Single From Off Switch Bridge Type Fault Current Limiter Topology And Control Strategy

Along with the power system scale and capacity continues to expand, power system short circuit capacity is increasing, which buries a serious hidden trouble to the system security, stability and reliable operation. Original current limiting technology has been gradually revealed limitions, therefore, a novel current limiting scheme or current limiting technology research has become an urgent task.Based on the simple introduction of several typical fault current limiter, focusing on the study of power electronic bridge type fault current limiter, compared the bridge type fault current limiter based on half-controlled switch with the one on the basis of self-turn-off device, emphasized on the research based on the self-turn-off device fault current limiter, put forward a novel controllable resistor type fault current limiter based on a single controlled switch.The main circuit topology of the single-phase system and three-phase ungrounded system is designed. By the controllability of conduction and turn-off of self-turn-off device, in view of the different states (the normal state and fault state), realize constant value resistance adjustable in the circuit, making that dc side inductance can also participate in the current limit, reduce the volume of the bypass inductances effectively, reduce the cost significantly and save space. On this basis, according to the working characteristics of the power components, optimize and design the parameters of power device and the structure of the dc side and bypass inductances in the fault current limiter. In addition, make a design on the control strategy of solid state bridge type fault current limiter in detail, including monitoring methods to the short circuit fault in all the short circuit modes, feedback of the signals, generation of the pulse and drive of the turn-off device and isolation of main circuit. In order to validate the effectiveness and reliability of the new topology structure and the control strategy, the single-phase system with one phase grounding fault and three-phase ungrounding system with two phases fault and three phases fault are simulated by Psim simulation software. Based on this, the corresponding hardware is designed and a fault current limiter experimental platform for single-phase system is set up, further verified the feasibility and practicability of the topological structure.