Cable initial-stage arc fault modeling method

Abstract

The invention discloses a cable initial-stage arc fault modeling method. Initial-stage arc faults are main manifestation forms of early degradation of cable insulation. The method comprises the following steps: for a widely used cross-linked polyethylene (XLPE) cable, measuring a typical characteristic curve of initial-stage arc fault voltage of a cable through a high-voltage experiment; analyzing and counting four key characteristic quantities including an arc starting time point, arc duration time, arc combustion duration voltage and insulation recovery overvoltage of the initial-stage arc fault, and fitting voltage characteristics of the initial-stage arc fault by adopting a CSC function; and finally, based on the fitted initial-stage arc fault voltage function, constructing a cable initial-stage arc fault model of the time-varying voltage-controlled nonlinear resistor, and giving model parameters. According to the method, the blank in the aspect of cable initial-stage arc fault modeling is filled, a model basis is provided for early warning, analysis and positioning of subsequent cable initial faults, and the method has important practical value.

Description

technical field [0001] The invention belongs to the technical field of power cables, and in particular relates to a modeling method for arc faults of XLPE cables. Background technique [0002] The cable arc fault originates from the partial insulation defect of the cable, and generally occurs between the cable core conductor and the metal shielding layer, such as figure 1 shown. The initial arc specifically refers to the arc whose duration is less than 1 / 4 of the power frequency cycle. It is the most common early fault form of the cable, and its occurrence indicates the beginning of the cable insulation breakdown. Unlike multi-cycle arcs that approach permanent faults, incipient arcs undergo repeated reignitions and arc extinctions, which may last for days or even months. Therefore, the initial arc fault has always been the most valuable research focus of cable fault prediction. [0003] The initial arc fault model is the key to arc fault analysis. However, due to the va...

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Problems solved by technology

This difference can have a significant impact on arc fault detection and localization algorithms

[0004] At present, due to the lack of suitable on-site measurement methods and the interference of the transmission network, it is difficult to capture effective cable initial arc fault waveforms for modeling in practice. Therefore, arc modeling based on experimental measurements has become the only means for arc fault related technology research.

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