Application Study On The Characters Of Electronic Current Transformer

With the incessant improvement of transmission capacitance and rated voltage in power system, conventional ferromagnetic current transducers reveal several shortcomings. It has already been difficult to meet the requirement that network develop towards digitized, computerized, and automated direction. In this case, it is an inevitable trend that conventional ferromagnetic current transducers will be taken place by electronic currrent transformer. The ECT will become a hot research.Firstly,this paper briefly introduces the application situation and development trend of the domestic and foreign electronic current trans former. Then introduces the principle,structure and classification of the ECT. This paper focuses on the structure and basic principles of the ECT based on Rogowski coil,compares three different shapes and studys the anti-interference property on the magnetic field of the Rogowski coil. This paper also designs the integral part of the Rogowski coil in detail,and the simulation proves that it can well reflect the transient fault current. At the same time, we find that appropriately increasing the integral capacitance parameters of the negative feedback integrator can improve the transient response performance. We also design an improved precision integrator, only a smaller integration capacitor needed to have good transient response. In the end of this paper, we import the COMTRADE format data from the dynamic simulation to the MATLAB for waveform reproduce and analysis, implementing the exact comparison between the ECT and the traditional CT. In the situation of two-phase grounding falut at the line outlet,the traditional current transformer occurs saturation while the electronic current transformer has a good waveform. Through the effective value calculation of the two kinds of current transformer’s transient waveform.further verifies the superiority of the electronic current transformer. In addition,through the Fourier transform of the two sets of current data,we realize the precision acquisition of the phase angle difference,and then apply phase-shifting algorithm for phase compensation.The paper summarizes at last, and brings out the problems needed to be solved in the future.