Method and device for evaluating influence of environment thermal resistance on three-core cable core temperature

Abstract

The invention relates to a method and device for evaluating the influence of environment thermal resistance on the three-core cable core temperature. The method includes the steps that the environment thermal resistance under air laying and / or the environment thermal resistance under soil laying are / is obtained according to a thermal circuit model of a three-core cable; the cable core temperature of the three-core cable is obtained according to the thermal circuit model of the three-core cable; if the three-core cable is under air laying, the sensitivity to the environment thermal resistance under air laying by the cable core temperature is determined according to the relation between the environment thermal resistance under air laying and the environment temperature and a formula (please see the specification for the formula); if the three-core cable is under soil laying, the sensitivity to the environment thermal resistance under soil laying by the cable core temperature is determined according to a formula (please see the specification for the formula). By the adoption of the method and device, the influence degree to the three-core cable core temperature by the environment thermal resistance can be accurately analyzed; in accordance with the magnitude of the sensitivity in the air laying process or the soil laying process, when the loading current of the three-core cable is large and the laying of the three-core cable is air radiation particularly, environment temperature monitoring is enhanced, and therefore the safe and stable operation of an electrical power cable is guaranteed.

Description

technical field [0001] The invention relates to the technical field of power cables, in particular to an evaluation method for the influence of environmental thermal resistance on the core temperature of a three-core cable and an evaluation device for the influence of environmental thermal resistance on the core temperature of a three-core cable. Background technique [0002] The temperature of the wire core during the operation of the power cable is the basis for determining whether the power cable has reached the current carrying capacity. The cable ampacity is an important dynamic operating parameter affected by environmental conditions and load factors during cable operation, and its importance affects the safety and reliability of transmission lines, economical and reasonable operation, and cable life. If the ampacity of the cable is too large, the working temperature of the cable core temperature will exceed the allowable value, which will affect the life of the insula...

AI Technical Summary

Problems solved by technology

However, since the current-carrying capacity of the cable line in actual operation is affected by many factors, such as the external environment (ambient temperature and environmental thermal resistance, etc.), the IEC60287 series standards ignore many external factors in the calculation of the current-carrying capacity, so it cannot be accurately calculated. Ampacity

In addition, the research on applying the sensitivity analysis of the core temperature to the external environment to the single-core cable at home and abroad has become mature. Far more complex than single-core cables, so the sensitivity analysis of existing single-core cables cannot be applied to three-core cables

Images