The Theory And Experiment Of The Saturated Core Fault Current Limiter With Permanent Modules

With the development of power system,the capacity of generator,transformer substation and electrical load is larger and larger.Meanwhile,the interconnection among power grids is a trend.All the factors contribute to a larger and larger fault current.In some places,the fault current even exceeds the switch capacity of a breaker.Therefore,the need to limit the fault current is very urgent.In this paper,a novel energy-efficient saturated-core fault current limiter(FC L)with permanent magnet(PM)modules is proposed.This structure solves the three problems of the open core FC L.Firstly,comparing with the origina l FC L strucyure,the novel FC L meets the same performance criteria but can reduce a lot of DC energy consumption.Secondly,the magnetic flux density reduction in steel cores near the end of the cores is much less than that in origina l st ructure.It means that we can save a lot of core material and make the volume of FC L smaller.Thirdly,the producing and maintaining cost of the FCL is much less than the original structure.In this paper,a real model of the novel FC L structure is produced and related experiments are done on the model.The experiment results show that 67.6% fault current peak and 63.1% steady-state fault current amplitude can be reduced by the FCL.Finally,to know the operationg point of the cores,a n equivalent magnetic circuit model of the saturated-core FC L with permanent magnet is given and the model shows a great accuracy verified by finite element simulation.Meanwhile,An equivalent electric circuit model of the saturated-core FC L with permanent magnet is given and the model shows a great accuracy verified by experiment.The equivalent electric model can be used to caculate the fault current.