Electricity Grid Overhead Cable Insulator Acoustic Noise

In recent years, significant works have been carried out in Scotland and elsewhere in the UK to replace and upgrade older parts of the electricity distribution grid. However, in several cases local residents have complained about an audible noise coming from the new power lines. A very short preliminary computer modelling exercise was carried out by researchers in the Centre for Ultrasonic Engineering at the University of Strathclyde in collaboration with overhead line engineers at Scottish and Southern Electricity Networks (SSE). This led to the conclusion that the shape of the glass (or ceramic/porcelain) disc insulators used in high voltage overhead cables interacting with the wind causes these insulators to create an audible noise.

Looking forward, the UK plans to reach net zero carbon emissions by 2050. To do this the country will need to intensify the electrification of power use, for example through the switch to electric cars, and electricity for domestic household heating and cooking replacing gas. At the same time, electricity generation will shift to renewable sources, as fossil fuel generator use is reduced. In 2020 fossil fuels made up 84% of the global energy mix, but this figure will need to fall to less than 20% by 2050 in order to reach net zero. At the same time, it’s estimated that electricity consumption in the UK will increase approximately 50% by 2036 and more than double by 2050. This will consequently require larger and more powerful grid systems. As a vital component in electrical distribution systems, the global high voltage glass insulator market size was projected to be worth $11 billion in 2023, and is likely to surpass $15.5 billion by 2033. Increased electrification in the UK will necessitate not only larger insulator implementations, but also lead to more large-scale installations closer to residential housing and other buildings, with potential for significant acoustic noise aggravation to local residents from wind driven noise on the high voltage cable insulators.

This PhD aims to investigate the acoustic wind-driven noise created by the designs of disc insulators currently in use in Scotland and the wider UK. Following on from work in the preliminary study, analytical models, and 2D and 3D computer modelling and simulation of the structure, structural resonances, wind flow, and acoustic resonances will be made in order to confirm the mechanism of sound production. This will be followed by simulations to test the influence of factors such as wind speed and direction on the sounds generated across the different disc designs. The PhD will then investigate ways to mitigate the acoustic noise problem, considering the environment and location of cable insulators, the overall implementation of insulators at a site, and finally exploring how insulator discs could be redesigned to reduce acoustic noise (while retaining sufficient insulation function).

The PhD student will work in collaboration with SSE overhead line engineers to investigate how this ever more significant noise problem can be best mitigated as Scotland and the UK renews and increases the capacity of its electricity grid for future electrification. SSE will provide the student with an array of examples of different overhead cable disc insulators, as well as design and material data. The student will also have access through SSE to site data from known instances of acoustic noise, and will have the opportunity to visit sites to undertake acoustic measurements, as well as the opportunity to spend 3 months on placement at SSE in Glasgow.