Transient Characteristic Analysis Of A Fault Current Limiter With Switch Characteristic

With the expansion of the scale of the grid and the major grid interconnection increasingly close, the level of power system short-circuit current is increasing. Huge short circuit current will not only increase the burden on the dynamic and thermal stability and hazard electrical equipment itself, but also a serious threat to the safe and stable operation of the power system, therefore, take appropriate measures to limit the level of short-circuit current become an urgent problem. Fault Current Limiter (FCL) as a new type of current limiting device, has the superior limiting performance, and it has been widespread concern at home and abroad.In this paper, the topology and principle of a fault current limiter with switch characteristic of current has been studied and analyzed, and validate its transient characteristics and current limiting effect through software simulation and model machine experiments. In this paper, the research work is as following:Firstly, introduce the classification of fault current limiter and its development status, and analyze the advantages and disadvantages of each type fault current limiter. On this basis, present a new fault current limiter with switch characteristic, through the improvement of the access to the DC side bias current acquisition of the saturable core current limiter. This fault current limiter has two cores, AC winding, DC bias winding and a rectifier circuit and its control loop. And the DC bias current is no longer supplied by the DC power directly, but through the normal load current rectifier. Through the analysis of its limiting principle, construct its mathematical model, focusing on the current limiter’s transient characteristics, and pointed out its superiority comparing with other types of limiter. Then by formula derivation, give the design principles of fault current limiter with switch characteristic, which provides strong theoretical support for the rationality of the designment.Secondly, a220V voltage level fault current limiter model is designed. Then build simulation models using MATLAB/SIMULINK simulation software to simulate and analyze its performance under short-circuit fault. Through observations of the relevant electrical quantities, and comparing with the experimental results of the model machine, verify the feasibility of this current limiter’s designment.Finally, this paper analyzes the impact of the fault current limiter on power system transient stability and distance protection.