Digital simulation of fault location on EHV lines using wideband spread spectrum techniques

Spread spectrum techniques perform well in high-noise environments such as power lines, and their use in radar ranging is well known. Existing power line carrier (PLC) equipment may be used to transmit a direct sequence signal down a faulted EHV line. The fault position may then be calculated from correlation analysis of the reflected waveforms. This fault-location process has been simulated on a digital computer by taking into account the frequency variation of the PLC interface and line parameters over the spread spectrum bandwidth. The effect of waveform characteristics and fault location are examined for a 100 km double transposed line with a single phase to ground fault. Results indicate that permanent faults may be located to within 0.5 km