimental results show that the measurement accuracy of the proposed transformer can fit the requirements of the power grid.Finally,in order to solve the problem caused by temperature,the temperature field of the core model by ANSYS is established,and the relationship between the temperature and the magnetic permeability is observed under the same conditions.After it finished,according to the different current,relationship between the measured current and the magnetic core is observed.Temperature compensation scheme is proposed corresponding to these two kinds of effects on the permeability of core source.