Cable current-carrying capacity calculation method and device when water is accumulated in a power pipe

Abstract

The invention provides a cable current-carrying capacity calculation method and device when water is accumulated in a power pipe. The method comprises the following steps: obtaining parameters according to the model of a cable and the model of a cable pipeline; obtaining the height h of accumulated water in the cable pipeline, and calculating the thermal resistance T41water of the accumulated water in the pipe and the thermal resistance T41air of an air layer in the pipeline based on the height h, the outer diameter De, the inner diameter Dd and the thermal resistance T41 of the air layer in the pipeline; judging whether the height h is greater than the outer diameter De; according to a judgment result, calculating by using different calculation methods to obtain a ratio mu1 of the heat dissipating capacity of the outer skin to the water relative to the total loss of the cable, a ratio mu2 of the heat dissipating capacity in the air relative to the total loss of the cable, and a contact area Sw of accumulated water and the air in the pipe per unit length; calculating heat Wwa emitted by accumulated water in the pipe to the air layer in the pipeline based on the Sw; and calculating the current-carrying capacity I of the cable when water is accumulated in the pipe by using the heat Wwa and the parameters.

Description

technical field [0001] The invention belongs to the technical field of electric digital data processing, and in particular relates to a method and device for calculating the ampacity of a cable when there is water accumulation in an electric power pipe. Background technique [0002] In most of the southern regions of our country, due to the rainy weather and the shallow groundwater level, it is inevitable that the power pipes will seep into the groundwater, and even the cables in some urban pipe projects have been soaked in stagnant water for a long time, even after the implementation of mechanical drainage. There is still a small amount of accumulated water in the pipe. Through the investigation of power pipes in a certain area of ​​Jiangsu, it is found that most of the power pipes in the city have accumulated water, and most of the running 10kV cables are soaked in accumulated water, and the existence of accumulated water has an impact on the carrying capacity of power cab...

AI Technical Summary

Problems solved by technology

Through the investigation of power pipes in a certain area of ​​Jiangsu, it is found that most of the power pipes in the city have accumulated water, and most of the running 10kV cables are soaked in accumulated water, and the existence of accumulated water has an impact on the carrying capacity of power cables It is very large. When there is water accumulation in the power pipe in the actual project, the existing calculation scheme of cable ampacity has defects, and it is impossible to obtain more accurate calculation results.

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