基于扰动注入的柔性直流配电网主动故障定位及其仿真研究

Study on fault location method and simulation for VSC-DC distribution network based on disturbance injection

直流配电网中电力电子元件耐受故障电流能力差,要求保护数毫秒切除故障,因此留给故障定位所使用的数据量有限。现有基于暂态电流单端量测的定位方法受分布式电容、噪声和过渡电阻影响较大,难以实现精确的故障定位。因此,考虑故障发生后直流断路器快速动作,在系统失电的情况下给系统串联一个LC注入装置构成衰减的振荡扰动,利用振荡频率、衰减系数与故障距离的关系,可以精确定位故障位置。仿真结果表明所提方法可行且具有一定的耐受过渡电阻、分布式电容、噪声和线路参数误差的能力。

The power electronic component in DC distribution network can’t withstand high current, which requires protection remove the fault in a few milliseconds, so the amount of data used for fault location is limited. The existing positioning method based on single ended transient current measurement can’t realize accurate fault position influenced by distributed capacitance, high fault resistance and noise. Considering that the fault has occurred, DC circuit breaker breaks off quickly, in the condition of loss of power system, it is connected in series with a LC injection device to form a decaying oscillation disturbance, and the fault location can be accurately located by using the relationship between the oscillation frequency, the attenuation coefficient and the fault distance. The simulation results show that the proposed method is feasible, with a certain ability to withstand fault resistance, distributed capacitance, noise and line parameter errors.