Method for determining through-flow upper limit of high-voltage direct-current plastic insulation cable accessory

Abstract

The invention discloses a method for determining through-flow upper limit of high-voltage direct-current plastic insulation cable accessory. The method comprises following steps: building a finite element model; calculating the highest temperature of a wire core under different load currents and the maximal temperature difference allowed by the exterior surface inside each solid insulation layer; taking the highest long-term allowable temperature of the wire core and the maximum allowable temperature difference between inside and outside surfaces of each solid insulation layer as restricting conditions for the steady load flow of high voltage direct current cable attachment to get an initial current loading section; using the ideas of dichotomy to continuously narrow the current loading section and finally obtaining the steady load flow of high voltage direct current cable attachment. During the operation of high voltage direct current cable attachment, taking the calculated result of load carrying capacity as the through-flow upper limit of the attachment. In the invention, both the highest long-term allowable temperature of the wire core and the maximum allowable temperature difference between inside and outside surfaces of each solid insulation layer are taken as two restricting conditions, which meets the insulation characteristics of high voltage direct current cable attachment. With the method, it is possible to flexibly adjust the load carrying capacity of the attachment in accordance to exterior environment. The method makes full use of the transmission capacity of an electric cable line, therefore, increasing the utilization efficiency of an electric cable.

Description

technical field [0001] The invention relates to the field of electric power technology, in particular to a method for determining the upper limit of the current flow of high-voltage DC plastic insulated cable accessories (including terminals and joints). Background technique [0002] Accurate calculation of the steady-state current carrying capacity of HVDC cable accessories and the determination of the upper limit of the current flow are of great significance for the full utilization of its transmission capacity. [0003] At present, the method of determining the current carrying capacity of the cable body is mainly based on the analytical calculation method based on IEC60287 and the numerical calculation method using boundary elements, finite difference, and finite elements. It can be seen that the research on the current-carrying capacity of the cable body has been perfected day by day, but there is still a lack of in-depth research on the relationship between the tempera...

AI Technical Summary

Problems solved by technology

It can be seen that the research on the current carrying capacity of the cable body has been gradually improved in the current stage, but there is still a lack of in-depth research on the relationship between the temperature distribution and the current carrying capacity of the cable accessories.

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