放射直流微电网短路故障保护策略

考虑直流微电网故障电流突增、电压突降特性,提出基于支路两端导纳差值导数的保护方法.通过检测支路两端的电流和电压,计算支路两端导纳的差值并求导,以支路导纳差值的导数作为故障判据,该判据充分利用了故障线路电压和电流参量,提高了保护灵敏度,且导纳差值的导数在故障发生初始阶段最大,可快速与动作阈值比较,判断故障发生与否,减少了...

Protection strategy of short circuit fault in radial DC microgrid

Considering the characteristics of fault current surge and voltage drop of DC microgrid, a protection method based on derivative of admittance deference between two ends of the branch is proposed. By detecting the current and voltage of two ends of the branch, the admittance difference between two ends of the branch is calculated and its derivative is obtained. Taking the derivative of admittance difference as the fault criterion, the voltage and current parameters of the fault line are fully used to improve the sensitivity of the protection. The derivative of admittance difference is the largest at the initial phase of the fault, which can be quickly compared with the setting threshold to judge whether the fault occurs or not, thus reducing the time of waiting for the current or voltage to change to the threshold during fault detection. The proposed method is compared with the over current protection and under voltage protection. The results show that the proposed method has better performance in the aspects of speed, sensitivity and protection range.