Simulation Of Magnetic Field Distribution In A Self-recovery Fault Current Limiter With Two Liquids

At present, the executing unit of the traditional liquid fault current limiter usually forms as a single liquid, it is extremely severe to meet the demands of shape deformed and up to the process requirements, and only a little of liquid metals could be worked under this circumstance. In this study, there are three new liquid and self-recovery fault current limiter to be designed. These limiters consist of the executing unit in main part and generating means of magnetic field in other parts. A packaging shell and fixed electrodes inside the executing unit, and the generating means of magnetic field can be shaped as three different patterns of electromagnet. Conductive fluid and magnetic fluid could be injected into the executing unit, which the conductive fluid connects with the main circuits from the fixed electrode. Base on the diversification between density and magnetic performance, these two fluids will be deformed at the time when they pass through the magnetic field, thereby the resistance of the conductive fluid will be altered at main return circuit, and even the entire conductive circuit could be cut off. The performance of the fault current limiters studied in this paper is to be related with the types of magnet and the distribution of the magnetic field, as a result, the study on the distribution of different magnetic fields of fluids in executing unit seems to be very important.First of all, it is mainly introduced the current status of the research and development of the fault current limiter and the technology of liquid metal current limiter in this paper. Secondly, we set a numerical simulation as an example by ANSYS software and calculated. After sharp compare with the simulation results and analytical results, we concluded a same result. It was testified the correctness about the simulation method of magnetic field in ANSYS. Thirdly, by means of the same method to simulate the magnetic field of column-shaped fault current limiter, we obtained the distribution of both magnetic vector and isoline cloud, and also we researched the distribution of magnetic field on different section under the circumstance of different conditions in executing unit, for which we alerted the amount of ampere-turn of coil, the position we placed the electromagnet, the size of the fluid and the position of magnetic fluid and conductive fluid via transposal. The result shows:In the area of liquid, the intensity of magnetic induction is mainly shown as Bz; The intensity of magnetic induction of the region of fluid is being strengthened constantly with ampere-turn increasing; Compared the position of three kinds of electromagnets, distribution of the magnetic field is optimum when the distance is3cm between the center line of executing unit and the center line of electromagnet. With the decrease of volume of two layer fluids, the magnetic field distribution of fluid region reduced gradually, and the magnetic field gradient changed slowly; When exchanging the position of two fluids, we obtained that it’s unfavorable to the fluid out of shape in this distribution of the magnetic field. Finally, we analyzed the distribution of the magnetic field of C-shaped and U-shaped fault current limiter. We got the different distribution of magnetic field. The magnetic field of C-shaped fault current limiter shows that:the magnetic field of middle position of each fluid region is the largest respectively. Due to the existence of two magnetism gathering head of electromagnet, it is unfavorable to deformation of fluid in this distribution; For U-shaped fault current limiter, the distribution of the magnetic field in the executing device indicates that the magnetic field of middle position is the most powerful in magnetic fluid region, it is favorable to deformation of fluid in this distribution. Comparing with the magnetic field distribution of three different kinds fault current limiter, We can be drawn the fault current limiter of U-shaped is the best facility used in limiting current and breaking circuit, effect of the column-shaped fault current limiter is the second and effect of U-shaped fault current limiter is the worst.In this paper, based on ANSYS software and by means of the Finite Element Method, we simulated the magnetic field values of the three new liquid and self-recovery fault current limiter, which made the magnetic to be visual status. By means of simulation and calculation by ANSYS, we made the invisible magnetic field to be visual, it will be great helpful for further optimization of the model structure by CAD, and also the research of the new liquid and self-recovery fault current limiter will be highly promoted.