766 / 2022-03-31 21:22:23

Simulation and Analysis of Shielding Effectiveness of Shielding Structures in the Vicinity of High-voltage Bushing Leakage Current

high-voltage bushing;,leakage current measurement,shielding effectiveness,shielding structure,simulation and analysis

      Leakage current is an indispensable basic parameter for sensing the insulation state of high-voltage bushing. To improve the reliability of sensing the insulation state of high-voltage bushing, it is first necessary to ensure that the measurement results of leakage current are accurate, stable and reliable. However, the leakage current measurement belongs to the precision measurement category, it is at the μA level or mA level, which is easily disturbed by the external environment. The purpose of this paper is to study the shielding effectiveness of the shielding structure, thereby providing zero magnetic space for the leakage current measuring element.

     In order to accurately calculate the magnetic field and provide a theoretical basis for the magnetic field shielding technology, three-dimensional electromagnetic calculation method is adopted in this paper. The calculation results are verified by the experimental method. The Hall magnetic field detector was used in the experimental verification.

     The scheme  with 90°opening of the end face, the thickness of the magnetic shield is 3mm, and when the super permalloy material is used, the magnetic field penetration is the smallest, and the magnetic shielding effect is the best, which is the most suitable scheme. The position of the opening of the measuring element leads needs to take into account the direction of rotation of the magnetic field.