基于短路电流小半波特征的短路故障快速检测方法

为使超高压输电线路上的限流器在短路早期快速投入，短路故障快速检测方法的研究至关重要。首先分析了短路电流暂态特征随故障初相角等因素的变化规律，发现部分故障初相角短路工况下电流呈现小半波特征的现象，此时传统检测方法难以满足速动性的要求。然后提出了一种基于短路电流小半波特征的检测判据，利用电流瞬时值或变化率的零点间隔作为检测量，与传统检测判据配合，实现了任意故障初相角下的短路快速检测，并保证了在负荷投切等干扰工况下的可靠性。最后通过离线仿真、现场短路试验验证了该方法的有效性。结果表明所提方法能在2.9 ms内辨识出短路故障。

Fast short-circuit fault detection method based on a small half-wave feature

To put the fault current limiter on a UHV transmission line into operation quickly in the early stage of a fault, research is conducted on a fast short-circuit fault detection method. First, the transient characteristics of the short-circuit current with initial phase angle and other factors are analyzed, and it is found that the early short-circuit current at some initial phase angle presents small half-wave characteristics. The traditional detection method finds it difficult to meet the speed requirements for action. Then, a detection criterion based on the small half-wave characteristic of the short-circuit current is proposed. This uses the zero-crossing time interval of the instantaneous value or of the rate of change to quickly identify short-circuit faults. The fast detection of a short-circuit fault at any fault initial phase angle can be realized by combining with the traditional criterion, and the reliability under load switching and other interference conditions is guaranteed. Finally, the effectiveness of the fault detection method is verified by offline simulation tests and a field short circuit test. The test results indicate that the detection time of the proposed method can be within 2.9 ms.This work is supported by the National Key Research and Development Program of China (No. 2018YFB0904300).