Concepts and Methods to Assess the Dynamic Thermal Rating of Underground Power Cables

Abstract

With the increase in the electrical load and the progressive introduction of power generation from intermittent renewable energy sources, the power line operating conditions are approaching the thermal limits. The definition of thermal limits variable in time has been addressed under the concept of dynamic thermal rating (DTR), with which it is possible to provide a more detailed assessment of the line rating and exploit the electrical system more flexibly. Most of the literature on DTR has addressed overhead lines exposed to different weather conditions. The interest in the dynamic thermal rating of power cables is increasing, considering the evolution of computational methods and advanced systems for cable monitoring. This paper contains an overview of the concepts and methods referring to dynamic cable rating (DCR). Starting from the analytical formulations developed many years ago for determining the power cable rating in steady-state conditions, also reported in International Standards, this paper considers the improvements of these formulations proposed during the years. These improvements are leading to include more specific details in the models used for DCR analysis and the computational methods used to assess the power cable’s thermal conditions buried in soil. This paper is focused on highlighting the path from the initial theories and models to the latest literature contributions. Attention is paid to thermal modelling with different levels of detail, applications of 2D and 3D solvers and simplified models, and their validation based on experimental measurements. A salient point of the overview is considering the DCR impact on reliability aspects, risk estimation, real-time calculations, forecasting, and planning with different time horizons.

The Effect of the Vertical Layout on Underground Cable Current Carrying Capacity

“…Since the diameter of the 150 mm 2 aluminum cable is 4 cm, the channel height is calculated as 50 cm according to Equation (12). The channel width is calculated as 30 cm according to Equation ( 14).…”

“…Thermal monitoring is a popular subject in the literature related to cable studies. By constantly monitoring the temperatures of cables online, studies could calculate the remaining life of the cables, perform dynamic calculations of ampacity values, plan dynamic line loading, and analyze critical loading conditions [12].…”

Editorial for the Special Issue “Verifying the Targets—Selected Papers from the 55th International Universities Power Engineering Conference (UPEC 2020)”

“…Underground cables, widely used in distribution systems, can benefit from a "dynamic rating", in particular, for the lines that are subject to an increase of demand and carry current from intermittent renewable generation. Enescu et al [6] provide an overview of the concepts and the methods related to the dynamic cable rating, with a focus on models, solution methods, reliability and monitoring issues and the impact on distribution systems operation with different time horizons.…”

Thermal-mechanical coupling simulation analysis of submarine armored cable soil environment

“…Under extremely complex conditions, submarine cables are vulnerable to external factors. Once the submarine cable fails and stops operation, it will cause great economic losses [1][2][3]. Statistical data show that 95 % of the cable damage is caused by human activities such as fishing and shipping, mainly due to external damage caused by fishing gear and ship anchor.…”