The Design And Implementation Of Circuit Breaker's Operating Mechanism

Circuit breaker as an important equipment of transmission line, its performance is directly related to the safety of electrical equipment downstream. Any one circuit breaker failure may lead to huge economic losses and even loss of life. Therefore, developing a circuit breaker with good performance is very important.An ideal circuit breaker requires the closing time as short as possible and the terminal closing velocity within a certain range. In order to reduce the closing time, we should provide a large suction to the moving parts of the circuit breaker in the beginning of the closing moment, and let the moving parts accelerate quickly. In order to let the terminal closing velocity within a certain range, we should provide a large repulsion to the moving parts of the circuit breaker at the end of the closing moment, and let the moving parts decelerate quickly. Therefore, an ideal circuit breaker operating mechanism can not only accelerate but also decelerate.This paper introduces the developing history of circuit breaker and its operating mechanism, especially the developing history of electromagnetic driving and permanent magnetic keeping operating mechanism (EDPKPM), summarizes the types of EDPKOM, investigates the performance advantages of EDPKOM, and analyzes the recent research work by researchers on how to improve the performance of EDPKOM. As the performance of the typical EDPKOM is not ideal and the structure of the improved EDPKOM is complex, a new permanent magnetic driving and permanent magnetic keeping operating mechanism (PDPKOM) is proposed.Moreover, the reaction force of 10kv vacuum interrupter has been tested by MTS809 system, the magnetic field of the PDPKOM has been analyzed by Maxwell software, and then the structure was confirmed. Physical prototype of 10KV circuit breaker is made, and its mechanical testing is carried out by MTS809 system. Results of mechanical testing show that this physical prototype achieves the desired design goals.Finally, this paper analyzes three control modes of circuit breaker: Relay control, electronic control and computer control, and choose the third one to control the 10KV circuit breaker physical prototype. The control circuit is design and control strategy is given. Testing of the 10KV circuit breaker physical prototype shows that this physical prototype has good performance.