南方能源建设 (May 2024)
Optimization of Electromagnetic Field Distribution of 120 kA Pulse Inductor in Oscillation Discharge Circuit
Abstract
[Introduction] Pulse inductor is an important component of the oscillation discharge circuit in the quench protection system. In the oscillating discharge circuit, the pulse inductor and charging capacitor are used to oscillate and generate high pulse currents, causing the current flowing through the vacuum circuit breaker to reverse and create an artificial zero-crossing point, thus completing the switch breaking. However, under the condition of 120 kA current, due to the action of the electromagnetic force, the connecting bar below the pulse inductor will deform, causing equipment damage and greatly reducing the reliability of the auxiliary oscillation zero-crossing circuit. Therefore, it is necessary to conduct electromagnetic field analysis on the 120 kA pulse inductor and optimize the electromagnetic field distribution around it. [Method] Firstly, the commutation process of the auxiliary oscillation zero-crossing circuit was analyzed to establish a three-dimensional model of the pulse inductor, and the concept of magnetic field shielding percentage was introduced. Secondly, the influence of shielding plates with different materials and shapes on electromagnetic field distributions was calculated by using finite element simulation. Then the influence of different materials and shapes on shielding percentage was analyzed, and eddy current losses under different shapes were calculated. Finally, the deformation degree of the connecting bar under different shielding structures was calculated in the structural module. [Result] The results show that the use of different materials or structures in the shielding plates influences the magnetic induction intensity and electromagnetic force received by the connecting bar. [Conclusion] The circular aluminum shielding plate has a better optimization effect for the electromagnetic field distribution. This method also lays a foundation for the electromagnetic shield design of pulse inductors.
Keywords
