Cable-joint cable core temperature inversion method and system on basis of surface temperature of cable

Abstract

The invention provides a cable-joint cable core temperature inversion method and a cable-joint cable core temperature inversion system on the basis of a surface temperature of a cable. The cable-joint cable core temperature inversion method comprises the following steps: S1, carrying out radial temperature inversion according to a cable one-dimensional transient thermal circuit model and a temperature of a surface temperature measured point of a cable body so as to obtain an inversion transient temperature of a cable core fit point; S2, constructing a cable two-dimensional temperature field simulation module by adopting a finite element temperature field simulation method and simulating transient temperatures of a cable core contact point and the cable core fit point under different loading currents and at different moments so as to obtain a transient temperature simulated data set; S3, using the transient temperature of the cable core contact point as an independent variable, using the transient temperature of the cable core fit point as a dependent variable and carrying out fitting on the transient temperature simulated data set so as to obtain a cable core axial temperature function; S4, combining the inversion transient temperature of the cable core fit point with the cable core axial temperature function to obtain a temperature of the cable core contact point. According to the invention, the accurate temperature of the cable core contact point can be obtained by utilizing the surface temperature of the cable body through inversion and fitting; the cable-joint cable core temperature inversion method and the cable-joint cable core temperature inversion system are simple, convenient and rapid.

Description

technical field [0001] The invention belongs to the technical field of on-line monitoring for disaster prevention and mitigation of power cables, and in particular relates to a cable joint cable core temperature inversion method and system based on the surface temperature of the cable. Background technique [0002] Power cable is an indispensable and important part of the power system and undertakes the heavy responsibility of power transmission. Due to the aging of the cable joint insulation, the partial discharge current in some areas becomes larger, especially in the case of high load, which causes a sharp temperature rise inside the cable joint, and the resulting explosion of the joint poses a threat to the safe and stable operation of the transmission line. The on-line monitoring technology for disaster prevention and mitigation of power cables needs to be improved urgently. At present, the commonly used on-line monitoring technologies for power cables at home and abro...

AI Technical Summary

Problems solved by technology

Due to the characteristics of the cable itself, the accessories (terminals, joints) need to be installed on site after the laying is completed. The production is affected by the adverse factors of the site environment and the limitation of the production process, and the crimping quality of the cable intermediate joint can only be tested during operation.

The longer its running time, the more prone to overheating and burn-through accidents

At the same time, after a period of high current (overload) operation, overheating and oxidation often occur at the crimping point, which gradually increases the contact resistance and the temperature of the contact point, aging the insulation, and eventually causing damage to the insulation layer and causing accidents. occur

However, the existing above-mentioned technologies are mainly an indirect monitoring of the cable aging state, and cannot directly provide timely early warning of power cable faults, which may easily cause cable accidents.

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