Method and system for obtaining thermal resistance of three-core cable packing layer

Abstract

The invention discloses a method and system for obtaining the thermal resistance of a three-core cable packing layer. The method comprises the following steps that the inner radius of an inner sheath layer of a three-core cable and the inner radius of metal shielding layers are obtained; a shape factor of the three-core cable packing layer is obtained according to the inner radius of the inner sheath layer and the inner radius of the metal shielding layers; the thermal conductivity coefficient of materials of the three-core cable packing layer is obtained, and the thermal resistance of the three-core cable packing layer is obtained according to the shape factor and the thermal conductivity coefficient. The method for calculating the thermal resistance of the three-core cable packing layer though the shape factor is provided, and the thermal resistance of the packing layer can be obtained simply by measuring certain structural parameters of the three-core cable. By means of the method and the system, parameters of a thermal path model can be effectively corrected, and great significance for accurately calculating the cable conductor temperature and achieving the real-time monitoring on distribution network cables is achieved.

Description

【Technical field】 [0001] The invention relates to the field of distribution network technology, in particular to a method and system for obtaining the thermal resistance of a filling layer of a three-core cable. 【Background technique】 [0002] At present, the methods for calculating the conductor temperature of three-core cables in distribution networks at home and abroad can be divided into two categories: analytical algorithms and numerical algorithms. The analytical algorithm is mainly the thermal path method. The thermal path method is to establish a thermal path model based on the heat transfer characteristics from the conductor to the cable surface inside the cable. The thermal circuit model consists of components such as thermal resistance, thermal capacity, and heat source that represent the material properties of each layer of the cable. Among them, thermal resistance is used to represent the hindering effect of each layer of material on the cable heat dissipation...

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Problems solved by technology

For the calculation of thermal resistance, there are relevant calculation formulas in the IEC standard, but the IEC standard mainly uses empirical data to perform equivalent calculations on the thermal resistance of the materials of each layer of the three-core cable, and does not include the transient thermal circuit of the three-core cable. Model research, lack of theoretical basis, large error

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