配电网络单相接地故障行波频率分布在几十~几百kHz范围,应用S变换检测故障行波几十kHz的高频暂态量来实现配网故障选线。故障配网母线零模电压的S变换幅值矩阵最高频率行中幅值最大的分量所对应的时刻即为母线零模电压的突变时刻,借此标定故障电压行波首波头到达母线的时刻,并记为故障初瞬。以故障初瞬保护安装处TA检测的故障线路电流行波与健全线路的电流行波的相位相反为依据,对故障零模电流进行S变换,故障线路与健全线路零模电流S变换辐角矩阵的最高频率行的辐角在故障初瞬相差180°,借此检出故障线路。该方法从行波中相对低的高频暂态量的层面检测行波信号相位特性,降低了对行波高速采集和处理速度的要求,耐受高阻接地和抗噪能力强。大量数字仿真试验表明,选线结果准确、可靠.
In distribution network with single-phase fault, the frequency ranging of traveling wave is the from tens of kHz to hundreds of kHz. When the S-transform is implemented to determine the fault line in distribution network by detecting the tens of kHz high frequency transient component of the fault traveling wave, the moment corresponding to the maximum component in the highest frequency row of the S-transform magnitude matrix of zero modal bus voltage is the real mutation moment of zero modal bus voltage. Then the moment of the first fault traveling wave front is calibrated and recorded as the beginning moment of single-phase fault occurrence. At this moment, the phases of initial current traveling wave front in fault line and sound lines detected by TA at the protection relay device are opposite. The S transform is implemented to fault zero modal currents. The argument difference of the highest frequency row between fault line and sound line is 180° after fault, which makes fault line detectible. The proposed method detects the phase characteristics of traveling wave signal from relatively low high-frequency transient component, which can not only reduce the requirements of traveling wave acquisition and processing speed, but also enhance the capability of high resistance tolerance and anti noise ability. The simulation results demonstrate the feasibility and validity of this approach.