Research on the rapid calculation method of temperature rise of cable core of duct cable under emergency load

Abstract

In order to facilitate engineers to manage dynamic loads in real time and improve the utilization of power cables, it is necessary to accurately calculate the temperature rise of cable cores under duct laying conditions. The transient thermal circuit model involved in this paper helps to improve the speed of dynamic response and the accuracy of transient temperature rise calculation for power cable cores under duct laying conditions. Since the impact of the environmental conditions, exploring the computational relationships of the thermal circuit model parameters helps to improve the engineering applicability of the model. The duct cable can be broken down into three parts: the cable body, the air inside the pipe and the external environment. In engineering, the thermal circuit model parameters of the cable body can be made into a table and applied by looking up the table. The thermal circuit model parameters of air in duct are related to the cable outside diameter and duct inside diameter, and can also be engineered using tables for application. The fit gives the third part of the equation with respect to the thermal resistance coefficient of the duct and soil and the burial depth. The error in applying the decentralized thermal circuit model and parametric expressions is less than 1 °C compared to the results of finite element calculations. This proves that the decomposition of the duct power cable model improves the accuracy of the transient temperature rise calculation. The relationship equation between the parameters of the thermal circuit model and the laying conditions helps to improve the engineering adaptability of the method.

Keywords

• Power cable in ducts
• Transient temperature rise
• Emergency load
• Transient thermal circuit model