Research And Analysis Of A New Saturated Reactor-type Fault Current Limiter

The electricity has become one of the essential energy of human society，and theemergence of large-scale power systems provide a great convenience for human usingelectricity. However，with continued investment in large-capacity generator sets andthe impact of intenretworking，the scale of the power system is constantly expanding，which makes the short-circuit current constantly improved，and it brings the presenthuge risks for system’s security，stability and reliable operation，thus limiting theshort circuit current effectively has become a problem that should be solvedurgently. Fault current limiter(FCL) has received extensive concern from the electricalworkers as an effective technology measure to limit current.This paper aims to study the topology and the current limiting principle of a newsaturated reactor-type fault current limiter，and verify the effect of limiting current bysimulation. The main research work of this paper includes the following aspects：Firstly，the paper introduces the basic principles and the development status ofvarious types of FCL，and focuses on analyzing the limiting principle of saturatedreactor-type fault current limiter. On this basis，the paper studies a new saturatedreactor-type fault current limiter. This FCL consists of two core components, and itselectricity of the DC control circuit is extracted from the AC circuit by voltagetransformer, and an IGBT switch is placed in the DC circuit. By the theoreticalanalysis，the paper studies the limiting principle of this new saturated reactor-typefault current limiter’ establishes a mathematical model，and focuses on analyzing thetransient process of this limiter limiting current. It accounts the limiting characteristicsof transient process in detail, and introduces the calculated methods of the restrictioncoefficient，proves the good limiting effect of this FCL in theory.Secondly，the paper carries out a simulation analysis to the new saturatedreactor-type fault current limiter. By MATLAB/SIMULINK simulation sotfware，itbuilds a system model of grid，and introduces the optimization process of the newsaturated reactor-type fault current limit’ers topology structure by the simulation analysis，carries out a single-phase system simulation analysis to the new saturatedreactor-type fault current limiter, discusses the mutual relations between the variouselectrical quantities by simulation waveforms，and draws the limiting effect of thenew FCL by analyzing the changes of the short-circuit current，contrasts to thelimiting effect of different short-circuit points，explores the affect of short-circuitpoints to the limiting effect，then carries out a three-phase system simulation analysisto the new saturated reactor-type fault current limiter，draws the present limiting effectof the FCL.Finally，the paper analyzes the impact of the FCL on the power system. It studiesthe impact of the FCL on the power system transient stability, discusses the impact onthe relay protection，and explores the new problems that the new saturatedreactor-type fault current limiter brings to the power system.