Study On Parallel Transfer Current Limiter

At present,with China’s power industry developing,the power plant installed capacity is increasing and short circuit current is growing rapidly.When the short circuit fault occurs to the output of high power generator,the maximum short circuit current value will reach more than 10 kA.The traditional circuit breaker is difficult to break such a huge short-circuit current,and before the breaking,the generator or transformer winding is likely to have been deformed or burned,resulting in huge economic losses.So researching the new short-circuit current limiter has become one of the greatest demand of power manufacturing industry.Currently,it is imperative to design a practical current limiter that can limit the short-circuit current of large capacity to meet the need of China’s market.It cannot only bring great benefits to the power industry’s power plants and substations,but also enjoys a promising market in the research for the large power supply equipment in metallurgical and chemical industry,ship building and nuclear fusion test.In this paper,a parallel transfer short-circuit current limiter is researched.When the large capacity short-circuit fault occurs,the vacuum fuse starts arcing,and the short-circuit current is quickly transferred to the parallel branch,and the short-circuit current is finally broken by the parallel branch.To ensure the feasibility of the whole structure of this current limiter,and finally successfully break the large capacity short-circuit current,this paper firstly uses the Matlab/Simulink module to establish the circuit model of parallel transferring fault short-circuit current.The parallel transfer circuit model is further modified,and the dynamic simulation process of reliable parallel transferring is obtained.Then the Ansys finite element software is used to simulate the thermoelectric coupling of the high-pressure quartz sand fuse,and the arcing time of the different structural melts is obtained.Based on the semiempirical formula,the arc model of the high pressure quartz sand fuse melt is established.The total arc voltage and the arc energy value of the different structural melts are obtained.Finally,the experiment proves that the main circuit vacuum fuse can withstand the total arc voltage of the line and achieve the recovery of vacuum dielectric strength,and the secondary breakdown can not happen,so as to ensure the final success of current breaking.By the multiple test results,it can be verified that the parallel transferring model of the large capacity short-circuit current is correct,and the strategy of limiting the large capacity short-circuit current is feasible.