Cable joint cable core temperature inversion method and system based on cable surface temperature

Abstract

The invention provides a cable joint core temperature inversion method and system based on the cable surface temperature, comprising: step 1, performing radial temperature inversion according to the one-dimensional transient thermal circuit model of the cable and the surface temperature measurement point temperature of the cable body Step 2: Use the finite element temperature field simulation method to construct a two-dimensional cable temperature field simulation model, and simulate the cable core contact point and cable core at different loading currents and different times The transient temperature of the fitting point is obtained to obtain the transient temperature simulation data set; step 3, taking the transient temperature of the cable core contact point as the independent variable and the transient temperature of the cable core fitting point as the dependent variable, the transient temperature simulation data set Perform fitting to obtain the cable core axial temperature function; step 4, combine the cable core fitting point inversion transient temperature and the cable core axial temperature function to obtain the cable core contact point temperature. The present invention utilizes the surface temperature of the cable body to obtain accurate cable core contact point temperature through inversion and fitting, which is simple and convenient.

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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