Steady-state iteration measuring method for current-carrying capacity of cable

Abstract

The invention discloses a steady-state iteration measuring method for the current-carrying capacity of a cable. The method includes the first step of measuring the skin temperature of the cable and the environment temperature of the cable, and the second step of obtaining initial cable environment thermal resistance according to the skin temperature of the cable and the environment temperature of the cable and calculating the current-carrying capacity of the cable in an iteration method. According to the steady-state iteration measuring method for the current-carrying capacity of the cable, the skin temperature of the cable and the environment temperature of the cable are measured, the current-carrying capacity of the cable is calculated according to the measured skin temperature of the cable and the measured environment temperature of the cable in the iteration method, and calculation of the thermal resistance is referred to when the current-carrying capacity of the cable is calculated; the thermal resistance includes cable internal thermal resistance and environment thermal resistance, and the environment thermal resistance changes along with the change of the cable load; the change of the environment thermal resistance is taken into account in the iteration method so that a calculation error of the current-carrying capacity of the cable can be smaller.

Description

technical field [0001] The invention relates to a method for measuring the ampacity of a cable, in particular to a steady-state iterative method for measuring the ampacity of a cable, and belongs to the technical field of electric power. Background technique [0002] The cable ampacity is an important parameter in the cable line. The accurate calculation of the cable ampacity has an important guiding role for the cable design department and the cable operation department, and is of great significance to the safe operation of the entire power system. [0003] At present, the method of determining the ampacity is generally calculated according to the IEC60287 and IEC60853 standards. The ampacity obtained through the IEC standard has a large margin compared with the actual ampacity of the cable, and the error is large. Taking the IEC60287 standard as an example, this standard simplifies the environment into a single uniform heat transfer medium. In fact, the cable heats up duri...

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Problems solved by technology

The ampacity obtained through the IEC standard has a large margin compared with the actual ampacity of the cable, and the error is large. Taking the IEC60287 standard as an example, this standard simplifies the environment into a single uniform heat transfer medium. In fact, the cable heats up during operation. Changes in the surrounding environment lead to large errors in calculation results and inaccurate current carrying capacity

[0004] The calculation of cable ampacity involves the calculation of thermal resistance, including the internal thermal resistance of the cable and the thermal resistance of the environment. The thermal resistance of the environment changes with the change of the cable load. The current calculation method regards the thermal resistance of the environment as a constant, which makes the calculation error There is a certain error

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