403 / 2017-04-26 11:04:27

Study of the Arc Motion Characteristics of Low-Voltage Circuit Breaker based on Magnetic Sensor Array

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会场 > Switching Phenomena in Air (Low-voltage Circuit Breakers and Relays)

Low-voltage circuit breakers are used in power distribution systems in order to provide load and line protection in overload and short circuit events. The arc pattern and its motion characteristics, are not only the cruxs to the success of breaking the electric circuit, but also of great concern for the interruption performance and electrical life of breakers. In open process, the magnetic intensity distribution around the circuit breaker changes with the arc movement. In order to find the relationship between the movement of arc plasma and the magnetic intensity distribution around circuit breaker, the experiments have been carried out with a kind of low-voltage miniature circuit breaker. The test system contains of: 1) the measuring device composed of 64 magnetic induction hall sensors located in the outer wall of the breaker to obtain the arc pattern through inversing the magnetic field data around breaker; 2) the high-speed camera for obtaining the image of the arc movement ; 3) the oscilloscope that measures the arc current and voltage variation during the open process. The schematic diagram of the experimental system is shown in figure1. Fig. 2 shows the typical experimental results, which presents a series of the images that describes the process from arc ignition, expansion to extinction and the magnetic field distribution around circuit breaker. By comparing the magnetic field distribution around circuit breaker with the image of arc at several moments, the change characteristics of magnetic field distribution around circuit breaker with the movement of arc can be obtained. The boundary between two directions magnetic field is the path of arc plasma according to the right-hand rule, which moves toward splitter plates gradually with arc moving toward splitter plates, and the strength of magnetic around circuit breaker becomes weak attributing to the decreasing arc current. The result indicates that the movement of arc plasma has an obvious influence on the magnetic field distribution around circuit breaker. The circuit breaker with ferromagnetic iron and without splitter plates also been tested in order to further study the influence of arc movement on the magnetic distribution around breaker. The experiments results under the above two conditions verify the change rule, it can also be obtained from the relationship between the arc movement and the magnetic distribution around the circuit breaker that the ferromagnetic iron has the effect of promoting the movement of the arc towards the splitter plates and speeding up the arc extinguishing, and in the absence of splitter plates, the arc is extinguished very slowly and is pulled off on the arc runner.