一种海上平台直流微网系统复合型短路故障检测方法

针对海上平台直流微网系统可靠性要求高、容量小、线路阻抗值小、短路故障电流上升率高、短路故障检测速度快的要求,基于方向电流法对母线短路故障检测选择性差、差分电流法覆盖范围有限的固有问题,提出电流差动法与方向电流法相结合的复合型短路故障检测方法。根据电流基本定律、各支路故障电流方向特性及变化量大小检测母线和支路发生的短路故障,并给出具体实现方法,搭建了缩小比例的实验平台,通过控制IGBT导通设置短路故障,完成了母线和支路短路故障实验。实验结果表明,母线短路故障切除时间为0.09 ms,支路短路故障切除时间为0.22 ms,检测速度优于目前直流环形微网系统短路故障检测速度,且选择性好、覆盖范围大。

A combined short-circuit fault detection method for DC microgrid system in an offshore platform

The offshore DC microgrid system has requirements of high reliability, low power capacity, low line impedance, and high fault-current rising rate for its detection. To address these issues, a kind of combined short-circuit-fault detection method is proposed, which consists of the differential current method and the directional current method. Short-circuit fault of bus and branch is detected by using the basic law of current, current direction characteristics and variation magnitude of each branch fault. The specific implementation method is given. A scaled-down experiment platform is established. By setting short-circuit fault through controlling IGBT(insulated gate bipolar transistor), experiments on short-circuit fault of bus and branch are implemented. Experimental results show that the removal time of bus short-circuit fault is 0.09 ms, and the removal time of branch short-circuit fault is 0.22 ms. The detection speed is faster than that of the current DC ring micro-grid system short-circuit fault, and it also has good selectivity and wide coverage.