针对以往双端数据不同步的测距算法中存在的伪根判断、收敛性、计算量大等问题，提出了一种快速精确的双端测距算法。该算法采用分布参数模型，通过分析线电压沿线分布变化规律，得到了线电压沿线变化周期公式，并得出了在实际长度线路上，线电压幅值沿线分布曲线最多由2条单调方向不同的曲线段组成的结论。利用此结论，采用斜率逼近的二分区间法确定曲线单调方向改变点，并以这些点为界将两端线电压曲线划分为多个求解区间，而后采用线段相交原理确定根区间。采用二分区间求根法或弦截求根法确定故障点。最后以故障处线电压幅值最低原理，给出了伪根判断算法。仿真实验结果表明，该算法克服了以往算法的不足，程序实现简单，计算速度快、精度高。

For the problems, such as false root judgment, astringency, too much computation amount and so on, existing in current algorithms of unsynchronized two-terminal fault location, a fast and accurate algorithm of fault location in HV transmission line is put forward. The algorithm is based on the distributed parameters model; the periodic formula of line voltage along HV transmission line is gotten by analyzing the change of line voltage along HV transmission line and the conclusion is drew that the line voltage curve along HV transmission line is composed of two different monotonous direction curve segments in the actual length line at most. With this conclusion, the changing point of curve monotonous direction is obtained by bisection method of slope approaching and two-terminal voltage curve is divided into several sections by these points. Adopting the principle of line segment intersection, the root section is determined. The roots are extracted in the root sections by method of bisection or secant. Finally, the false root judgment algorithm is proposed according to the principle that the absolute line voltage is the lowest value in fault location. The simulation result of ATP shows that, the algorithm overcomes deficiency of former one and the procedure is implemented simply, fast and accurately.

霍英东高等院校青年基金项目(101060)；四川省杰出青年基金项目(07JQ0075)。