Fault Diagnosis and Location for Long Submarine Cable Based on Frequency Domain Refection

Abstract

Time Domain Refection is widely used for the fault location on submarine cable. While, for high resistance and intermittent faults, Time Domain Refection is far from enough. It gives a brief description about the fault diagnosis on submarine cable based on Frequency Domain Refection. A high-frequency signal with a frequency step size is sent to the cable, then it will give a reflected signal from the point of impedance mismatch, in which the information about the cable impedance changing could be get to locate the fault. It just need to send a low voltage signal, without burning down to give a physically damaging by the high voltage generator or pulse generator. It could be used for the location of low resistance faults, high resistance faults, as well as intermittent faults. Test has been done in Hainan Interconnection Project, which has the first ultra-high voltage and the longest submarine cable with the highest capacity in China. In the site test, not only the location of short-circuit fault and open-circuit fault in the other end of cable. What's more, we could also find the factory joint, turn point of the route, and the exposing and suspending point where the protection of the cable was damaged. The application of fault location based on Frequency Domain Refection has a significant result.