Fast Circuit Breaker Study For Fuse Saving

As the quality of the fuses available in the market is uneven,and yet little attention has been paid,fuses have been the weak links in the distribution network,so that is not conducive to the realization of distribution network automation,is not conducive to reconfiguration with the recloser action time.According to statistics,in the distribution network,the instantaneous failure accounted for about 80%,caused by the instantaneous failure of the fuse break can be avoided.Select the monostable permanent magnet vacuum circuit breaker as the main switch.Find relevant standards to understand the relevant standards for 10 KV circuit breakers.In order to achieve the purpose of rapid breaking,through the simulation and experimental research,adjust the parameters of the circuit breaker,and ultimately the circuit breaker opening time reduced to about 10 ms,much lower than the same voltage level of other circuit breaker time 50 ms.In the case of a smaller short-circuit current;it is not necessary to quickly break the fuse.This situation is suitable for the use of fuse ampere-second characteristic curve for inverse time break.On the basis of the existing DSP control board,the intelligent breaking software system is designed.The digital filter is designed to reduce the clutter interference,and the signal of the input voltage is judged by the size of the signal.The delay time of the short circuit current of different magnifications is obtained,and the opening signal is issued;In the event of a large degree of short-circuit current;DSP-based control system processing time is too long.Therefore,a miniature repulsion actuator is designed,which can act quickly and trigger the opening control circuit of the Monostable permanent magnet actuator under the condition of large short circuit current.So that after the short-circuit fault occurs,within 20 ms,the line can be broken.In the last,the characteristics of the fuse were simulated.After simulating the different short-circuit current,the sonic characteristic curve of K-type 15 A fuse is drawn.In the case of considering the axial tensile stress of the melt,the coupling analysis of the electric,thermal and structural fields is carried out,and the influence of the different axial tensile stress on the arc time is obtained.The circuit breaker designed in this paper is connected with the fuse in series.When the fault occurs,firstly,the circuit breaker is broken.Then distinguish instantaneous and permanent failure by a reclosing,which can not only reduce the fuses due to instantaneous failure caused by malfunction,to save or protect the fuse,but also can reduce the impact of instantaneous failure of power outages,improve the reliability of the distribution network,which is in line with the distribution network development trend.