基于耦合电感的直流故障限流器

DC fault current limiter based on coupled inductor

柔性直流电网存在故障电流上升速度快、幅值高,感性元件储存能量大等问题,这造成故障电流难以分断,并且使得直流断路器的耗能支路承受巨大压力。为了限制故障电流峰值并且降低直流断路器耗能压力,提出一种基于耦合电感的直流故障限流器。当发生短路故障时,该故障限流器利用电感耦合特性等效投入电阻与电容组成的限流支路,以实现无延时的故障限流;当直流断路器分断故障电流时,该故障限流器利用耗能电阻耗散耦合电感储存的能量,从而分担直流断路器耗能压力,以达到降低避雷器容量需求、加快故障电流分断速度的目的。大量电磁暂态仿真结果表明,所提故障限流器具有良好的限流效果,能极大降低直流断路器的耗能压力。且该故障限流器制造成本低,易于实现。

The flexible DC grid has the problems such as the rapid rising speed and high magnitude of the fault current,and large energy storage of inductive elements,which makes it difficult to interrupt the fault current and puts the energy dissipation branch of DC circuit breaker(DCCB)under enormous pressure.To limit the peak value of fault current and reduce the energy dissipation pressure of DCCB,a DC fault current limiter(FCL)based on coupled inductor is proposed.After a short circuit fault occurs,the FCL uses the inductive coupling characteristic to be equivalent to insert a current-limiting branch composed of resis⁃tor and capacitor to suppress the fault current without time delay.When the DCCB interrupts the fault cur⁃rent,the FCL utilizes the energy dissipation resistor to absorb the energy stored in the coupled inductor,there by sharing the energy consumption pressure of DCCB,so as to reduce the arrester capacity demand and accelerate the fault current interruption speed.Extensive electromagnetic transient simulative results show that the proposed FCL has good current limiting performance,can greatly reduce the energy dissipa⁃tion pressure of the DCCB.And the FCL has low manufacture cost and is easy to be implemented.