Research on surge arc prolongation device for power cable fault location

The development of an arc prolongation device for the secondary impulse method used in power cable fault location is reported in this paper. The faulty cable breaks down by a HV surge. Prior to the arc extinguishing, the device will supply, automatically, the energy to the faulty cable to sustain the arc sufficiently for the secondary impulse test. The device consists of an energy generator, wave blocker, impulse duration modulator, and signal coupler which are mounted in a compact case. This makes it easy to link the device with the surge generator and faulty cable on site. Since the output voltage is low, the device is safe for the cable's good insulation. Both simulations and laboratory tests show the device can prolong the arc for many milliseconds. The on-site secondary impulse method tests using this device produces fault location waveforms on the instrument's screen.