Research On Fault Current Limiter Based On Ge₂Sb₂Te₅

In recent years,the installed capacity of China’s power system is gradually increasing,and various types of power grids are gradually interconnected,which makes the peak current of short-circuit fault in power system increasing.Therefore,it is more and more urgent to reduce the impact of short-circuit current on power system and limit excessive short-circuit current.At present,all kinds of fault current limiters are limited by material characteristics,working environment,cost and other factors.Based on the characteristics of fault current limiter and the characteristics of phase change material Ge2Sb2Te5,a fault current limiter based on Ge2Sb2Te5 is designed,which provides a new solution for short-circuit current control of power systems.The main research contents are as follows:(1)The basic working principle of the fault current limiter based on Ge2Sb2Te5 is studied.The working state of the fault current limiter when the circuit is normal or short circuit fault occurs is analyzed in detail.The theoretical calculation method of the structural parameters of the new fault current limiter is given;(2)A three-phase power grid model is established based on MATLAB,and the correctness of the model is verified by the comparison of theoretical calculation and simulation results.Taking the variable resistance characteristics of Ge2Sb2Te5 material as an example,the current and voltage waveforms before and after insertion are compared and analyzed.It is found that the current limiting coefficient of fault current limiter based on Ge2Sb2Te5 can reach more than 0.7;(3)Ge2Sb2Te5 thin films were prepared by magnetron sputtering technology.The influence of magnetron sputtering parameters on the growth rate of Ge2Sb2Te5 thin films was analyzed,and the appropriate magnetron sputtering parameters were summarized.The conclusion provides a reference for the development of fault current limiter;(4)The prototype of fault current limiter based on Ge2Sb2Te5 is prepared and tested.The resistance value of fault current limiter can change 20 times,which indicates that the fault current limiter based on Ge2Sb2Te5 can effectively limit the short-circuit fault current.