Identification and Location of Cable Faults Based on Input Impedance Spectrum

Abstract

In order to solve the shortcomings of impulse current experimentation (ICE) and time domain reflectometry (TDR) in the diagnosis of power cable faults, a method based on input impedance spectrum is proposed for identifying and locating cable faults. First, according to the distribution parameter model of power cables, input impedance spectrum, spectrum analysis, and Kaiser window, the basic principles were explained in detail. Then, different types of cable faults (open-circuit, short-circuit, high-resistance and low-resistance faults) were modeled and analyzed. And the input impedance spectrum characteristics of normal/fault cables were obtained by simulation. Based on this, the input impedance spectra of the faulty cables were analyzed to obtain an intuitive fault location spectrum, thereby achieving high-sensitivity location of cable faults. Finally, to test the effectiveness of the method, fault simulations were carried out on the 40 m-long coaxial cable and the 1 000 m-long 10 kV cross linked polyethylene (XLPE) power cable in the laboratory. The simulation and test results indicate that the method has a good recognition effect for the open-circuit fault and fault points with impedance in the range of 0 Ω ~ 38Z0(Z0 is the characteristic impedance of the cable), and the fault location error is less than 0.4%. Compared with ICE method and TDR method, this method is more sensitive, which can be adopted to realize the type identification and high-precision positioning of cable faults.