Evaluation method of 10kV three-core cable conductor temperature

Abstract

The invention discloses an evaluation method of 10kV three-core cable conductor temperature, wherein the conductor temperature is calculated based on the measured cable skin temperature, and the influence of the complicated change of the external environment temperature and environment thermal resistance on the 10kV three-core cable under different laying conditions and different operation environment conditions is avoided, thus the evaluation result is more accurate, and the application range is wider. Moreover, the evaluation method also performs equivalent and simplification treatment in calculation: neglecting the thermal resistance of a conductor shielding layer, considering the conductor and the conductor shielding layer as one layer, and deeming that the temperature of the conductor shielding layer is equal to the temperature on the outer surface of the conductor; considering the insulation shielding in an insulating layer and deeming that the thermal resistance coefficients of the two are equal; and neglecting the loss and thermal resistance of the 10kV three-core cable metal shielding layer. Thus, the method simplifies the operation while guaranteeing the calculation accuracy.

Description

Technical field [0001] The invention relates to the technical field of transmission cables, in particular to a method for evaluating the conductor temperature of a 10kV three-core cable. Background technique [0002] At present, in order to obtain the temperature of the 10kV three-core cable conductor and determine the current carrying capacity, there are usually two methods: the equivalent thermal circuit model calculation method represented by the IEC standard; and the simulation numerical calculation method represented by the finite element simulation. [0003] The calculation method of the heat circuit model represented by the IEC standard: According to the principle of heat transfer, the cable body and its surrounding environment are constructed as a one-way heat transfer heat circuit with heat source and thermal resistance. The heat source and thermal resistance parameters are determined according to the conductor It depends on the heat generation, dielectric loss of the insu...

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Problems solved by technology

[0004] The above method has the following defects: 1. The surface of the earth is an isothermal surface; 2. The surface of the cable is an isothermal surface; 3. The principle of superposition is applicable; 4. The specified calculation conditions are very harsh

[0006] Defects: 1. Different models need to be established for different situations, and the universality is insufficient; 2. Structural parameters, thermophysical parameters and boundary conditions must be set accurately, otherwise it will lead to large errors

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