The Research Of New Saturated Iron Core Superconducting Current Limiter

The expansion of the scale of power system and the improvement of the degreeof the interconnection recent years make short-circuit current increasing rapidlywhich has become a problem that a power system design and operation has to face.With the trend of the electricity market, higher requirements of transmission capacityand reliability of high-voltage lines are put forward. The traditional current limitingdevice can not meet the requirements of the development of the electric power systembecause of its limitations.Superconducting Fault Current Limiter which sets detection, trigger and limitflow in one and has an automatic recovery feature, shows very low impedance on thenormal working of the power system and has almost no effect on the system. SCFCLoutputs high impedance when the short-circuit fault occurs so as to limit theshort-circuit current. SCFCL is an ideal and promising fault current limiting means. Inthis paper, theory and simulation of the saturated core type SCFCL has been mainlyresearched, a new saturated core SCFCL topological structure has been proposed andthe simulation research of this kind of structure has been carried on. The main work isas follows:First, this paper describes the significance of limiting the short-circuit currentand the development and status quo of the SCFCL, introduces in detail the workingprinciple and the basic structure of saturated iron core SCFCL and studies the selec-tion of core material and impact of the performance of the current limiter. This articleproposes design method according to the type of saturated iron core superconductingcurrent limiter working characteristic and the physical parameters, obtains dynamicequation which is used to simulate and carries out simulation and study based onMATLAB.Secondly, this paper presents a new saturated core SCFCL topological structurethat it strings into the current limiting resistor in the AC winding side, quickly identi-fies based on short-circuit current and cut off DC circuit by the IGBT; It presents thesimulation model of a380V/22A saturated core SCFCL, accesses the saturated core SCFCL to the low pressure system and carries out short-circuit fault simulation whichdemonstrates the effectiveness of limiting.Finally, this article further studies the limiter’s limiting effect under differentload conditions and various short-circuit faults and the simulation results show thatthe current limiter has a very effective limiting effect. This paper studies the limitingeffect which is affected by current limiter based on the simulation results and its op-erating characteristics of the current limiter. All of the above work not only from thetheoretical and simulation results both demonstrate the feasibility and advantages ofSCFCL, but also laid the foundation for SCFCL product development.