World-first research aiming to reduce overhead line noise impacts

A blog by Isobel Green

Isobel Green is a Graduate Trainee who joined SSEN Transmission two years ago as part of our Graduate Programme. She was recently shortlisted for the Energy Champion of the Year award in the Energy Awards 2024, for her industry-leading research to mitigate weather-related overhead line noise. In this article she shares what motivated her to embark on her work, and how she hopes it will have a global impact. 

Last year, I began researching methods to mitigate noise from overhead lines, caused by the poor and occasionally strange weather that we typically encounter in Scotland!   
 
Through this we came across a puzzling issue, where an overhead line was causing a disturbance even though rainfall in the area was relatively low. Within our industry, it was understood that lower rain rates would result in lower conductor noise, but here we had what appeared to be the opposite effect.  
 
Noise impact is an issue that we are continually seeking to understand and improve our approach towards as we aim to limit disturbance to communities, so to address this issue we undertook a preliminary investigation which concluded that the atmospheric conditions in the area (where there was a lot of mist, fog, and drizzle) was the likely cause.

Our main challenge in proving our theory was the lack of prior research on the relationship between very low rain rates such as mist, fog and drizzle, and the noise level produced by an overhead line – particularly as there was previously no technology available to quantify these low rain rates. 
 
To overcome the gaps in our knowledge, we set to work creating a completely new test setup in the lab to replicate the field conditions we were measuring with an instrument called a disdrometer.  

It took several iterations and extensive field measurement data to refine the setup for testing at very low rain rates, but through this process we were able to show that at very low rates, water droplets can collect on the conductor's surface, saturating it and resulting in high noise levels.  
 
Having established this relationship, we’re now working to apply our learning to our own projects while sharing what we’ve learned with the wider industry. Our next steps involve collaborating with other Transmission Network Operators (TNOs) across the UK and globally to determine how best to apply our findings to current practices. This could mean updating the estimation process or informing the impact assessment of overhead line noise.  
 
Reflecting on the work I’ve done over the past two years, I am proud to have made a contribution that I’m confident can help reduce potential noise impacts caused by overhead lines, both in the north of Scotland and potentially elsewhere across the world.  

At the start of this journey, I never expected to be completing world-first research or co-authoring a paper based on it, so it was incredibly exciting to be shortlisted for Energy Champion of the Year, even though the award went to someone else. I always aim high in everything I do, but I never thought I’d receive this level of recognition – it’s an incredible reminder that what my team and I are doing is making a difference in our company and the wider industry.