Application of distributed traveling wave ranging technology in fault diagnosis of HVDC transmission line

Traveling wave ranging technology has been widely used in DC transmission line fault diagnosis. However, since the transmission distance of HVDC transmission lines is very far, the influence of line parameters and traveling wave attenuation effect on the ranging accuracy is more obvious, which makes the positioning accuracy of the DC-line traveling wave ranging technology insufficient, and the cause of failure cannot be identified. In addition, in case of some non-lightning failures, it is difficult for traveling wave monitoring equipment in the substation to detect the fault traveling wave, resulting in failure to locate fault points. This article describes a new type of traveling wave location technology, which is called distributed traveling wave ranging technology. The technology uses distributed monitoring terminals installed on the conductors of HVDC transmission lines to collect operating current and traveling wave current waveforms on the conductors, and accurately locates the fault points through single-end and double-end traveling wave positioning technology, reducing the influence of line span and traveling wave attenuation effect on the fault location accuracy. Finally, a lightning flash fault and a mountain fire fault diagnosis case for a +/- 500 kV DC transmission line are analyzed. The analysis results show that the distributed traveling wave ranging technology can reliably diagnose the fault of the HVDC transmission line.