Abstract:
Frequency domain reflection(FDR) is one of the effective means to locate the impedance discontinuities of cable including local defects and faults. The traditional FDR method can only be used to locate the impedance discontinuity of cable but not to obtain the impedance variation state of the impedance discontinuity. Consequently, we put forward the recovery technique of characteristic time domain waveform based on FDR, and the time domain waveform can be used to obtain the impedance variation state of the impedance discontinuity. Firstly, the location algorithm of the traditional FDR method is improved through the FFT interpolation algorithm of the Nuttall window. Then, the basic principle of recovery technique of characteristic time domain waveform based on the FDR is introduced and the details are studied. Thirdly, the simulations of impedance discontinuity of cable are performed through the cable simulation platform, and the validity of the method is confirmed. Finally, a 30 m 10 kV XLPE power cable is adopted to perform experiments by the proposed technique, and the middle joint is an impedance discontinuity. The experimental results show that the proposed technique can locate the impedance discontinuity of cable and obtain the characteristic reflectometry time domain waveform.