Study On The Influence Of Complex Electromagnetic Environment In Switchgear On Electronic Current Transformer

In recent years,the Electronic Current Transformer(ECT)based on Rogowski coil in the medium voltage distribution network has been vigorously promoted.But in the actual operation,measurement exceed the standard error has occurred.ECT is typically applied in the switchgear.In order to ensure the accuracy and reliability of the operation of the Rogowski coil ECT in the switchgear,it is necessary to carry out the study for the influence of the complex electromagnetic environment on the Rogowski coil ECT's error.In this paper,the main Rogowski coil ECT metering error in the switchgear is the result of the magnetic field and the electric field according to the actual operation in the switchgear and the study of the Rogowski coil ECT's error characteristics at home and abroad.Firstly,the influence of the measured current magnetic field offset,the proximate phase magnetic field and the switchgear on the Rogowski coil ECT error are analyzed theoretically,and their regulars are analyzed.At the same time,the influence of the coupling effect of high voltage electric field on the Rogowski coil is analyzed.Secondly,use MATLAB numerical simulation and ANSYS finite element simulation method to verify the theoretical analysis,and the extent of the expected affect is calculated by simulation.The main factors that affect the magnetic field of the Rogowski coil ECT by the switchgear are the local magnetic field distortion caused by magnetic field of proximate phase and bus bar's bending.In addition,the voltage of the high voltage electric field coupled in the Rogowski coil will also lead to ECT error increases.Simulation experiments were designed and carried out with further simulation,which get the actual results of the Rogowski coil ECT affected by the magnetic field and the electric field in the switchgear.Theoretical analysis and practical show that in the switchgear of the complex electromagnetic environment,Rogowski coil ECT without electromagnetic shielding can't satisfy the requirement of measurement,only by adding electromagnetic shielding to ensure that the Rogowski coil ECT meet the accuracy requirements of 0.2.In this study,a magnetic shielding structure is selected and verified by calculation and simulation.The results show that the designed magnetic shielding structure can ensure that the less affected by the magnetic field of Rogowski coil ECT in the switchgear,which meet the accuracy requirements of 0.2.