Projects:2021s1-13005 Determining Dynamic Line Ratings of Over-Head Transmission Conductors based on Line Tension
Project Team Members
- Andrew Gross
- Michael Iuliano
- Taimur Abdullah Said Al-Sanaidi
Staff
Principal Supervisor: Wen Soong
Co-Supervisor: David Vowles
ElectraNet Sponsors:
Abstract
This project sponsored by ElectraNet aims to develop a tension-based model to dynamically alter line ratings on transmission lines. This will allow for existing infrastructure to have a longer lifespan.
Introduction
The 2021 iteration of this project continues on from the work completed in the project of the same name[1] 2020 by Adrian Barone and James Smithson.
Thermal Factors
There are four main factors when considering the various thermal effects on an overhead conductor. These are:
- Current Heating(Joule Heating) - Due to resistive and magnetic losses of the conductor material while it is conducting current. The resistive losses are due to both the conducting material and the increase in the resistance of the conductive material as its temperature increases.
- Solar Heating - This is heating due to direct radiation from the sun. Typically, direct solar radiation is difficult to calculate as direct and diffuse solar radiation has various challenges in measuring it (expensive for sensors, need regular attention). In some cases where this data isn’t available, global solar radiation is used.
- Convective Cooling - Convective Cooling occurs per the effect of the air surrounding the conductor heating, reducing the density of the air around the conductor causing cooler air replaces it.
- Radiative Cooling - This is the effect of the material emitting thermal radiation, losing heat in the process. A simplified equation is used as the radiation loss is a small fraction of the total cooling.
We do not consider Corona Heating as it is unlikely to occur under typical operation of the conductor, nor Evaporative Cooling as while it has a significant effect on cooling, it is challenging to assess along the whole conductor and separated from wind effects, so is ignored.
