基于VMD与广义S变换的HVDC线路故障定位

针对高压直流输电线路故障定位中存在的输电线路长、故障概率大、测距精度不高以及故障波形含有噪声等问题,提出了VMD分解与广义S变换结合的高压直流输电线路故障测距算法。首先通过变分模态分解(Variational Model Decomposition,VMD)对含噪声的行波信号进行VMD分解,滤去噪声并获得最优模态分量。然后采用广义S变换(Generalized S-transform,GST)计算最优模态分量,生成高时间分辨率S矩阵。并选取S矩阵中的高频分量,识别该频率分量的波形突变点,从而获取故障初始行波到达时刻。最后通过测距公式获得故障距离。PSCAD/EMTDC仿真表明,所提方法受过渡电阻影响很小,不同故障距离的测距精度很高。经过现场故障行波数据的验证,可以实现在线路范围内快速准确的故障定位。

HVDC line fault location based on VMD and generalized S-transform

Aiming at the problems existing in fault location of HVDC transmission line, such as long transmission line, high fault probability, low fault location accuracy and noise in fault waveform, a fault location algorithm for HVDC transmission line based on VMD decomposition and generalized S transform is proposed. Firstly, the traveling wave signal with noise is decomposed by Variational Model Decomposition (VMD), and the noise is filtered to obtain the optimal modal component. Then, the Generalized S-Transform (GST) is used to calculate the optimal modal component, and generate the S-matrix with high temporal resolution. And then the high frequency component in the S-matrix is selected, the waveform mutation point of the frequency component is identified, thus, the arrival time of the initial traveling wave of the fault can be obtained. Finally, the fault distance is obtained by the formula of fault location. PSCAD/EMTDC simulation results show that the proposed method is less affected by the transition resistance and has high accuracy in fault location with different fault distances. Through the verification of field fault traveling wave data, fast and accurate fault location can be achieved in the line range. This work is supported by Key Laboratory Project of Liaoning Province (No. LJZS003).