Novel online fault diagnosis method for high-voltage XLPE cable

Abstract

The invention discloses a novel online fault diagnosis method for a 110kV XLPE cross interconnection cable, namely a trajectory method. According to the method disclosed by the invention, cable metal sheath grounding wire loop current and operating voltage parameters are acquired through an online monitoring system, the parameters are transmitted to a computer, and a trajectory diagram integrating the two types of parameters in the same time period is constructed. Any fault corresponds to a different trajectory diagram, and differences between the trajectory diagram and normal conditions are analyzed and compared by using digital image processing technologies so as to carry out fault diagnosis accurately. The fault diagnosis method disclosed by the invention can overcome deficiencies of a traditional online monitoring and fault diagnosis method, is higher in accuracy and lower in cost, can realize real-time diagnosis, and can form a historical fault trajectory database.

Description

technical field [0001] The invention relates to a new online fault diagnosis method for 110kVXLPE cables, which belongs to the technical field of electric power. Background technique [0002] Cross-linked polyethylene (XLPE) cables have the advantages of light structure, excellent electrical performance, and convenient laying, and have been widely used in high-voltage power grids. During the operation of the power cable, it will be affected by the complex external environment, such as multiple factors such as electricity, magnetism, heat, chemistry, and machinery. There may also be local defects such as insulating air gaps and protrusions during the manufacturing process, which will promote the gradual deterioration of the cable insulation. Aging will eventually cause partial discharge, leading to the breakdown of the main insulation of the cable and a ground fault. The insulation of the outer sheath of the cable may have the following faults: First, the damage of the sheat...

AI Technical Summary

Problems solved by technology

[0005] At present, online monitoring methods such as DC component method, dielectric loss factor method, partial discharge method, and grounding wire current method have been proposed at home and abroad. Although these methods are theoretically feasible for high-voltage XLPE, they all have shortcomings. The monitoring signal is too small to obtain, the installation of the monitoring device is complicated and the cost is high, so there are still many difficulties in implementing these methods in the field

At the same time, the currently recognized cable fault location and diagnosis methods include impedance method and traveling wave method, but due to the limitation of the scope of use and accuracy, the expected results have not been achieved.

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