Design And Influence Factor Analysis Of Binary-Fluid Current-Limiting Circuit Breaker

Binary-fluid current-limiting circuit breaker takes advantage of conductive and magnetic fluid to avoid solid contacts and it can perfectly address the problems such as electrode erosion and arcing in circuit opening. With the millisecond-speed response time, this device is able to protect the electric equipment effectively and it can recover automatically after the fault current was cut off, therefore the device has a good application prospect. This paper designed the main parameters of a binary-fluid current-limiting circuit breaker device which can be working under 630A, then conducted temperature test and breaking test to verify the feasibility of the design. In order to provide references to optimize design of the decive, this paper realised the numeiracal simulation of the temperature field, electromagneitc field and fluid field of the circuit breaker by using ANSYS and CFX software, and then analyzed effects of different parameters on temperature and motion of the fluids by numerical simulation method. The main conclusions are as follows:(1) Temperature test and breaking test have verified the feasibility of product design of the binary-fluid current-limiting circuit breaker. That is, the device can working steadily under the designed rated current and it can cut off the circuit effectivily with a millisecond-speed response time.(2) By analyzing the temperature field, electromagnetic field and fluid field of the circuit breaker using ANSYS and CFX software, it was found that the magnetization force on the magnetic fluid plays the dominant role to the motion of the fluids. The numerical simulational results are cionsisitent with the experimental results, which verifies the accuracy of the numerical simulation.(3) By analyzing the effects of different parameters on the temperature and motion of the fluid, it was found that:with the increase of the rated current, the temperature increases and with the breaking current increasing, the Lorentz force as well as the magnetization force increase, even the Lorents force can exceed the magnetization force and play the main role in controlling the motion of fluids, which is not conductive to the circuit breaking. The temperature can decrease with the increase of the height of the conductive fluid, while the magnetization force decrease as well, which will make the circuit more difficult to cut off. The height of the magnetic fluid has little effect on the distribution of the Lorentz force and magnetization force. The stronger the magnetic field, the stronger the magnetization force, which will make the circuit more easier to cut off. When the two kinds of fluids fill the container, the more easier to cut off the circuit, therefore, it is better to design the binary-fluid current-limiting circuit breaker full of just the two fluids.