High-voltage cable protector fault on-line detection method based on sheath current angle difference

Abstract

The invention relates to a high-voltage line fault detection technology, in particular to a high-voltage cable protector fault on-line detection method based on a sheath current angle difference, which comprises the following steps: establishing a three-phase nine-section crossed and interconnected high-voltage cable equivalent model; current sensors installed at the head end and the tail end of the crossed interconnection cable line are used for measuring sheath current; establishing a transfer function of fault impedance and sheath current difference of the sheath protector; and performing fault diagnosis on the sheath protector by taking the current difference phase angle as a characteristic quantity. And in the process of formulating the diagnosis criterion, the influence of the size of the cable core current, the working voltage fluctuation, the ground impedance, the length of a small section of cable and the fault degree of the sheath protector on the sheath current is considered. According to the detection method, the maintenance efficiency and the fault diagnosis accuracy of the sheath protector at the present stage are improved.

Description

technical field [0001] The invention belongs to the technical field of high-voltage line fault detection, and particularly relates to an on-line fault detection method for a high-voltage cable protector based on a current angle difference of a sheath. Background technique [0002] At present, the existing cable fault detection methods are mainly aimed at faults such as epoxy board breakdown, grounding box water ingress, and sheath damage. The fault of the sheath protector still relies on manual inspection. In addition, most of the current detection methods use sheath current amplitude, sheath current relative value and sheath current to load current ratio for fault diagnosis of cable grounding system. In some cases, these diagnostic criteria cannot be used as sheath protectors. The only basis for fault diagnosis is to use the sheath current phase angle to improve the accuracy of fault diagnosis. SUMMARY OF THE INVENTION [0003] In view of the problems existing in the bac...

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Problems solved by technology

[0002] At present, the existing cable fault detection methods are mainly aimed at faults such as epoxy board breakdown, water ingress in the grounding box, and damage to the sheath. The fault of the sheath protector still relies on manual inspection.

Moreover, most of the current detection methods use the sheath current amplitude, the relative value of the sheath current and the ratio of the sheath current to the load current to diagnose the fault of the cable grounding system. In some cases, these diagnostic criteria cannot be used as the The only basis for fault diagnosis, it is also necessary to use the sheath current phase angle to improve the accuracy of fault diagnosis

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